diff --git a/engines/claude.json b/engines/claude.json
index 9aec23a4c..f5b1c013a 100644
--- a/engines/claude.json
+++ b/engines/claude.json
@@ -53,6 +53,8 @@
   "companion": {
     "protocol": "stream-json",
     "serverCmd": ["--print", "--verbose", "--input-format", "stream-json", "--output-format", "stream-json", "--max-turns", "1"],
+    "systemPromptFlag": "--system-prompt",
+    "textOnlyArgs": ["--tools", ""],
     "features": {
       "threadResume": false,
       "nativeReview": false,
diff --git a/packages/adapter-cli/src/generated/adapter-helpers.ts b/packages/adapter-cli/src/generated/adapter-helpers.ts
index 07c4c0be0..503d4718d 100644
--- a/packages/adapter-cli/src/generated/adapter-helpers.ts
+++ b/packages/adapter-cli/src/generated/adapter-helpers.ts
@@ -1,6 +1,6 @@
 // @generated by kern v4.5.0 — DO NOT EDIT. Source: src/kern/adapter-helpers.kern
 
-// @kern-source: adapter-helpers:520
+// @kern-source: adapter-helpers:525
 
 import type { EngineDefinition, EngineMode, EngineModeConfig, ImageAttachment, EngineIsolationPlan } from '@kernlang/agon-core';
 
@@ -324,12 +324,13 @@ export function resolveAgentArgs(engine: EngineDefinition, permissionLevel: 'ful
 }
 
 /**
- * Extract text content from Claude stream-json NDJSON output. Returns plain text with system/hook messages removed.
+ * Extract text content from Claude stream-json NDJSON output. The final result event is the authoritative answer when present — concatenating it with the assistant text blocks duplicates the answer, and in multi-turn tool runs the early assistant texts are tool preambles ('I'll quickly verify...'), not the answer. Assistant texts remain the fallback for streams the result never closed (timeout kill, max-tokens is_error).
  */
 // @kern-source: adapter-helpers:297
 export function stripStreamJson(stdout: string): string {
   const lines = stdout.split('\n');
-  const textParts: string[] = [];
+  const assistantParts: string[] = [];
+  let resultText = '';
 
   for (const line of lines) {
     const trimmed = line.trim();
@@ -339,27 +340,31 @@ export function stripStreamJson(stdout: string): string {
       // assistant message → extract text blocks
       if (msg.type === 'assistant' && msg.message?.content) {
         for (const block of msg.message.content) {
-          if (block.type === 'text' && block.text) textParts.push(block.text);
+          if (block.type === 'text' && block.text) assistantParts.push(block.text);
         }
       }
-      // result → extract result text
+      // result → the final answer (last one wins if several appear). Only a
+      // string result is authoritative; non-string payloads (objects) keep
+      // the old stringify-into-parts behavior instead of masking the
+      // assistant text with '{}'.
       else if (msg.type === 'result' && msg.result && !msg.is_error) {
-        textParts.push(typeof msg.result === 'string' ? msg.result : JSON.stringify(msg.result));
+        if (typeof msg.result === 'string') resultText = msg.result;
+        else assistantParts.push(JSON.stringify(msg.result));
       }
       // system, hook, etc. → skip
     } catch {
       // Not JSON — raw text from non-Claude engines, keep as-is
-      textParts.push(trimmed);
+      assistantParts.push(trimmed);
     }
   }
 
-  return textParts.join('\n');
+  return resultText.trim() ? resultText : assistantParts.join('\n');
 }
 
 /**
  * Check if engine exec mode outputs stream-json NDJSON.
  */
-// @kern-source: adapter-helpers:328
+// @kern-source: adapter-helpers:333
 export function usesStreamJson(engine: EngineDefinition): boolean {
   const args = engine.exec?.args ?? [];
   return args.includes('stream-json') || args.some((a: string) => a === '--output-format' && args[args.indexOf(a) + 1] === 'stream-json');
@@ -368,12 +373,12 @@ export function usesStreamJson(engine: EngineDefinition): boolean {
 /**
  * Only Codex-style JSON-RPC app-server is reliable for one-shot forge agent dispatch. Claude stream-json and Gemini ACP are reliable as persistent Cesar sessions, but the one-shot companion wrapper can hang or return empty, so forge should use their direct non-interactive CLI agent commands.
  */
-// @kern-source: adapter-helpers:334
+// @kern-source: adapter-helpers:339
 export function shouldUseCompanionForAgent(engine: EngineDefinition): boolean {
   return engine.companion?.protocol === 'jsonrpc';
 }
 
-// @kern-source: adapter-helpers:339
+// @kern-source: adapter-helpers:344
 export function checkEnvVars(engine: EngineDefinition): string|null {
   if (!engine.env) return null;
   for (const [envVar, config] of Object.entries(engine.env)) {
@@ -387,7 +392,7 @@ export function checkEnvVars(engine: EngineDefinition): string|null {
 /**
  * Drive `claude` via the kern-engines PTY subscription TUI? DEFAULT is now NO — claude dispatches via `claude --print` (-p), which Anthropic no longer meters under the subscription and is far more reliable than scraping the TUI. Opt back INTO the PTY brain with AGON_CLAUDE_PTY=1 / `agon config claudeBackend pty` (single source of truth: claudeBrainUsesPty). Claude is identified by id OR binary === 'claude' so this agrees with the persistent-session and cesar/session gates. cwd (when known) lets a project-local config override apply.
  */
-// @kern-source: adapter-helpers:350
+// @kern-source: adapter-helpers:355
 export function shouldUseClaudePty(engine: EngineDefinition, cwd?: string): boolean {
   if (engine.id !== 'claude' && engine.binary !== 'claude') {
     return false;
@@ -398,7 +403,7 @@ export function shouldUseClaudePty(engine: EngineDefinition, cwd?: string): bool
 /**
  * When a caller passed a systemPrompt, prepend it to the prompt with the same [System Instructions]/[User Message] framing the legacy non-flag CLI path uses. Claude's TUI has no --system-prompt equivalent we can apply through stdin, so this is the honest way to keep forge/tribunal/brainstorm system instructions intact on the pty path.
  */
-// @kern-source: adapter-helpers:357
+// @kern-source: adapter-helpers:362
 export function composeClaudePtyPrompt(prompt: string, systemPrompt?: string): string {
   if (!systemPrompt) return prompt;
   return `[System Instructions]\n${systemPrompt}\n\n[User Message]\n${prompt}`;
@@ -407,7 +412,7 @@ export function composeClaudePtyPrompt(prompt: string, systemPrompt?: string): s
 /**
  * Structured answer-channel transport for ONE-SHOT claude exec dispatch (council/forge/brainstorm/tribunal/synthesis members), bypassing the flaky TUI scrape. ON by default ('file' — claude writes its answer via its native Write tool to a temp file we read as authoritative). AGON_CLAUDE_ANSWER_CHANNEL: 'off'/'0'/'false' → off (raw scrape, for debugging); 'mcp' → the DeliverAnswer MCP variant (reserved); anything else (incl. unset) → 'file'. Never worse than the scrape — we fall back to it when claude doesn't deliver.
  */
-// @kern-source: adapter-helpers:364
+// @kern-source: adapter-helpers:369
 export function answerChannelMode(): string {
   const v = (process.env.AGON_CLAUDE_ANSWER_CHANNEL || '').trim().toLowerCase();
   if (v === 'off' || v === '0' || v === 'false') return 'off';
@@ -418,7 +423,7 @@ export function answerChannelMode(): string {
 /**
  * Whether the file answer-channel applies for a given one-shot dispatch mode. TRUE for both exec (council/forge/brainstorm/tribunal/synthesis members) AND agent (forge one-shot agent dispatch) — both lose long-form output to TUI scrape corruption and benefit from the authoritative file. Gated by answerChannelMode()==='file'. Defaults mode to 'exec'.
  */
-// @kern-source: adapter-helpers:373
+// @kern-source: adapter-helpers:378
 export function useFileChannelForMode(mode?: 'exec'|'agent'): boolean {
   const m = mode ?? 'exec';
   return (m === 'exec' || m === 'agent') && answerChannelMode() === 'file';
@@ -427,7 +432,7 @@ export function useFileChannelForMode(mode?: 'exec'|'agent'): boolean {
 /**
  * Appended to a one-shot claude prompt under file answer-channel mode: instruct claude to deliver its COMPLETE answer by writing it (markdown only, no commentary) to answerFile with its native Write tool. This is what makes the answer arrive as a clean file instead of a scraped TUI frame.
  */
-// @kern-source: adapter-helpers:380
+// @kern-source: adapter-helpers:385
 export function fileChannelInstruction(answerFile: string): string {
   return `\n\n---\n[ANSWER DELIVERY — REQUIRED] After composing your COMPLETE final answer, use your Write tool to write that answer — markdown only, no preamble, no commentary, nothing but the answer itself — to this exact file path:\n${answerFile}\nThat file is the ONLY channel by which your answer is captured. Write it exactly once, at the very end. Do NOT skip it.`;
 }
@@ -435,7 +440,7 @@ export function fileChannelInstruction(answerFile: string): string {
 /**
  * Read the authoritative answer a one-shot claude wrote to the channel file. Returns '' when the file is absent/empty (caller falls back to the scrape). Accepts raw markdown (file mode, native Write) OR a {text} JSON envelope (mcp mode, DeliverAnswer) transparently.
  */
-// @kern-source: adapter-helpers:386
+// @kern-source: adapter-helpers:391
 export function readAnswerChannelFile(answerFile: string): string {
   try {
     if (!existsSync(answerFile)) return '';
@@ -455,7 +460,7 @@ export function readAnswerChannelFile(answerFile: string): string {
 /**
  * Create a fresh temp dir + answer file for file-mode delivery and append the delivery instruction to the composed prompt. Returns the augmented prompt, the answer file path to read after the turn, and the dir to remove afterwards.
  */
-// @kern-source: adapter-helpers:404
+// @kern-source: adapter-helpers:409
 export function setupFileAnswerChannel(composed: string): { prompt:string, answerFile:string, dir:string } {
   const dir = mkdtempSync(join(tmpdir(), 'agon-ac-'));
   const answerFile = join(dir, 'answer.md');
@@ -465,7 +470,7 @@ export function setupFileAnswerChannel(composed: string): { prompt:string, answe
 /**
  * Drive interactive `claude` under a pty so the subscription billing path is used. Lazy-imports @kernlang/agon-engines — runs a python3 daemon (kern_engines.cli.daemon) over stdio JSON-RPC, no native node deps. cwd is plumbed through so worktree dispatches land in the right repo; systemPrompt is prepended to the prompt; extraArgv (model/effort launch flags) is forwarded to the engine exec. When AGON_CLAUDE_ANSWER_CHANNEL=file and mode is exec OR agent, claude is asked to Write its answer to a temp file we read as the AUTHORITATIVE result (clean — no TUI scrape), falling back to the scrape if the file is absent. Never throws — returns unavailable:true on any unexpected failure so kern callers can fall through to legacy paths with a simple !result.unavailable check.
  */
-// @kern-source: adapter-helpers:412
+// @kern-source: adapter-helpers:417
 export async function runClaudePtyDispatch(prompt: string, timeoutSec: number, signal?: AbortSignal, mode?: 'exec'|'agent', cwd?: string, systemPrompt?: string, env?: Record<string,string>, extraArgv?: string[]): Promise<{exitCode:number,stdout:string,stderr:string,durationMs:number,timedOut:boolean,unavailable?:boolean}> {
   const start = Date.now();
   try {
diff --git a/packages/adapter-cli/src/generated/adapter.ts b/packages/adapter-cli/src/generated/adapter.ts
index 9a53f5234..1e9943c9b 100644
--- a/packages/adapter-cli/src/generated/adapter.ts
+++ b/packages/adapter-cli/src/generated/adapter.ts
@@ -90,7 +90,7 @@ export class CliAdapter implements EngineAdapter {
     }
     // Try companion protocol (JSONRPC app-server) first — faster, more stable
     if (options.engine.companion) {
-      const companionResult = await companionDispatch({ config: options.engine.companion, binaryPath: binaryPath, prompt: options.prompt, cwd: options.cwd, timeout: options.timeout, mode: (options.mode === 'agent') ? 'agent' : ((options.mode === 'review') ? 'review' : 'exec'), model: resolveModel(options.engine, options.cwd) ?? undefined, signal: options.signal, systemPrompt: options.systemPrompt, env: iso.env });
+      const companionResult = await companionDispatch({ config: options.engine.companion, binaryPath: binaryPath, prompt: options.prompt, cwd: options.cwd, timeout: options.timeout, mode: (options.mode === 'agent') ? 'agent' : ((options.mode === 'review') ? 'review' : 'exec'), model: resolveModel(options.engine, options.cwd) ?? undefined, signal: options.signal, systemPrompt: options.systemPrompt, textOnly: options.textOnly, env: iso.env });
       // Exit code 2 = companion not available, fall through to CLI spawn
       // Also fall through if companion returned empty output (stream-json capture failure)
       if (companionResult.exitCode !== 2 && companionResult.stdout.trim()) {
diff --git a/packages/adapter-cli/src/kern/adapter-helpers.kern b/packages/adapter-cli/src/kern/adapter-helpers.kern
index 21f5d6c1e..bf4c14c8c 100644
--- a/packages/adapter-cli/src/kern/adapter-helpers.kern
+++ b/packages/adapter-cli/src/kern/adapter-helpers.kern
@@ -295,10 +295,11 @@ fn name=resolveAgentArgs params="engine:EngineDefinition, permissionLevel:'full'
   >>>
 
 fn name=stripStreamJson params="stdout:string" returns=string
-  doc "Extract text content from Claude stream-json NDJSON output. Returns plain text with system/hook messages removed."
+  doc "Extract text content from Claude stream-json NDJSON output. The final result event is the authoritative answer when present — concatenating it with the assistant text blocks duplicates the answer, and in multi-turn tool runs the early assistant texts are tool preambles ('I'll quickly verify...'), not the answer. Assistant texts remain the fallback for streams the result never closed (timeout kill, max-tokens is_error)."
   handler <<<
     const lines = stdout.split('\n');
-    const textParts: string[] = [];
+    const assistantParts: string[] = [];
+    let resultText = '';
 
     for (const line of lines) {
       const trimmed = line.trim();
@@ -308,21 +309,25 @@ fn name=stripStreamJson params="stdout:string" returns=string
         // assistant message → extract text blocks
         if (msg.type === 'assistant' && msg.message?.content) {
           for (const block of msg.message.content) {
-            if (block.type === 'text' && block.text) textParts.push(block.text);
+            if (block.type === 'text' && block.text) assistantParts.push(block.text);
           }
         }
-        // result → extract result text
+        // result → the final answer (last one wins if several appear). Only a
+        // string result is authoritative; non-string payloads (objects) keep
+        // the old stringify-into-parts behavior instead of masking the
+        // assistant text with '{}'.
         else if (msg.type === 'result' && msg.result && !msg.is_error) {
-          textParts.push(typeof msg.result === 'string' ? msg.result : JSON.stringify(msg.result));
+          if (typeof msg.result === 'string') resultText = msg.result;
+          else assistantParts.push(JSON.stringify(msg.result));
         }
         // system, hook, etc. → skip
       } catch {
         // Not JSON — raw text from non-Claude engines, keep as-is
-        textParts.push(trimmed);
+        assistantParts.push(trimmed);
       }
     }
 
-    return textParts.join('\n');
+    return resultText.trim() ? resultText : assistantParts.join('\n');
   >>>
 
 fn name=usesStreamJson params="engine:EngineDefinition" returns=boolean
diff --git a/packages/adapter-cli/src/kern/adapter.kern b/packages/adapter-cli/src/kern/adapter.kern
index eb4f2fc9e..e7923ce27 100644
--- a/packages/adapter-cli/src/kern/adapter.kern
+++ b/packages/adapter-cli/src/kern/adapter.kern
@@ -75,7 +75,7 @@ service name=CliAdapter implements=EngineAdapter
           return value="ptyResult"
       comment raw="// Try companion protocol (JSONRPC app-server) first — faster, more stable"
       if cond="options.engine.companion"
-        let name=companionResult value="await companionDispatch({ config: options.engine.companion, binaryPath, prompt: options.prompt, cwd: options.cwd, timeout: options.timeout, mode: options.mode === 'agent' ? 'agent' : options.mode === 'review' ? 'review' : 'exec', model: resolveModel(options.engine, options.cwd) ?? undefined, signal: options.signal, systemPrompt: options.systemPrompt, env: iso.env, })"
+        let name=companionResult value="await companionDispatch({ config: options.engine.companion, binaryPath, prompt: options.prompt, cwd: options.cwd, timeout: options.timeout, mode: options.mode === 'agent' ? 'agent' : options.mode === 'review' ? 'review' : 'exec', model: resolveModel(options.engine, options.cwd) ?? undefined, signal: options.signal, systemPrompt: options.systemPrompt, textOnly: options.textOnly, env: iso.env, })"
         comment raw="// Exit code 2 = companion not available, fall through to CLI spawn"
         comment raw="// Also fall through if companion returned empty output (stream-json capture failure)"
         if cond="companionResult.exitCode !== 2 && companionResult.stdout.trim()"
diff --git a/packages/cli/src/commands/brainstorm.ts b/packages/cli/src/commands/brainstorm.ts
index 13dd48a46..39fba1289 100644
--- a/packages/cli/src/commands/brainstorm.ts
+++ b/packages/cli/src/commands/brainstorm.ts
@@ -32,6 +32,11 @@ export const brainstormCommand = defineCommand({
       description: 'Timeout in seconds',
       default: '120',
     },
+    style: {
+      type: 'string',
+      description: "'divergent' (default: seats get distinct stances, synthesis keeps 2-3 directions) or 'grounded' (convergent, file-path-anchored single answer)",
+      default: 'divergent',
+    },
     label: {
       type: 'string',
       description: 'Human-readable suffix baked into the run dir name (orchestrators: distinguish parallel runs without grep).',
@@ -53,6 +58,10 @@ export const brainstormCommand = defineCommand({
       ? args.engines.split(',').map((s) => s.trim())
       : filterDefaultOrchestrationEngines(registry.activeIds(config));
 
+    if (args.style !== 'divergent' && args.style !== 'grounded') {
+      throw new Error(`Unknown --style "${args.style}" — use 'divergent' or 'grounded'.`);
+    }
+
     if (args.quiet) process.env.AGON_QUIET = '1';
     const startedAt = new Date().toISOString();
     const { path: outputDir } = createRunDir({
@@ -64,6 +73,7 @@ export const brainstormCommand = defineCommand({
     if (!quiet) {
       header(`Brainstorm: ${args.question}`);
       info(`Engines: ${available.join(', ')}`);
+      info(`Style: ${args.style}`);
     }
 
     const seatState = new Map<string, { ok: boolean; detail: string }>();
@@ -72,6 +82,7 @@ export const brainstormCommand = defineCommand({
       result = await runBrainstorm({
         question: args.question,
         engines: available,
+        style: args.style,
         registry,
         adapter,
         timeout: parseInt(args.timeout, 10),
diff --git a/packages/core/src/generated/models/types.ts b/packages/core/src/generated/models/types.ts
index 439a0f941..41d3e44db 100644
--- a/packages/core/src/generated/models/types.ts
+++ b/packages/core/src/generated/models/types.ts
@@ -1,9 +1,5 @@
 // @generated by kern v4.5.0 — DO NOT EDIT. Source: src/kern/models/types.kern
 
-// @kern-source: types:531
-// @kern-source: types:532
-// @kern-source: types:533
-// @kern-source: types:534
 // @kern-source: types:535
 // @kern-source: types:536
 // @kern-source: types:537
@@ -37,6 +33,10 @@
 // @kern-source: types:565
 // @kern-source: types:566
 // @kern-source: types:567
+// @kern-source: types:568
+// @kern-source: types:569
+// @kern-source: types:570
+// @kern-source: types:571
 
 // @kern-source: types:1
 export type EngineMode = 'exec' | 'review' | 'agent';
@@ -87,16 +87,18 @@ export interface CompanionConfig {
   serverCmd: string[];
   sandbox?: 'read-only'|'workspace-write'|'danger-full-access';
   cwdArg?: string;
+  systemPromptFlag?: string;
+  textOnlyArgs?: string[];
   features?: {threadResume?:boolean, nativeReview?:boolean, structuredOutput?:boolean};
 }
 
-// @kern-source: types:36
+// @kern-source: types:38
 export interface CliModelEntry {
   id: string;
   name?: string;
 }
 
-// @kern-source: types:40
+// @kern-source: types:42
 export interface EngineCliModelConfig {
   default?: string;
   list?: CliModelEntry[];
@@ -106,7 +108,7 @@ export interface EngineCliModelConfig {
 /**
  * Proactive context-window management metadata for an engine's Cesar brain session. Engines WITHOUT this object get NO budget behavior — the pre-turn gate is inert (zero regression risk). Thresholds are fractions of the EFFECTIVE window (contextWindow minus reserveTokens). See token-estimator.kern / session-budget.kern.
  */
-// @kern-source: types:45
+// @kern-source: types:47
 export interface SessionBudget {
   contextWindow: number;
   reserveTokens?: number;
@@ -117,7 +119,7 @@ export interface SessionBudget {
   charsPerToken?: number;
 }
 
-// @kern-source: types:62
+// @kern-source: types:64
 export interface EngineDefinition {
   schemaVersion: 1|2|3;
   id: string;
@@ -152,7 +154,7 @@ export interface EngineDefinition {
   isolationHints?: {configEnv?:string, strictMcpArgs?:string[], personalPaths?:string[], authFiles?:string[], authMarker?:string, setupHint?:string, loginArgs?:string[], supportsProjectMcp?:boolean};
 }
 
-// @kern-source: types:100
+// @kern-source: types:102
 export interface DispatchOptions {
   engine: EngineDefinition;
   prompt: string;
@@ -164,6 +166,7 @@ export interface DispatchOptions {
   signal?: AbortSignal;
   images?: ImageAttachment[];
   systemPrompt?: string;
+  textOnly?: boolean;
   tools?: Array<{type:string,function:{name:string,description:string,parameters:Record<string,unknown>}}>;
   messages?: Array<{role:string,content:any,tool_calls?:any[],tool_call_id?:string}>;
   onApproval?: (tool:string, command:string, reason?:string) => Promise<boolean|string>;
@@ -178,7 +181,7 @@ export interface DispatchOptions {
 /**
  * Structured parts captured at stream time. Enables compaction to fold over typed data instead of parsing strings.
  */
-// @kern-source: types:126
+// @kern-source: types:130
 export interface DispatchResult {
   exitCode: number;
   stdout: string;
@@ -192,14 +195,14 @@ export interface DispatchResult {
   finishReason?: string;
 }
 
-// @kern-source: types:142
+// @kern-source: types:146
 export interface AgentDispatchResult extends DispatchResult {
   diff: string;
   diffLines: number;
   filesChanged: number;
 }
 
-// @kern-source: types:147
+// @kern-source: types:151
 export interface EngineAdapter {
   dispatch: (options:DispatchOptions)=>Promise<DispatchResult>;
   dispatchStream?: (options:DispatchOptions)=>AsyncGenerator<string, DispatchResult, void>;
@@ -209,7 +212,7 @@ export interface EngineAdapter {
   getVersion: (engine:EngineDefinition)=>Promise<string|null>;
 }
 
-// @kern-source: types:155
+// @kern-source: types:159
 export interface FitnessResult {
   pass: boolean;
   diffLines: number;
@@ -222,7 +225,7 @@ export interface FitnessResult {
   syntaxInvalidFiles?: string[];
 }
 
-// @kern-source: types:166
+// @kern-source: types:170
 export interface ScoreWeights {
   pass: number;
   quality: number;
@@ -231,7 +234,7 @@ export interface ScoreWeights {
   duration: number;
 }
 
-// @kern-source: types:173
+// @kern-source: types:177
 export interface ScoreComponents {
   passScore: number;
   qualityScore: number;
@@ -241,7 +244,7 @@ export interface ScoreComponents {
   composite: number;
 }
 
-// @kern-source: types:181
+// @kern-source: types:185
 export interface GlickoRating {
   mu: number;
   phi: number;
@@ -251,7 +254,7 @@ export interface GlickoRating {
   lastActive: string;
 }
 
-// @kern-source: types:189
+// @kern-source: types:193
 export interface EngineMeta {
   firstSeen: string;
   lastActive: string;
@@ -260,7 +263,7 @@ export interface EngineMeta {
   versions: string[];
 }
 
-// @kern-source: types:196
+// @kern-source: types:200
 export interface RatingRecord {
   global: Record<string,GlickoRating>;
   byMode: {forge:Record<string,GlickoRating>,brainstorm:Record<string,GlickoRating>,tribunal:Record<string,GlickoRating>,critique:Record<string,GlickoRating>};
@@ -269,7 +272,7 @@ export interface RatingRecord {
   lastUpdated: string;
 }
 
-// @kern-source: types:203
+// @kern-source: types:207
 export interface AgonConfig {
   debug?: boolean;
   timeout?: number;
@@ -508,7 +511,7 @@ export const DEFAULT_AGON_CONFIG: Required<AgonConfig> = {
   browserExtensionIds: [],
 };
 
-// @kern-source: types:397
+// @kern-source: types:401
 export interface ScoutBid {
   engineId: string;
   confidence: number;
@@ -519,7 +522,7 @@ export interface ScoutBid {
   needsCompetition: boolean;
 }
 
-// @kern-source: types:406
+// @kern-source: types:410
 export interface RoutingDecision {
   action: 'chat'|'build'|'pipeline'|'campfire'|'forge'|'brainstorm'|'tribunal'|'agent'|'team-agent';
   leadEngine: string;
@@ -531,14 +534,14 @@ export interface RoutingDecision {
   bids: ScoutBid[];
 }
 
-// @kern-source: types:416
+// @kern-source: types:420
 export interface CampfireMessage {
   engineId: string;
   content: string;
   isLead: boolean;
 }
 
-// @kern-source: types:421
+// @kern-source: types:425
 export interface ForgeOptions {
   task: string;
   fitnessCmd: string;
@@ -564,7 +567,7 @@ export interface ForgeOptions {
   synthEngine?: string;
 }
 
-// @kern-source: types:450
+// @kern-source: types:454
 export interface EngineResult {
   engineId: string;
   pass: boolean;
@@ -586,14 +589,14 @@ export interface EngineResult {
   syntaxInvalidFiles?: string[];
 }
 
-// @kern-source: types:470
+// @kern-source: types:474
 export interface SkippedEngine {
   engineId: string;
   status: string;
   reason?: string;
 }
 
-// @kern-source: types:475
+// @kern-source: types:479
 export interface DispatchMetric {
   engineId: string;
   phase: 'stage1'|'stage1-fallback'|'stage2-scout'|'stage2-scout-fallback'|'stage2-follower'|'stage2-fallback'|'synthesis'|'gauntlet';
@@ -607,7 +610,7 @@ export interface DispatchMetric {
   tokens?: {prompt:number, response:number, costUsd:number};
 }
 
-// @kern-source: types:487
+// @kern-source: types:491
 export interface ForgeManifest {
   forgeId: string;
   forgeDir: string;
@@ -639,7 +642,7 @@ export interface ForgeManifest {
   gauntlet?: GauntletResult;
 }
 
-// @kern-source: types:517
+// @kern-source: types:521
 export interface ConvergenceEntry {
   file: string;
   fn: string;
@@ -647,7 +650,7 @@ export interface ConvergenceEntry {
   reason: string;
 }
 
-// @kern-source: types:523
+// @kern-source: types:527
 export interface ForgeJudgment {
   winner: string;
   strengths: { engineId: string; category: string; reason: string }[];
@@ -658,7 +661,7 @@ export interface ForgeJudgment {
 
 export type ForgeEventType = 'baseline:start' | 'baseline:done' | 'stage1:start' | 'stage1:dispatch' | 'stage1:score' | 'stage1:accepted' | 'stage2:start' | 'stage2:dispatch' | 'stage2:score' | 'stage2:done' | 'engine:failed' | 'engine:worktree' | 'winner:determined' | 'forge:no-candidate-diff' | 'synthesis:start' | 'synthesis:critique' | 'synthesis:refine' | 'synthesis:score' | 'synthesis:done' | 'elo:update' | 'gauntlet:start' | 'gauntlet:breaker-dispatch' | 'gauntlet:breaker-done' | 'gauntlet:attack-landed' | 'gauntlet:repair-start' | 'gauntlet:repair-done' | 'gauntlet:corpus-save' | 'gauntlet:done' | 'forge:done' | 'forge:engine-skipped' | 'forge:already-satisfied' | 'forge:single-survivor' | 'forge:no-engines-available' | 'forge:fatal' | 'forge:auto-finalize' | 'forge:health-check-start' | 'forge:health-check-done';
 
-// @kern-source: types:530
+// @kern-source: types:534
 export interface ForgeEvent {
   type: ForgeEventType;
   engineId?: string;
@@ -707,7 +710,7 @@ export interface ForgeEventMap {
 
 export type ForgeEventCallback = (event: ForgeEvent) => void;
 
-// @kern-source: types:569
+// @kern-source: types:573
 export interface BrainstormBid {
   engineId: string;
   confidence: number;
@@ -716,26 +719,26 @@ export interface BrainstormBid {
   score?: number;
 }
 
-// @kern-source: types:576
+// @kern-source: types:580
 export interface BrainstormGroup {
   members: string[];
   representative: string;
   similarity: number;
 }
 
-// @kern-source: types:581
+// @kern-source: types:585
 export interface BrainstormDedupStatus {
   status: 'not-needed' | 'applied' | 'unavailable' | 'failed' | 'timed-out';
   detail?: string;
 }
 
-// @kern-source: types:585
+// @kern-source: types:589
 export interface BrainstormSynthesisStatus {
   status: 'completed' | 'fallback';
   detail?: string;
 }
 
-// @kern-source: types:592
+// @kern-source: types:596
 export interface PanelHealth {
   requested: number;
   responded: number;
@@ -744,7 +747,7 @@ export interface PanelHealth {
   banner: string | null;
 }
 
-// @kern-source: types:599
+// @kern-source: types:603
 export interface BrainstormResult {
   question: string;
   bids: BrainstormBid[];
@@ -756,7 +759,7 @@ export interface BrainstormResult {
   panelHealth?: PanelHealth;
 }
 
-// @kern-source: types:609
+// @kern-source: types:613
 export interface BreakerArtifact {
   engineId: string;
   testScript: string;
@@ -766,7 +769,7 @@ export interface BreakerArtifact {
   validated: boolean;
 }
 
-// @kern-source: types:617
+// @kern-source: types:621
 export interface GauntletResult {
   winnerId: string;
   breakerArtifacts: BreakerArtifact[];
@@ -779,7 +782,7 @@ export interface GauntletResult {
   patchPath?: string;
 }
 
-// @kern-source: types:628
+// @kern-source: types:632
 export interface CorpusEntry {
   forgeId: string;
   taskClass: TaskClass;
@@ -789,7 +792,7 @@ export interface CorpusEntry {
   pattern?: string;
 }
 
-// @kern-source: types:636
+// @kern-source: types:640
 export interface GapPattern {
   pattern: string;
   taskClass: TaskClass;
@@ -800,7 +803,7 @@ export interface GapPattern {
   skillPath?: string;
 }
 
-// @kern-source: types:645
+// @kern-source: types:649
 export interface Critique {
   file: string;
   lines: string;
@@ -808,5 +811,5 @@ export interface Critique {
   minimalFix: string;
 }
 
-// @kern-source: types:651
+// @kern-source: types:655
 export const DEFAULT_CONFIG: Required<AgonConfig> = DEFAULT_AGON_CONFIG;
diff --git a/packages/core/src/generated/sessions/companion-dispatch.ts b/packages/core/src/generated/sessions/companion-dispatch.ts
index 0553a6ef1..db4b40040 100644
--- a/packages/core/src/generated/sessions/companion-dispatch.ts
+++ b/packages/core/src/generated/sessions/companion-dispatch.ts
@@ -25,7 +25,7 @@ export interface CompanionResult {
 }
 
 // @kern-source: companion-dispatch:19
-export async function companionDispatch(opts: {config:CompanionConfig, binaryPath:string, prompt:string, cwd:string, timeout:number, mode:'exec'|'review'|'agent', model?:string, signal?:AbortSignal, systemPrompt?:string, env?:Record<string,string>, onApproval?:(tool:string, command:string, reason?:string)=>Promise<boolean|string>}): Promise<DispatchResult> {
+export async function companionDispatch(opts: {config:CompanionConfig, binaryPath:string, prompt:string, cwd:string, timeout:number, mode:'exec'|'review'|'agent', model?:string, signal?:AbortSignal, systemPrompt?:string, textOnly?:boolean, env?:Record<string,string>, onApproval?:(tool:string, command:string, reason?:string)=>Promise<boolean|string>}): Promise<DispatchResult> {
   if (opts.config.protocol !== 'jsonrpc' && opts.config.protocol !== 'acp' && opts.config.protocol !== 'stream-json') {
     return { exitCode: 2, stdout: '', stderr: `Protocol "${opts.config.protocol}" not supported for one-shot dispatch`, durationMs: 0, timedOut: false };
   }
@@ -61,7 +61,17 @@ export async function companionDispatch(opts: {config:CompanionConfig, binaryPat
   // honor it (no cwdArg).
   const serverArgs = opts.config.cwdArg
     ? [...opts.config.serverCmd, opts.config.cwdArg, opts.cwd]
-    : opts.config.serverCmd;
+    : [...opts.config.serverCmd];
+  // stream-json has no in-band system-prompt channel — without the flag the
+  // caller's systemPrompt (seat stances, "do NOT use tools") is silently dropped.
+  // ACP/JSONRPC forward the systemPrompt in-band (session/new, thread/start),
+  // so the argv flag applies ONLY to stream-json — never double-apply.
+  if (opts.config.protocol === 'stream-json' && opts.systemPrompt && opts.config.systemPromptFlag) {
+    serverArgs.push(opts.config.systemPromptFlag, opts.systemPrompt);
+  }
+  if (opts.textOnly && opts.config.textOnlyArgs?.length) {
+    serverArgs.push(...opts.config.textOnlyArgs);
+  }
   const proc = spawn(opts.binaryPath, serverArgs, {
     stdio: ['pipe', 'pipe', 'pipe'],
     cwd: opts.cwd,
@@ -84,6 +94,7 @@ export async function companionDispatch(opts: {config:CompanionConfig, binaryPat
   let lastAcpPushWasChunk = false;
   let turnCompleted: Record<string, unknown> | null = null;
   let turnError: Record<string, unknown> | null = null;
+  let sawToolUse = false;
   let threadId: string | null = null;
   let stdinError: Error | null = null;
 
@@ -234,6 +245,7 @@ export async function companionDispatch(opts: {config:CompanionConfig, binaryPat
       if (raw.type === 'assistant' && raw.message?.content) {
         for (const block of raw.message.content) {
           if (block.type === 'text' && block.text) agentMessages.push(block.text);
+          if (block.type === 'tool_use') sawToolUse = true;
         }
         if (raw.message.stop_reason) { turnCompleted = raw; }
       }
@@ -425,6 +437,26 @@ export async function companionDispatch(opts: {config:CompanionConfig, binaryPat
     }
 
     const text = agentMessages.join('\n\n');
+
+    // stream-json runs --max-turns 1: a tool call ends the ONLY turn, so
+    // whatever text preceded it is a preamble ("I'll quickly verify..."), not
+    // the answer. Return empty stdout so the adapter's existing empty-output
+    // fall-through retries via the plain CLI spawn (exec: --max-turns 10,
+    // review: --max-turns 50), which can finish the tool loop. Applies to
+    // exec AND review — review turns inherently want tools, so via companion
+    // they hit this truncation on nearly every dispatch (review consensus:
+    // codex/zai/kimi/minimax). Agent mode never routes stream-json companions
+    // (shouldUseCompanionForAgent). Preamble rides in stderr for diagnosability.
+    if (isStreamJson && (opts.mode === 'exec' || opts.mode === 'review') && sawToolUse) {
+      return {
+        exitCode: 0,
+        stdout: '',
+        stderr: `companion turn ended on tool_use (max-turns 1); falling back to CLI spawn. Preamble: ${text.slice(0, 300)}`,
+        durationMs: Date.now() - startTime,
+        timedOut: false,
+      };
+    }
+
     return {
       exitCode: 0,
       stdout: text,
diff --git a/packages/core/src/kern/models/types.kern b/packages/core/src/kern/models/types.kern
index 162710962..a6a42ce53 100644
--- a/packages/core/src/kern/models/types.kern
+++ b/packages/core/src/kern/models/types.kern
@@ -31,6 +31,8 @@ interface name=CompanionConfig
   field name=serverCmd type="string[]"
   field name=sandbox type="'read-only'|'workspace-write'|'danger-full-access'" optional=true
   field name=cwdArg type=string optional=true doc="Flag the companion server uses to set its working directory (e.g. opencode's '--cwd'). When set, companionDispatch appends [cwdArg, opts.cwd] to serverCmd so the server is PINNED to the worktree. Required for servers (opencode) that ignore the spawn cwd / attach to a shared server in the launch repo — relying on the spawn cwd alone leaked writes into the parent repo."
+  field name=systemPromptFlag type=string optional=true doc="Flag the companion server accepts for a system prompt (e.g. claude's '--system-prompt'). When set, companionDispatch appends [systemPromptFlag, opts.systemPrompt] to serverCmd. Without it the stream-json protocol has no in-band system-prompt channel and the caller's systemPrompt is silently DROPPED — which is how brainstorm seat instructions never reached claude."
+  field name=textOnlyArgs type="string[]" optional=true doc="Args that disable the server's tools for a plain-text answer (e.g. claude's ['--tools','']). Appended to serverCmd only when the dispatch sets textOnly. Needed because stream-json companions run --max-turns 1: a tool call ends the only turn, so the caller gets the pre-tool preamble instead of an answer."
   field name=features type="{threadResume?:boolean, nativeReview?:boolean, structuredOutput?:boolean}" optional=true
 
 interface name=CliModelEntry
@@ -109,6 +111,8 @@ interface name=DispatchOptions
   field name=signal type=AbortSignal optional=true
   field name=images type="ImageAttachment[]" optional=true
   field name=systemPrompt type=string optional=true
+  field name=textOnly type=boolean optional=true
+    doc "The caller wants a plain-text answer and the engine must not use tools (brainstorm seats/synthesis, tribunal, council — dispatches whose system prompts already say 'do NOT use tools'). On the companion path this appends the engine's CompanionConfig.textOnlyArgs (e.g. claude --tools '') so a --max-turns 1 turn is always the complete answer instead of a tool-use preamble. Never set it for dispatches that may legitimately need tools (agon ask, room work)."
   field name=tools type="Array<{type:string,function:{name:string,description:string,parameters:Record<string,unknown>}}>" optional=true
     doc "Native function-calling tool specs (OpenAI-function shape). When present AND the dispatch resolves to the API path (binary-less engine + usable key), the adapter sends them to the model's native tool API and returns any structured call in DispatchResult.parts. IGNORED on the CLI/companion paths — those engines use the in-prompt text-marker protocol. Lets the browser brain's ReAct loop get reliable native tool calls from API-only coding-plan engines that otherwise forget to emit the text marker (narrate-and-stop)."
   field name=messages type="Array<{role:string,content:any,tool_calls?:any[],tool_call_id?:string}>" optional=true
diff --git a/packages/core/src/kern/sessions/companion-dispatch.kern b/packages/core/src/kern/sessions/companion-dispatch.kern
index 49913ce14..c94ee2235 100644
--- a/packages/core/src/kern/sessions/companion-dispatch.kern
+++ b/packages/core/src/kern/sessions/companion-dispatch.kern
@@ -16,7 +16,7 @@ interface name=CompanionResult
   field name=fileChanges type="Array<{changes:unknown,status:string}>"
   field name=commands type="Array<{command:string,exitCode:number,output:string}>"
 
-fn name=companionDispatch async=true params="opts:{config:CompanionConfig, binaryPath:string, prompt:string, cwd:string, timeout:number, mode:'exec'|'review'|'agent', model?:string, signal?:AbortSignal, systemPrompt?:string, env?:Record<string,string>, onApproval?:(tool:string, command:string, reason?:string)=>Promise<boolean|string>}" returns="Promise<DispatchResult>"
+fn name=companionDispatch async=true params="opts:{config:CompanionConfig, binaryPath:string, prompt:string, cwd:string, timeout:number, mode:'exec'|'review'|'agent', model?:string, signal?:AbortSignal, systemPrompt?:string, textOnly?:boolean, env?:Record<string,string>, onApproval?:(tool:string, command:string, reason?:string)=>Promise<boolean|string>}" returns="Promise<DispatchResult>"
   handler <<<
     if (opts.config.protocol !== 'jsonrpc' && opts.config.protocol !== 'acp' && opts.config.protocol !== 'stream-json') {
       return { exitCode: 2, stdout: '', stderr: `Protocol "${opts.config.protocol}" not supported for one-shot dispatch`, durationMs: 0, timedOut: false };
@@ -53,7 +53,17 @@ fn name=companionDispatch async=true params="opts:{config:CompanionConfig, binar
     // honor it (no cwdArg).
     const serverArgs = opts.config.cwdArg
       ? [...opts.config.serverCmd, opts.config.cwdArg, opts.cwd]
-      : opts.config.serverCmd;
+      : [...opts.config.serverCmd];
+    // stream-json has no in-band system-prompt channel — without the flag the
+    // caller's systemPrompt (seat stances, "do NOT use tools") is silently dropped.
+    // ACP/JSONRPC forward the systemPrompt in-band (session/new, thread/start),
+    // so the argv flag applies ONLY to stream-json — never double-apply.
+    if (opts.config.protocol === 'stream-json' && opts.systemPrompt && opts.config.systemPromptFlag) {
+      serverArgs.push(opts.config.systemPromptFlag, opts.systemPrompt);
+    }
+    if (opts.textOnly && opts.config.textOnlyArgs?.length) {
+      serverArgs.push(...opts.config.textOnlyArgs);
+    }
     const proc = spawn(opts.binaryPath, serverArgs, {
       stdio: ['pipe', 'pipe', 'pipe'],
       cwd: opts.cwd,
@@ -76,6 +86,7 @@ fn name=companionDispatch async=true params="opts:{config:CompanionConfig, binar
     let lastAcpPushWasChunk = false;
     let turnCompleted: Record<string, unknown> | null = null;
     let turnError: Record<string, unknown> | null = null;
+    let sawToolUse = false;
     let threadId: string | null = null;
     let stdinError: Error | null = null;
 
@@ -226,6 +237,7 @@ fn name=companionDispatch async=true params="opts:{config:CompanionConfig, binar
         if (raw.type === 'assistant' && raw.message?.content) {
           for (const block of raw.message.content) {
             if (block.type === 'text' && block.text) agentMessages.push(block.text);
+            if (block.type === 'tool_use') sawToolUse = true;
           }
           if (raw.message.stop_reason) { turnCompleted = raw; }
         }
@@ -417,6 +429,26 @@ fn name=companionDispatch async=true params="opts:{config:CompanionConfig, binar
       }
 
       const text = agentMessages.join('\n\n');
+
+      // stream-json runs --max-turns 1: a tool call ends the ONLY turn, so
+      // whatever text preceded it is a preamble ("I'll quickly verify..."), not
+      // the answer. Return empty stdout so the adapter's existing empty-output
+      // fall-through retries via the plain CLI spawn (exec: --max-turns 10,
+      // review: --max-turns 50), which can finish the tool loop. Applies to
+      // exec AND review — review turns inherently want tools, so via companion
+      // they hit this truncation on nearly every dispatch (review consensus:
+      // codex/zai/kimi/minimax). Agent mode never routes stream-json companions
+      // (shouldUseCompanionForAgent). Preamble rides in stderr for diagnosability.
+      if (isStreamJson && (opts.mode === 'exec' || opts.mode === 'review') && sawToolUse) {
+        return {
+          exitCode: 0,
+          stdout: '',
+          stderr: `companion turn ended on tool_use (max-turns 1); falling back to CLI spawn. Preamble: ${text.slice(0, 300)}`,
+          durationMs: Date.now() - startTime,
+          timedOut: false,
+        };
+      }
+
       return {
         exitCode: 0,
         stdout: text,
diff --git a/packages/core/src/schemas/engine-schema.test.ts b/packages/core/src/schemas/engine-schema.test.ts
index 60071ebb0..51fb6155f 100644
--- a/packages/core/src/schemas/engine-schema.test.ts
+++ b/packages/core/src/schemas/engine-schema.test.ts
@@ -40,6 +40,28 @@ const completeEngine = {
   },
 } as const;
 
+describe('CompanionConfigSchema dispatch fields', () => {
+  // Regression: Zod strips unknown keys on parse. When these fields were added
+  // to CompanionConfig without the schema, registry-loaded claude.json silently
+  // lost them and the system-prompt/tool-disable behavior was inactive at
+  // runtime (review blocker, codex).
+  it('preserves systemPromptFlag and textOnlyArgs through validation', () => {
+    const result = validateEngineConfig({
+      ...completeEngine,
+      companion: {
+        protocol: 'stream-json',
+        serverCmd: ['--print', '--max-turns', '1'],
+        systemPromptFlag: '--system-prompt',
+        textOnlyArgs: ['--tools', ''],
+      },
+    }, 'companion-engine.json');
+    expect(result.ok).toBe(true);
+    if (!result.ok) return;
+    expect(result.data.companion?.systemPromptFlag).toBe('--system-prompt');
+    expect(result.data.companion?.textOnlyArgs).toEqual(['--tools', '']);
+  });
+});
+
 describe('EngineDefinitionSchema execution metadata', () => {
   it('retains every supported engine and API execution field', () => {
     const result = validateEngineConfig(completeEngine, 'complete-engine.json');
diff --git a/packages/core/src/schemas/engine-schema.ts b/packages/core/src/schemas/engine-schema.ts
index cf363e137..a401e6cda 100644
--- a/packages/core/src/schemas/engine-schema.ts
+++ b/packages/core/src/schemas/engine-schema.ts
@@ -67,6 +67,13 @@ export const CompanionConfigSchema = z.object({
   // worktree — required for servers that ignore the spawn cwd (otherwise their
   // writes leak into the launch repo).
   cwdArg: z.string().optional(),
+  // Flag for passing the caller's systemPrompt on the command line (claude
+  // `--system-prompt`). stream-json has no in-band system-prompt channel —
+  // without this the systemPrompt is silently dropped on that protocol.
+  systemPromptFlag: z.string().optional(),
+  // Args that disable the server's tools for a plain-text answer (claude
+  // `['--tools','']`). Appended only when the dispatch sets textOnly.
+  textOnlyArgs: z.array(z.string()).optional(),
   sandbox: z.enum(['read-only', 'workspace-write', 'danger-full-access']).optional(),
   features: z.object({
     threadResume: z.boolean().optional(),
diff --git a/packages/forge/src/generated/brainstorm.ts b/packages/forge/src/generated/brainstorm.ts
index c9c68b944..0e45c9ccd 100644
--- a/packages/forge/src/generated/brainstorm.ts
+++ b/packages/forge/src/generated/brainstorm.ts
@@ -32,7 +32,7 @@ export function calibrateConfidence(engineId: string, rawBid: number): number {
 }
 
 // @kern-source: brainstorm:22
-export function qualityScore(engineId: string, draft: KernDraft): number {
+export function structuralScore(draft: KernDraft, style?: string): number {
   let score = 0;
   if (draft.approach.length > 10) {
     score += 20;
@@ -45,32 +45,81 @@ export function qualityScore(engineId: string, draft: KernDraft): number {
   }
   score += Math.min(draft.steps.length, 7) * 5;
   score += Math.min(draft.tradeoffs.length, 5) * 5;
-  score += Math.min(draft.keyFiles.length, 5) * 3;
+  // keyFiles reward only outside divergent style — reframing drafts rarely name
+  // files, so counting them systematically buries every non-anchor stance.
+  if (style !== 'divergent') {
+    score += Math.min(draft.keyFiles.length, 5) * 3;
+  }
+  return score;
+}
+
+// @kern-source: brainstorm:39
+export function qualityScore(engineId: string, draft: KernDraft, style?: string): number {
+  let score = structuralScore(draft, style);
   // Use calibrated confidence, not raw self-report
   score += calibrateConfidence(engineId, draft.confidence) * 0.05;
   return score;
 }
 
-// @kern-source: brainstorm:38
-export function rankDrafts(drafts: {engineId:string, draft:KernDraft, raw:string, seat:SeatOutcome}[]): {engineId:string, draft:KernDraft, raw:string, seat:SeatOutcome}[] {
+// @kern-source: brainstorm:46
+export function rankDrafts(drafts: {engineId:string, draft:KernDraft, raw:string, seat:SeatOutcome}[], style?: string): {engineId:string, draft:KernDraft, raw:string, seat:SeatOutcome}[] {
   return [...drafts].sort((a, b) => {
-    const scoreA = qualityScore(a.engineId, a.draft);
-    const scoreB = qualityScore(b.engineId, b.draft);
+    const scoreA = qualityScore(a.engineId, a.draft, style);
+    const scoreB = qualityScore(b.engineId, b.draft, style);
     return scoreB - scoreA;
   });
 }
 
-// @kern-source: brainstorm:47
-export async function collectRankedDrafts(opts: {question:string, context?:string, engines:string[], registry:EngineRegistry, adapter:EngineAdapter, timeout:number, outputDir:string, signal?:AbortSignal, onEvent?:(event:{type:string,data?:Record<string,unknown>})=>void}): Promise<{ranked:{engineId:string, draft:KernDraft, raw:string, seat:SeatOutcome}[], outcomes:SeatOutcome[]}> {
+// @kern-source: brainstorm:55
+export function assignStances(engines: string[]): Map<string,string> {
+  const stances = [
+    'ANCHOR: give your single best, most direct answer to the question as asked.',
+    'CONTRARIAN: assume the approach the question implies (or the most obvious one) is wrong — argue for a fundamentally different one.',
+    'FIRST-PRINCIPLES: ignore the structure the question implies; restate the underlying problem in one line and re-derive a solution from scratch.',
+    'OUTSIDER: answer as a strong expert from a different domain would — import a pattern this field does not normally use here.',
+    'EXPANSIONIST: propose the most ambitious defensible version — what does this look like solved properly at 10x the scope?',
+    'WILDCARD: propose something deliberately unconventional that you can still defend technically.',
+  ];
+  // Shuffle per run: a fixed seat→stance mapping would hand the same engine
+  // the lowest-scoring stance every time and deflate its Glicko rating.
+  const pool = [...stances];
+  for (let i = pool.length - 1; i > 0; i--) {
+    const j = Math.floor(Math.random() * (i + 1));
+    [pool[i], pool[j]] = [pool[j], pool[i]];
+  }
+  const map = new Map<string, string>();
+  engines.forEach((id, i) => map.set(id, pool[i % pool.length]));
+  return map;
+}
+
+// @kern-source: brainstorm:77
+export async function collectRankedDrafts(opts: {question:string, context?:string, engines:string[], style?:string, registry:EngineRegistry, adapter:EngineAdapter, timeout:number, outputDir:string, signal?:AbortSignal, onEvent?:(event:{type:string,data?:Record<string,unknown>})=>void}): Promise<{ranked:{engineId:string, draft:KernDraft, raw:string, seat:SeatOutcome}[], outcomes:SeatOutcome[]}> {
   const draftPrompt = buildKernDraftPrompt({
     question: opts.question,
     context: opts.context,
     mode: 'brainstorm',
   });
 
+  // Divergent style: each seat gets a distinct stance so the panel actually
+  // spreads out instead of six engines converging on the stated framing.
+  // The stance rides in the system prompt — the protocol draft prompt stays
+  // byte-identical so the draft-block output contract is undisturbed.
+  const stances = opts.style === 'divergent' ? assignStances(opts.engines) : null;
+  const baseSystemPrompt = 'You are participating in a brainstorm. Respond directly with your analysis and approach. Do NOT use tools, do NOT read files, do NOT run commands. Just think and write your response as plain text.';
+
   const draftPromises = opts.engines.map(async (engineId: string) => {
     const engine = opts.registry.get(engineId);
     opts.onEvent?.({ type: 'brainstorm:seat-started', data: { engineId } });
+    const stance = stances?.get(engineId);
+    const systemPrompt = stance
+      ? [
+          baseSystemPrompt,
+          '',
+          `Your seat stance — ${stance}`,
+          'The question may be over-specified: treat its framing as one hypothesis about the underlying problem, not a hard constraint. If a better framing exists, say so in the reasoning field.',
+          'Express the stance entirely inside the draft block fields (approach/reasoning/tradeoffs/steps). Do not add any text outside the draft block.',
+        ].join('\n')
+      : baseSystemPrompt;
     // One auto-retry per seat (shorter timeout) — transient flake must not
     // silently shrink the promised panel. Whatever still fails gets reported
     // through the panel-health banner instead of vanishing into a 3/6 run.
@@ -78,7 +127,8 @@ export async function collectRankedDrafts(opts: {question:string, context?:strin
       engineId,
       engine,
       prompt: draftPrompt,
-      systemPrompt: 'You are participating in a brainstorm. Respond directly with your analysis and approach. Do NOT use tools, do NOT read files, do NOT run commands. Just think and write your response as plain text.',
+      systemPrompt,
+      textOnly: true,
       cwd: process.cwd(),
       mode: 'exec',
       timeout: opts.timeout,
@@ -100,10 +150,10 @@ export async function collectRankedDrafts(opts: {question:string, context?:strin
 
   const attempts = await Promise.all(draftPromises);
   const drafts = attempts.flatMap((attempt) => attempt.entry ? [attempt.entry] : []);
-  return { ranked: rankDrafts(drafts), outcomes: attempts.map((attempt) => attempt.seat) };
+  return { ranked: rankDrafts(drafts, opts.style), outcomes: attempts.map((attempt) => attempt.seat) };
 }
 
-// @kern-source: brainstorm:90
+// @kern-source: brainstorm:138
 export function scoutScore(bid: ScoutBid): number {
   let score = 0;
   // Confidence: 40% weight (0-40 points)
@@ -117,12 +167,12 @@ export function scoutScore(bid: ScoutBid): number {
   return score;
 }
 
-// @kern-source: brainstorm:103
+// @kern-source: brainstorm:151
 function warnBrainstorm(message: string): void {
   console.warn(message);
 }
 
-// @kern-source: brainstorm:108
+// @kern-source: brainstorm:156
 export async function runScout(opts: {question:string, context?:string, engines:string[], scoutCount?:number, registry:EngineRegistry, adapter:EngineAdapter, timeout:number, outputDir:string, signal?:AbortSignal}): Promise<{rankedBids:ScoutBid[], leadEngine:string, topConfidence:number, disagreementSpread:number}> {
   const count = opts.scoutCount ?? 2;
   // Filter quarantined engines BEFORE slicing, else a dead engine in the first
@@ -141,7 +191,7 @@ export async function runScout(opts: {question:string, context?:string, engines:
   return { rankedBids: bids, leadEngine: (bids.length > 0) ? bids[0].engineId : scouts[0], topConfidence: topConfidence, disagreementSpread: disagreementSpread };
 }
 
-// @kern-source: brainstorm:126
+// @kern-source: brainstorm:174
 export function fallbackParse(output: string): KernDraft {
   const stripped = output.replace(/\x60\x60\x60(?:json)?\s*/gi, '').replace(/\x60\x60\x60/g, '');
   let depth = 0;
@@ -182,9 +232,12 @@ export function fallbackParse(output: string): KernDraft {
   };
 }
 
-// @kern-source: brainstorm:167
-export async function runBrainstorm(opts: {question:string, context?:string, engines:string[], registry:EngineRegistry, adapter:EngineAdapter, timeout:number, outputDir:string, signal?:AbortSignal, onEvent?:(event:{type:string,data?:Record<string,unknown>})=>void}): Promise<BrainstormResult> {
+// @kern-source: brainstorm:215
+export async function runBrainstorm(opts: {question:string, context?:string, engines:string[], style?:string, registry:EngineRegistry, adapter:EngineAdapter, timeout:number, outputDir:string, signal?:AbortSignal, onEvent?:(event:{type:string,data?:Record<string,unknown>})=>void}): Promise<BrainstormResult> {
   const brainstormId = randomUUID().slice(0, 8);
+  // 'divergent' is the default: brainstorm exists to spread the panel out.
+  // 'grounded' restores the pre-stance behavior (convergent, file-path-anchored).
+  const style = opts.style === 'grounded' ? 'grounded' : 'divergent';
   // Cold-start: seed newly-dropped model versions from their predecessor before
   // bidding, so a new engine competes at its family's strength, not 1500.
   seedNewEnginesFromRegistry(opts.registry);
@@ -201,7 +254,7 @@ export async function runBrainstorm(opts: {question:string, context?:string, eng
     sessionType: 'brainstorm',
     outputDir: opts.outputDir,
   });
-  sidechain.log('brainstorm:init', undefined, { question: opts.question, engines: __engines });
+  sidechain.log('brainstorm:init', undefined, { question: opts.question, engines: __engines, style });
 
   const skippedOutcomes: SeatOutcome[] = __hc.skipped.map((s) => ({
     engineId: s.engineId,
@@ -220,6 +273,7 @@ export async function runBrainstorm(opts: {question:string, context?:string, eng
     question: opts.question,
     context: opts.context,
     engines: __engines,
+    style,
     registry: opts.registry,
     adapter: opts.adapter,
     timeout: opts.timeout,
@@ -239,7 +293,7 @@ export async function runBrainstorm(opts: {question:string, context?:string, eng
   const bids: BrainstormBid[] = ranked.map((d, i) => {
     const reasoning = d.draft.approach + (d.draft.reasoning ? ` — ${d.draft.reasoning}` : '');
     const approach = d.draft.steps.map((s: string, j: number) => `${j + 1}. ${s}`).join('\n');
-    const score = qualityScore(d.engineId, d.draft);
+    const score = qualityScore(d.engineId, d.draft, style);
     return {
       engineId: d.engineId,
       confidence: calibrateConfidence(d.engineId, d.draft.confidence),
@@ -283,16 +337,31 @@ export async function runBrainstorm(opts: {question:string, context?:string, eng
     return `## ${d.engineId} (confidence: ${d.draft.confidence}%)\nApproach: ${d.draft.approach}${d.draft.reasoning ? `\nReasoning: ${d.draft.reasoning}` : ''}${d.draft.tradeoffs?.length ? `\nTradeoffs: ${d.draft.tradeoffs.join('; ')}` : ''}${steps ? `\nSteps:\n${steps}` : ''}`;
   }).join('\n\n');
 
-  const expandPrompt = [
-    opts.question,
-    '',
-    `Multiple AI engines analyzed this. Here are ALL their drafts — synthesize the best parts from each into one comprehensive answer:`,
-    '',
-    allDrafts,
-    '',
-    'Now write the best possible answer by combining the strongest ideas from ALL drafts above. Don\'t just pick one — take the best parts from each.',
-    'Be specific and actionable. Include file paths where relevant.',
-  ].join('\n');
+  // Divergent synthesis must keep the spread visible: collapsing every draft
+  // into one merged answer would undo the stances one dispatch later. It still
+  // ends with a single recommendation so downstream automation has one
+  // decidable answer to act on.
+  const expandPrompt = style === 'divergent'
+    ? [
+        opts.question,
+        '',
+        `Multiple AI engines analyzed this from deliberately different stances. Here are ALL their drafts:`,
+        '',
+        allDrafts,
+        '',
+        'Present the 2-3 strongest DISTINCT directions from the drafts above — including at least one that challenges the framing of the original question. For each direction: the core idea, why it could win, and its main risk.',
+        'Then close with a single clear recommendation: which direction to take first and why.',
+      ].join('\n')
+    : [
+        opts.question,
+        '',
+        `Multiple AI engines analyzed this. Here are ALL their drafts — synthesize the best parts from each into one comprehensive answer:`,
+        '',
+        allDrafts,
+        '',
+        'Now write the best possible answer by combining the strongest ideas from ALL drafts above. Don\'t just pick one — take the best parts from each.',
+        'Be specific and actionable. Include file paths where relevant.',
+      ].join('\n');
 
   let response: string;
   let synthesis: {status:'completed' | 'fallback', detail?:string};
@@ -302,6 +371,7 @@ export async function runBrainstorm(opts: {question:string, context?:string, eng
       engine: winnerEngine,
       prompt: expandPrompt,
       systemPrompt: 'You are expanding on a winning brainstorm approach. Respond directly with your detailed analysis as plain text. Do NOT use tools, read files, or run commands.',
+      textOnly: true,
       cwd: process.cwd(),
       mode: 'exec',
       timeout: opts.timeout,
diff --git a/packages/forge/src/generated/campfire.ts b/packages/forge/src/generated/campfire.ts
index bc091662b..b40eafdc8 100644
--- a/packages/forge/src/generated/campfire.ts
+++ b/packages/forge/src/generated/campfire.ts
@@ -51,6 +51,7 @@ export async function runCampfire(opts: {topic:string,context?:string,engines:st
         engine: leadEngine,
         prompt: basePrompt,
         systemPrompt: 'You are in a campfire conversation. Respond directly with your thoughts as plain text. Do NOT use tools, read files, or run commands.',
+        textOnly: true,
         cwd,
         mode: 'exec',
         timeout,
@@ -82,6 +83,7 @@ export async function runCampfire(opts: {topic:string,context?:string,engines:st
             engine,
             prompt: observerPrompt,
             systemPrompt: 'You are in a campfire conversation. Respond directly with your thoughts as plain text. Do NOT use tools, read files, or run commands.',
+            textOnly: true,
             cwd,
             mode: 'exec',
             timeout,
@@ -109,6 +111,7 @@ export async function runCampfire(opts: {topic:string,context?:string,engines:st
           engine,
           prompt: basePrompt,
           systemPrompt: 'You are in a campfire conversation. Respond directly with your thoughts as plain text. Do NOT use tools, read files, or run commands.',
+          textOnly: true,
           cwd,
           mode: 'exec',
           timeout,
diff --git a/packages/forge/src/generated/council.ts b/packages/forge/src/generated/council.ts
index 0ff575433..361adc65e 100644
--- a/packages/forge/src/generated/council.ts
+++ b/packages/forge/src/generated/council.ts
@@ -302,7 +302,7 @@ export async function runCouncil(opts: CouncilOptions): Promise<CouncilResult> {
     try {
       const engine = registry.get(engineId);
       const result: DispatchResult = await adapter.dispatch({
-        engine, prompt, systemPrompt: sys, cwd, mode: 'exec', timeout: timeoutSec, outputDir, signal,
+        engine, prompt, systemPrompt: sys, textOnly: true, cwd, mode: 'exec', timeout: timeoutSec, outputDir, signal,
       });
       const raw = String(result.stdout ?? '').trim();
       const cleaned = raw.replace(/<think>[\s\S]*?<\/think>\s*/gi, '').trim();
diff --git a/packages/forge/src/generated/nero.ts b/packages/forge/src/generated/nero.ts
index 4fdc33406..48ccb524f 100644
--- a/packages/forge/src/generated/nero.ts
+++ b/packages/forge/src/generated/nero.ts
@@ -241,6 +241,7 @@ export async function runNero(opts: NeroOptions): Promise<NeroResult> {
           engine,
           prompt,
           systemPrompt: sysPrompt,
+          textOnly: true,
           cwd: opts.cwd ?? resolveWorkingDir(),
           mode: 'exec' as any,
           timeout: opts.timeout,
diff --git a/packages/forge/src/generated/seat-dispatch.ts b/packages/forge/src/generated/seat-dispatch.ts
index bc1f4b2e7..f3c00d715 100644
--- a/packages/forge/src/generated/seat-dispatch.ts
+++ b/packages/forge/src/generated/seat-dispatch.ts
@@ -33,13 +33,14 @@ export function classifySeatFailure(result: DispatchResult): 'timeout' | 'empty'
  * Dispatch one panel seat; on a transient failure (timeout/empty/error) retry ONCE with ~half the timeout (never longer than the first attempt). Never retries a user abort. opts.extract lets a mode keep its own text-extraction (e.g. tribunal's <think> salvage) — an extract throw counts as an 'empty' failure. The outcome note feeds the panel-health banner; detail preserves the underlying stderr/message so diagnosability survives the categorization.
  */
 // @kern-source: seat-dispatch:31
-export async function dispatchSeatWithRetry(adapter: EngineAdapter, opts: {engineId:string, engine:any, prompt:string, systemPrompt?:string, cwd:string, mode:string, timeout:number, outputDir:string, signal?:AbortSignal, extract?:(result:DispatchResult)=>string}): Promise<SeatOutcome> {
+export async function dispatchSeatWithRetry(adapter: EngineAdapter, opts: {engineId:string, engine:any, prompt:string, systemPrompt?:string, textOnly?:boolean, cwd:string, mode:string, timeout:number, outputDir:string, signal?:AbortSignal, extract?:(result:DispatchResult)=>string}): Promise<SeatOutcome> {
   const attemptOnce = async (timeoutSec: number): Promise<{ failure: 'timeout' | 'empty' | 'error' | null; text: string; detail: string; auth: boolean }> => {
     try {
       const result = await adapter.dispatch({
         engine: opts.engine,
         prompt: opts.prompt,
         systemPrompt: opts.systemPrompt,
+        textOnly: opts.textOnly,
         cwd: opts.cwd,
         mode: opts.mode,
         timeout: timeoutSec,
@@ -101,7 +102,7 @@ export async function dispatchSeatWithRetry(adapter: EngineAdapter, opts: {engin
 /**
  * Fold seat outcomes into the structured panel-health record + the one-line banner every surface must print when degraded ('panel degraded: codex timeout → retried OK; zai empty → dropped (5/6 responded)').
  */
-// @kern-source: seat-dispatch:98
+// @kern-source: seat-dispatch:99
 export function buildPanelHealth(outcomes: SeatOutcome[]): { requested: number; responded: number; degraded: boolean; notes: string[]; banner: string | null } {
   const requested = outcomes.length;
   const responded = outcomes.filter((o) => o.ok).length;
diff --git a/packages/forge/src/generated/synthesis-modus.ts b/packages/forge/src/generated/synthesis-modus.ts
index cee4ab148..173305c75 100644
--- a/packages/forge/src/generated/synthesis-modus.ts
+++ b/packages/forge/src/generated/synthesis-modus.ts
@@ -237,6 +237,7 @@ export async function runSynthesisModus(opts: SynthesisOptions): Promise<Synthes
         engine,
         prompt: buildSynthesisDraftPrompt(prompt),
         systemPrompt: 'You are participating in a synthesis competition. Produce your best independent draft. Do NOT use tools, read files, or run commands.',
+        textOnly: true,
         cwd,
         mode: 'exec',
         timeout,
@@ -277,6 +278,7 @@ export async function runSynthesisModus(opts: SynthesisOptions): Promise<Synthes
           engine,
           prompt: buildSynthesisSwapPrompt(prompt, fromId, original),
           systemPrompt: "You are improving another engine's draft in a synthesis competition. Produce a better version with a ## REASONING section. Do NOT use tools, read files, or run commands.",
+          textOnly: true,
           cwd,
           mode: 'exec',
           timeout,
@@ -315,6 +317,7 @@ export async function runSynthesisModus(opts: SynthesisOptions): Promise<Synthes
       engine: judgeEngine,
       prompt: buildSynthesisJudgePrompt(prompt, entries),
       systemPrompt: 'You are an impartial judge in a synthesis competition. Score entries and declare a winner. Do NOT use tools, read files, or run commands.',
+      textOnly: true,
       cwd,
       mode: 'review',
       timeout,
diff --git a/packages/forge/src/generated/thinking.ts b/packages/forge/src/generated/thinking.ts
index 582748c41..554f7f209 100644
--- a/packages/forge/src/generated/thinking.ts
+++ b/packages/forge/src/generated/thinking.ts
@@ -454,6 +454,7 @@ export async function runAdversarialCritique(opts: {problem:string, thoughts:Tho
       engine: critic,
       prompt,
       systemPrompt: 'You are an adversarial reviewer of a reasoning chain. Respond with terse, specific critique bullets only. Do NOT use tools, read files, or run commands.',
+      textOnly: true,
       cwd: opts.cwd ?? process.cwd(),
       mode: 'exec',
       timeout: opts.timeout,
@@ -471,7 +472,7 @@ export async function runAdversarialCritique(opts: {problem:string, thoughts:Tho
 /**
  * Run one sequential-thinking chain via a single structured dispatch, then ground, machine-validate, select the winning branch (tot only), and optionally run a second `critic` engine to adversarially attack the chain. Pure prompt-scaffold path so it works for engines with weak/absent adaptive thinking. cwd defaults to process.cwd() but callers (e.g. goal --cwd) should pass the target repo so dispatch + grounding resolve there. Returns a ThinkResult whose refinedSpec is the handoff to `agon goal`.
  */
-// @kern-source: thinking:439
+// @kern-source: thinking:440
 export async function runThinkChain(opts: {problem:string, strategy:string, engineId:string, registry:EngineRegistry, adapter:EngineAdapter, maxThoughts:number, branches?:number, critic?:string, timeout:number, outputDir:string, cwd?:string, ground:boolean, signal?:AbortSignal}): Promise<ThinkResult> {
   const strategy = isThinkStrategy(opts.strategy) ? opts.strategy : 'linear';
   const branches = Math.max(1, Math.min(opts.branches ?? 1, 8));
@@ -486,6 +487,7 @@ export async function runThinkChain(opts: {problem:string, strategy:string, engi
       engine,
       prompt,
       systemPrompt: 'You are a structured sequential reasoner. Output ONLY the JSON object requested. Do NOT use tools, read files, or run commands.',
+      textOnly: true,
       cwd,
       mode: 'exec',
       timeout: opts.timeout,
diff --git a/packages/forge/src/generated/tribunal.ts b/packages/forge/src/generated/tribunal.ts
index 341c39bcd..86d0c149a 100644
--- a/packages/forge/src/generated/tribunal.ts
+++ b/packages/forge/src/generated/tribunal.ts
@@ -177,6 +177,7 @@ export async function runTribunal(opts: {question:string, engines:string[], roun
         engine,
         prompt,
         systemPrompt: 'You are a debate participant. Respond directly with your argument as plain text. Do NOT use tools, read files, or run commands.',
+        textOnly: true,
         cwd: process.cwd(),
         mode: 'exec',
         timeout,
@@ -245,6 +246,7 @@ export async function runTribunal(opts: {question:string, engines:string[], roun
       engine: summaryEngine,
       prompt: summaryPrompt,
       systemPrompt: 'You are synthesizing a debate. Respond directly with your verdict as plain text. Do NOT use tools, read files, or run commands.',
+      textOnly: true,
       cwd: process.cwd(),
       mode: 'exec',
       timeout,
diff --git a/packages/forge/src/kern/brainstorm.kern b/packages/forge/src/kern/brainstorm.kern
index 52e551712..8024c9670 100644
--- a/packages/forge/src/kern/brainstorm.kern
+++ b/packages/forge/src/kern/brainstorm.kern
@@ -19,7 +19,7 @@ fn name=calibrateConfidence params="engineId:string, rawBid:number" returns=numb
     comment raw="// Blend: 30% self-reported, 70% track record"
     return value="Math.round(rawBid * 0.3 + winRate * 100 * 0.7)"
 
-fn name=qualityScore params="engineId:string, draft:KernDraft" returns="number"
+fn name=structuralScore params="draft:KernDraft, style?:string" returns="number"
   handler lang="kern"
     let name=score kind=let value="0"
     if cond="draft.approach.length > 10"
@@ -30,21 +30,51 @@ fn name=qualityScore params="engineId:string, draft:KernDraft" returns="number"
       assign target="score" op="+=" value="15"
     assign target="score" op="+=" value="Math.min(draft.steps.length, 7) * 5"
     assign target="score" op="+=" value="Math.min(draft.tradeoffs.length, 5) * 5"
-    assign target="score" op="+=" value="Math.min(draft.keyFiles.length, 5) * 3"
+    comment raw="// keyFiles reward only outside divergent style — reframing drafts rarely name"
+    comment raw="// files, so counting them systematically buries every non-anchor stance."
+    if cond="style !== 'divergent'"
+      assign target="score" op="+=" value="Math.min(draft.keyFiles.length, 5) * 3"
+    return value="score"
+
+fn name=qualityScore params="engineId:string, draft:KernDraft, style?:string" returns="number"
+  handler lang="kern"
+    let name=score kind=let value="structuralScore(draft, style)"
     comment raw="// Use calibrated confidence, not raw self-report"
     assign target="score" op="+=" value="calibrateConfidence(engineId, draft.confidence) * 0.05"
     return value="score"
 
-fn name=rankDrafts params="drafts:{engineId:string, draft:KernDraft, raw:string, seat:SeatOutcome}[]" returns="{engineId:string, draft:KernDraft, raw:string, seat:SeatOutcome}[]"
+fn name=rankDrafts params="drafts:{engineId:string, draft:KernDraft, raw:string, seat:SeatOutcome}[], style?:string" returns="{engineId:string, draft:KernDraft, raw:string, seat:SeatOutcome}[]"
   handler <<<
     return [...drafts].sort((a, b) => {
-      const scoreA = qualityScore(a.engineId, a.draft);
-      const scoreB = qualityScore(b.engineId, b.draft);
+      const scoreA = qualityScore(a.engineId, a.draft, style);
+      const scoreB = qualityScore(b.engineId, b.draft, style);
       return scoreB - scoreA;
     });
   >>>
 
-fn name=collectRankedDrafts async=true params="opts:{question:string, context?:string, engines:string[], registry:EngineRegistry, adapter:EngineAdapter, timeout:number, outputDir:string, signal?:AbortSignal, onEvent?:(event:{type:string,data?:Record<string,unknown>})=>void}" returns="Promise<{ranked:{engineId:string, draft:KernDraft, raw:string, seat:SeatOutcome}[], outcomes:SeatOutcome[]}>"
+fn name=assignStances params="engines:string[]" returns="Map<string,string>"
+  handler <<<
+    const stances = [
+      'ANCHOR: give your single best, most direct answer to the question as asked.',
+      'CONTRARIAN: assume the approach the question implies (or the most obvious one) is wrong — argue for a fundamentally different one.',
+      'FIRST-PRINCIPLES: ignore the structure the question implies; restate the underlying problem in one line and re-derive a solution from scratch.',
+      'OUTSIDER: answer as a strong expert from a different domain would — import a pattern this field does not normally use here.',
+      'EXPANSIONIST: propose the most ambitious defensible version — what does this look like solved properly at 10x the scope?',
+      'WILDCARD: propose something deliberately unconventional that you can still defend technically.',
+    ];
+    // Shuffle per run: a fixed seat→stance mapping would hand the same engine
+    // the lowest-scoring stance every time and deflate its Glicko rating.
+    const pool = [...stances];
+    for (let i = pool.length - 1; i > 0; i--) {
+      const j = Math.floor(Math.random() * (i + 1));
+      [pool[i], pool[j]] = [pool[j], pool[i]];
+    }
+    const map = new Map<string, string>();
+    engines.forEach((id, i) => map.set(id, pool[i % pool.length]));
+    return map;
+  >>>
+
+fn name=collectRankedDrafts async=true params="opts:{question:string, context?:string, engines:string[], style?:string, registry:EngineRegistry, adapter:EngineAdapter, timeout:number, outputDir:string, signal?:AbortSignal, onEvent?:(event:{type:string,data?:Record<string,unknown>})=>void}" returns="Promise<{ranked:{engineId:string, draft:KernDraft, raw:string, seat:SeatOutcome}[], outcomes:SeatOutcome[]}>"
   handler lang="ts" <<<
     const draftPrompt = buildKernDraftPrompt({
       question: opts.question,
@@ -52,9 +82,26 @@ fn name=collectRankedDrafts async=true params="opts:{question:string, context?:s
       mode: 'brainstorm',
     });
 
+    // Divergent style: each seat gets a distinct stance so the panel actually
+    // spreads out instead of six engines converging on the stated framing.
+    // The stance rides in the system prompt — the protocol draft prompt stays
+    // byte-identical so the draft-block output contract is undisturbed.
+    const stances = opts.style === 'divergent' ? assignStances(opts.engines) : null;
+    const baseSystemPrompt = 'You are participating in a brainstorm. Respond directly with your analysis and approach. Do NOT use tools, do NOT read files, do NOT run commands. Just think and write your response as plain text.';
+
     const draftPromises = opts.engines.map(async (engineId: string) => {
       const engine = opts.registry.get(engineId);
       opts.onEvent?.({ type: 'brainstorm:seat-started', data: { engineId } });
+      const stance = stances?.get(engineId);
+      const systemPrompt = stance
+        ? [
+            baseSystemPrompt,
+            '',
+            `Your seat stance — ${stance}`,
+            'The question may be over-specified: treat its framing as one hypothesis about the underlying problem, not a hard constraint. If a better framing exists, say so in the reasoning field.',
+            'Express the stance entirely inside the draft block fields (approach/reasoning/tradeoffs/steps). Do not add any text outside the draft block.',
+          ].join('\n')
+        : baseSystemPrompt;
       // One auto-retry per seat (shorter timeout) — transient flake must not
       // silently shrink the promised panel. Whatever still fails gets reported
       // through the panel-health banner instead of vanishing into a 3/6 run.
@@ -62,7 +109,8 @@ fn name=collectRankedDrafts async=true params="opts:{question:string, context?:s
         engineId,
         engine,
         prompt: draftPrompt,
-        systemPrompt: 'You are participating in a brainstorm. Respond directly with your analysis and approach. Do NOT use tools, do NOT read files, do NOT run commands. Just think and write your response as plain text.',
+        systemPrompt,
+        textOnly: true,
         cwd: process.cwd(),
         mode: 'exec',
         timeout: opts.timeout,
@@ -84,7 +132,7 @@ fn name=collectRankedDrafts async=true params="opts:{question:string, context?:s
 
     const attempts = await Promise.all(draftPromises);
     const drafts = attempts.flatMap((attempt) => attempt.entry ? [attempt.entry] : []);
-    return { ranked: rankDrafts(drafts), outcomes: attempts.map((attempt) => attempt.seat) };
+    return { ranked: rankDrafts(drafts, opts.style), outcomes: attempts.map((attempt) => attempt.seat) };
   >>>
 
 fn name=scoutScore params="bid:ScoutBid" returns=number
@@ -164,9 +212,12 @@ fn name=fallbackParse params="output:string" returns="KernDraft"
     };
   >>>
 
-fn name=runBrainstorm async=true params="opts:{question:string, context?:string, engines:string[], registry:EngineRegistry, adapter:EngineAdapter, timeout:number, outputDir:string, signal?:AbortSignal, onEvent?:(event:{type:string,data?:Record<string,unknown>})=>void}" returns="Promise<BrainstormResult>"
+fn name=runBrainstorm async=true params="opts:{question:string, context?:string, engines:string[], style?:string, registry:EngineRegistry, adapter:EngineAdapter, timeout:number, outputDir:string, signal?:AbortSignal, onEvent?:(event:{type:string,data?:Record<string,unknown>})=>void}" returns="Promise<BrainstormResult>"
   handler lang="ts" <<<
     const brainstormId = randomUUID().slice(0, 8);
+    // 'divergent' is the default: brainstorm exists to spread the panel out.
+    // 'grounded' restores the pre-stance behavior (convergent, file-path-anchored).
+    const style = opts.style === 'grounded' ? 'grounded' : 'divergent';
     // Cold-start: seed newly-dropped model versions from their predecessor before
     // bidding, so a new engine competes at its family's strength, not 1500.
     seedNewEnginesFromRegistry(opts.registry);
@@ -183,7 +234,7 @@ fn name=runBrainstorm async=true params="opts:{question:string, context?:string,
       sessionType: 'brainstorm',
       outputDir: opts.outputDir,
     });
-    sidechain.log('brainstorm:init', undefined, { question: opts.question, engines: __engines });
+    sidechain.log('brainstorm:init', undefined, { question: opts.question, engines: __engines, style });
 
     const skippedOutcomes: SeatOutcome[] = __hc.skipped.map((s) => ({
       engineId: s.engineId,
@@ -202,6 +253,7 @@ fn name=runBrainstorm async=true params="opts:{question:string, context?:string,
       question: opts.question,
       context: opts.context,
       engines: __engines,
+      style,
       registry: opts.registry,
       adapter: opts.adapter,
       timeout: opts.timeout,
@@ -221,7 +273,7 @@ fn name=runBrainstorm async=true params="opts:{question:string, context?:string,
     const bids: BrainstormBid[] = ranked.map((d, i) => {
       const reasoning = d.draft.approach + (d.draft.reasoning ? ` — ${d.draft.reasoning}` : '');
       const approach = d.draft.steps.map((s: string, j: number) => `${j + 1}. ${s}`).join('\n');
-      const score = qualityScore(d.engineId, d.draft);
+      const score = qualityScore(d.engineId, d.draft, style);
       return {
         engineId: d.engineId,
         confidence: calibrateConfidence(d.engineId, d.draft.confidence),
@@ -265,16 +317,31 @@ fn name=runBrainstorm async=true params="opts:{question:string, context?:string,
       return `## ${d.engineId} (confidence: ${d.draft.confidence}%)\nApproach: ${d.draft.approach}${d.draft.reasoning ? `\nReasoning: ${d.draft.reasoning}` : ''}${d.draft.tradeoffs?.length ? `\nTradeoffs: ${d.draft.tradeoffs.join('; ')}` : ''}${steps ? `\nSteps:\n${steps}` : ''}`;
     }).join('\n\n');
 
-    const expandPrompt = [
-      opts.question,
-      '',
-      `Multiple AI engines analyzed this. Here are ALL their drafts — synthesize the best parts from each into one comprehensive answer:`,
-      '',
-      allDrafts,
-      '',
-      'Now write the best possible answer by combining the strongest ideas from ALL drafts above. Don\'t just pick one — take the best parts from each.',
-      'Be specific and actionable. Include file paths where relevant.',
-    ].join('\n');
+    // Divergent synthesis must keep the spread visible: collapsing every draft
+    // into one merged answer would undo the stances one dispatch later. It still
+    // ends with a single recommendation so downstream automation has one
+    // decidable answer to act on.
+    const expandPrompt = style === 'divergent'
+      ? [
+          opts.question,
+          '',
+          `Multiple AI engines analyzed this from deliberately different stances. Here are ALL their drafts:`,
+          '',
+          allDrafts,
+          '',
+          'Present the 2-3 strongest DISTINCT directions from the drafts above — including at least one that challenges the framing of the original question. For each direction: the core idea, why it could win, and its main risk.',
+          'Then close with a single clear recommendation: which direction to take first and why.',
+        ].join('\n')
+      : [
+          opts.question,
+          '',
+          `Multiple AI engines analyzed this. Here are ALL their drafts — synthesize the best parts from each into one comprehensive answer:`,
+          '',
+          allDrafts,
+          '',
+          'Now write the best possible answer by combining the strongest ideas from ALL drafts above. Don\'t just pick one — take the best parts from each.',
+          'Be specific and actionable. Include file paths where relevant.',
+        ].join('\n');
 
     let response: string;
     let synthesis: {status:'completed' | 'fallback', detail?:string};
@@ -284,6 +351,7 @@ fn name=runBrainstorm async=true params="opts:{question:string, context?:string,
         engine: winnerEngine,
         prompt: expandPrompt,
         systemPrompt: 'You are expanding on a winning brainstorm approach. Respond directly with your detailed analysis as plain text. Do NOT use tools, read files, or run commands.',
+        textOnly: true,
         cwd: process.cwd(),
         mode: 'exec',
         timeout: opts.timeout,
diff --git a/packages/forge/src/kern/campfire.kern b/packages/forge/src/kern/campfire.kern
index 5176ce4d4..570e528f0 100644
--- a/packages/forge/src/kern/campfire.kern
+++ b/packages/forge/src/kern/campfire.kern
@@ -45,6 +45,7 @@ fn name=runCampfire async=true params="opts:{topic:string,context?:string,engine
           engine: leadEngine,
           prompt: basePrompt,
           systemPrompt: 'You are in a campfire conversation. Respond directly with your thoughts as plain text. Do NOT use tools, read files, or run commands.',
+          textOnly: true,
           cwd,
           mode: 'exec',
           timeout,
@@ -76,6 +77,7 @@ fn name=runCampfire async=true params="opts:{topic:string,context?:string,engine
               engine,
               prompt: observerPrompt,
               systemPrompt: 'You are in a campfire conversation. Respond directly with your thoughts as plain text. Do NOT use tools, read files, or run commands.',
+              textOnly: true,
               cwd,
               mode: 'exec',
               timeout,
@@ -103,6 +105,7 @@ fn name=runCampfire async=true params="opts:{topic:string,context?:string,engine
             engine,
             prompt: basePrompt,
             systemPrompt: 'You are in a campfire conversation. Respond directly with your thoughts as plain text. Do NOT use tools, read files, or run commands.',
+            textOnly: true,
             cwd,
             mode: 'exec',
             timeout,
diff --git a/packages/forge/src/kern/council.kern b/packages/forge/src/kern/council.kern
index 2ee440573..b693498ae 100644
--- a/packages/forge/src/kern/council.kern
+++ b/packages/forge/src/kern/council.kern
@@ -298,7 +298,7 @@ fn name=runCouncil async=true params="opts:CouncilOptions" returns="Promise<Coun
       try {
         const engine = registry.get(engineId);
         const result: DispatchResult = await adapter.dispatch({
-          engine, prompt, systemPrompt: sys, cwd, mode: 'exec', timeout: timeoutSec, outputDir, signal,
+          engine, prompt, systemPrompt: sys, textOnly: true, cwd, mode: 'exec', timeout: timeoutSec, outputDir, signal,
         });
         const raw = String(result.stdout ?? '').trim();
         const cleaned = raw.replace(/<think>[\s\S]*?<\/think>\s*/gi, '').trim();
diff --git a/packages/forge/src/kern/nero.kern b/packages/forge/src/kern/nero.kern
index 7bd21ef8a..eb0fdaf70 100644
--- a/packages/forge/src/kern/nero.kern
+++ b/packages/forge/src/kern/nero.kern
@@ -234,6 +234,7 @@ fn name=runNero async=true params="opts:NeroOptions" returns="Promise<NeroResult
             engine,
             prompt,
             systemPrompt: sysPrompt,
+            textOnly: true,
             cwd: opts.cwd ?? resolveWorkingDir(),
             mode: 'exec' as any,
             timeout: opts.timeout,
diff --git a/packages/forge/src/kern/seat-dispatch.kern b/packages/forge/src/kern/seat-dispatch.kern
index afb03efb5..7116b5d88 100644
--- a/packages/forge/src/kern/seat-dispatch.kern
+++ b/packages/forge/src/kern/seat-dispatch.kern
@@ -28,7 +28,7 @@ fn name=classifySeatFailure params="result:DispatchResult" returns="'timeout' |
     return null;
   >>>
 
-fn name=dispatchSeatWithRetry async=true params="adapter:EngineAdapter, opts:{engineId:string, engine:any, prompt:string, systemPrompt?:string, cwd:string, mode:string, timeout:number, outputDir:string, signal?:AbortSignal, extract?:(result:DispatchResult)=>string}" returns="Promise<SeatOutcome>" export=true
+fn name=dispatchSeatWithRetry async=true params="adapter:EngineAdapter, opts:{engineId:string, engine:any, prompt:string, systemPrompt?:string, textOnly?:boolean, cwd:string, mode:string, timeout:number, outputDir:string, signal?:AbortSignal, extract?:(result:DispatchResult)=>string}" returns="Promise<SeatOutcome>" export=true
   doc "Dispatch one panel seat; on a transient failure (timeout/empty/error) retry ONCE with ~half the timeout (never longer than the first attempt). Never retries a user abort. opts.extract lets a mode keep its own text-extraction (e.g. tribunal's <think> salvage) — an extract throw counts as an 'empty' failure. The outcome note feeds the panel-health banner; detail preserves the underlying stderr/message so diagnosability survives the categorization."
   handler <<<
     const attemptOnce = async (timeoutSec: number): Promise<{ failure: 'timeout' | 'empty' | 'error' | null; text: string; detail: string; auth: boolean }> => {
@@ -37,6 +37,7 @@ fn name=dispatchSeatWithRetry async=true params="adapter:EngineAdapter, opts:{en
           engine: opts.engine,
           prompt: opts.prompt,
           systemPrompt: opts.systemPrompt,
+          textOnly: opts.textOnly,
           cwd: opts.cwd,
           mode: opts.mode,
           timeout: timeoutSec,
diff --git a/packages/forge/src/kern/synthesis-modus.kern b/packages/forge/src/kern/synthesis-modus.kern
index f2a302da8..9d5bc69e0 100644
--- a/packages/forge/src/kern/synthesis-modus.kern
+++ b/packages/forge/src/kern/synthesis-modus.kern
@@ -223,6 +223,7 @@ fn name=runSynthesisModus async=true params="opts:SynthesisOptions" returns="Pro
           engine,
           prompt: buildSynthesisDraftPrompt(prompt),
           systemPrompt: 'You are participating in a synthesis competition. Produce your best independent draft. Do NOT use tools, read files, or run commands.',
+          textOnly: true,
           cwd,
           mode: 'exec',
           timeout,
@@ -263,6 +264,7 @@ fn name=runSynthesisModus async=true params="opts:SynthesisOptions" returns="Pro
             engine,
             prompt: buildSynthesisSwapPrompt(prompt, fromId, original),
             systemPrompt: "You are improving another engine's draft in a synthesis competition. Produce a better version with a ## REASONING section. Do NOT use tools, read files, or run commands.",
+            textOnly: true,
             cwd,
             mode: 'exec',
             timeout,
@@ -301,6 +303,7 @@ fn name=runSynthesisModus async=true params="opts:SynthesisOptions" returns="Pro
         engine: judgeEngine,
         prompt: buildSynthesisJudgePrompt(prompt, entries),
         systemPrompt: 'You are an impartial judge in a synthesis competition. Score entries and declare a winner. Do NOT use tools, read files, or run commands.',
+        textOnly: true,
         cwd,
         mode: 'review',
         timeout,
diff --git a/packages/forge/src/kern/thinking.kern b/packages/forge/src/kern/thinking.kern
index 75fde7a27..d1b049d8d 100644
--- a/packages/forge/src/kern/thinking.kern
+++ b/packages/forge/src/kern/thinking.kern
@@ -420,6 +420,7 @@ fn name=runAdversarialCritique async=true params="opts:{problem:string, thoughts
         engine: critic,
         prompt,
         systemPrompt: 'You are an adversarial reviewer of a reasoning chain. Respond with terse, specific critique bullets only. Do NOT use tools, read files, or run commands.',
+        textOnly: true,
         cwd: opts.cwd ?? process.cwd(),
         mode: 'exec',
         timeout: opts.timeout,
@@ -452,6 +453,7 @@ fn name=runThinkChain async=true params="opts:{problem:string, strategy:string,
         engine,
         prompt,
         systemPrompt: 'You are a structured sequential reasoner. Output ONLY the JSON object requested. Do NOT use tools, read files, or run commands.',
+        textOnly: true,
         cwd,
         mode: 'exec',
         timeout: opts.timeout,
diff --git a/packages/forge/src/kern/tribunal.kern b/packages/forge/src/kern/tribunal.kern
index 41ae3eb2f..211c39ab8 100644
--- a/packages/forge/src/kern/tribunal.kern
+++ b/packages/forge/src/kern/tribunal.kern
@@ -159,6 +159,7 @@ fn name=runTribunal async=true params="opts:{question:string, engines:string[],
           engine,
           prompt,
           systemPrompt: 'You are a debate participant. Respond directly with your argument as plain text. Do NOT use tools, read files, or run commands.',
+          textOnly: true,
           cwd: process.cwd(),
           mode: 'exec',
           timeout,
@@ -227,6 +228,7 @@ fn name=runTribunal async=true params="opts:{question:string, engines:string[],
         engine: summaryEngine,
         prompt: summaryPrompt,
         systemPrompt: 'You are synthesizing a debate. Respond directly with your verdict as plain text. Do NOT use tools, read files, or run commands.',
+        textOnly: true,
         cwd: process.cwd(),
         mode: 'exec',
         timeout,
diff --git a/packages/forge/test/kern/brainstorm.test.kern b/packages/forge/test/kern/brainstorm.test.kern
new file mode 100644
index 000000000..3937b3636
--- /dev/null
+++ b/packages/forge/test/kern/brainstorm.test.kern
@@ -0,0 +1,11 @@
+test name="Brainstorm divergence contracts" target="../../src/kern/brainstorm.kern"
+  it name="brainstorm source stays valid KERN"
+    expect no=schemaViolations
+    expect no=semanticViolations
+    expect no=codegenErrors
+
+  it name="grounded style rewards keyFiles"
+    expect fn=structuralScore args={{[{"approach": "use a message queue to decouple the pipeline", "reasoning": "reduces coupling", "tradeoffs": ["latency", "ops burden"], "confidence": 50, "keyFiles": ["src/a.ts", "src/b.ts"], "steps": ["one", "two", "three"]}, "grounded"]}} equals=76
+
+  it name="divergent style drops the keyFiles reward so reframing drafts are not buried"
+    expect fn=structuralScore args={{[{"approach": "use a message queue to decouple the pipeline", "reasoning": "reduces coupling", "tradeoffs": ["latency", "ops burden"], "confidence": 50, "keyFiles": ["src/a.ts", "src/b.ts"], "steps": ["one", "two", "three"]}, "divergent"]}} equals=70
diff --git a/tests/unit/brainstorm-style.test.ts b/tests/unit/brainstorm-style.test.ts
new file mode 100644
index 000000000..0a620f62a
--- /dev/null
+++ b/tests/unit/brainstorm-style.test.ts
@@ -0,0 +1,141 @@
+import { describe, it, expect } from 'vitest';
+import { mkdtempSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { join } from 'node:path';
+import { assignStances, collectRankedDrafts, runBrainstorm } from '../../packages/forge/src/generated/brainstorm.js';
+
+const STANCE_LABELS = ['ANCHOR', 'CONTRARIAN', 'FIRST-PRINCIPLES', 'OUTSIDER', 'EXPANSIONIST', 'WILDCARD'];
+
+const DRAFT_BLOCK = `draft {
+  approach: "use a message queue to decouple the pipeline"
+  reasoning: "reduces coupling between stages"
+  tradeoffs: "latency", "ops burden"
+  confidence: 70
+  keyFiles: "src/a.ts"
+  steps {
+    1: "one"
+    2: "two"
+    3: "three"
+  }
+}`;
+
+function makeFakes() {
+  const calls: { engineId: string; prompt: string; systemPrompt?: string; textOnly?: boolean }[] = [];
+  const adapter = {
+    dispatch: async (o: any) => {
+      calls.push({ engineId: o.engine?.id, prompt: o.prompt, systemPrompt: o.systemPrompt, textOnly: o.textOnly });
+      return { exitCode: 0, stdout: DRAFT_BLOCK, stderr: '', timedOut: false };
+    },
+  } as any;
+  const registry = {
+    get: (id: string) => ({ id, binary: id }),
+    list: () => [],
+    findBinary: () => null,
+  } as any;
+  return { calls, adapter, registry };
+}
+
+const SIX_ENGINES = ['e1', 'e2', 'e3', 'e4', 'e5', 'e6'];
+
+function baseOpts(overrides: Record<string, unknown> = {}) {
+  const { calls, adapter, registry } = makeFakes();
+  return {
+    calls,
+    opts: {
+      question: 'how should we cache?',
+      engines: SIX_ENGINES,
+      registry,
+      adapter,
+      timeout: 5,
+      outputDir: mkdtempSync(join(tmpdir(), 'agon-brainstorm-style-')),
+      ...overrides,
+    },
+  };
+}
+
+describe('brainstorm divergent style', () => {
+  describe('assignStances', () => {
+    it('gives every engine exactly one stance from the known set', () => {
+      const map = assignStances(SIX_ENGINES);
+      expect(map.size).toBe(6);
+      for (const id of SIX_ENGINES) {
+        const stance = map.get(id)!;
+        expect(STANCE_LABELS.some((label) => stance.startsWith(`${label}:`))).toBe(true);
+      }
+    });
+
+    it('uses all six distinct stances for a six-engine panel', () => {
+      const map = assignStances(SIX_ENGINES);
+      expect(new Set(map.values()).size).toBe(6);
+    });
+
+    it('cycles stances when the panel is larger than the stance pool', () => {
+      const engines = [...SIX_ENGINES, 'e7', 'e8'];
+      const map = assignStances(engines);
+      expect(map.size).toBe(8);
+      for (const id of engines) expect(map.get(id)).toBeTruthy();
+    });
+  });
+
+  describe('collectRankedDrafts stance injection', () => {
+    it('divergent style: each seat gets a distinct stance in the system prompt, user prompt stays identical and stance-free', async () => {
+      const { calls, opts } = baseOpts({ style: 'divergent' });
+      await collectRankedDrafts(opts as any);
+      expect(calls.length).toBe(6);
+      const stanceLines = calls.map((c) => c.systemPrompt ?? '');
+      for (const sp of stanceLines) {
+        expect(sp).toContain('Your seat stance —');
+        expect(sp).toContain('one hypothesis about the underlying problem');
+        expect(sp).toContain('Do not add any text outside the draft block');
+      }
+      expect(new Set(stanceLines).size).toBe(6);
+      // Protocol draft prompt must stay byte-identical across seats — the
+      // stance rides ONLY in the system prompt.
+      expect(new Set(calls.map((c) => c.prompt)).size).toBe(1);
+      expect(calls[0].prompt).not.toContain('seat stance');
+    });
+
+    it('grounded/absent style: system prompt is the plain brainstorm instruction with no stance', async () => {
+      const { calls, opts } = baseOpts();
+      await collectRankedDrafts(opts as any);
+      expect(calls.length).toBe(6);
+      for (const c of calls) {
+        expect(c.systemPrompt).not.toContain('seat stance');
+        expect(c.systemPrompt).toContain('You are participating in a brainstorm');
+      }
+    });
+  });
+
+  describe('runBrainstorm style dispatch + synthesis prompt', () => {
+    async function synthesisPromptFor(style?: string) {
+      const { calls, opts } = baseOpts(style ? { style } : {});
+      await runBrainstorm(opts as any);
+      const synthesis = calls.filter((c) => c.prompt.includes('Multiple AI engines analyzed'));
+      expect(synthesis.length).toBe(1);
+      return synthesis[0].prompt;
+    }
+
+    it('defaults to divergent: synthesis keeps distinct directions and one closing recommendation', async () => {
+      const prompt = await synthesisPromptFor();
+      expect(prompt).toContain('deliberately different stances');
+      expect(prompt).toContain('DISTINCT directions');
+      expect(prompt).toContain('challenges the framing');
+      expect(prompt).toContain('single clear recommendation');
+      expect(prompt).not.toContain('Include file paths where relevant');
+    });
+
+    it('grounded style restores the convergent synthesis prompt', async () => {
+      const prompt = await synthesisPromptFor('grounded');
+      expect(prompt).toContain('synthesize the best parts from each into one comprehensive answer');
+      expect(prompt).toContain('Be specific and actionable. Include file paths where relevant.');
+      expect(prompt).not.toContain('DISTINCT directions');
+    });
+
+    it('marks every seat and the synthesis dispatch textOnly so engines cannot burn the turn on tools', async () => {
+      const { calls, opts } = baseOpts();
+      await runBrainstorm(opts as any);
+      expect(calls.length).toBeGreaterThan(0);
+      for (const c of calls) expect(c.textOnly).toBe(true);
+    });
+  });
+});
diff --git a/tests/unit/companion-dispatch.test.ts b/tests/unit/companion-dispatch.test.ts
index 18c089480..8ac916147 100644
--- a/tests/unit/companion-dispatch.test.ts
+++ b/tests/unit/companion-dispatch.test.ts
@@ -45,6 +45,96 @@ describe('companionDispatch', () => {
     expect(Date.now() - startedAt).toBeLessThan(3000);
   });
 
+  it('forwards the system prompt via systemPromptFlag on the stream-json path', async () => {
+    // Fake server echoes its argv back as the result — proves the flag+prompt
+    // landed on the command line (stream-json has no in-band system-prompt channel).
+    // The '--' keeps node from eating the appended flags as node options; the
+    // interval keeps stdin writable until dispatch teardown kills the process.
+    const script = "process.stdout.write(JSON.stringify({ type: 'result', result: process.argv.slice(1).join(' ') }) + '\\n'); setInterval(() => {}, 1000);";
+    const result = await companionDispatch({
+      binaryPath: process.execPath,
+      config: {
+        protocol: 'stream-json',
+        serverCmd: ['-e', script, '--'],
+        systemPromptFlag: '--system-prompt',
+      },
+      prompt: 'hello',
+      cwd: process.cwd(),
+      timeout: 5,
+      mode: 'exec',
+      systemPrompt: 'SEAT_STANCE_MARKER do not use tools',
+    });
+
+    expect(result.exitCode).toBe(0);
+    expect(result.stdout).toContain('--system-prompt');
+    expect(result.stdout).toContain('SEAT_STANCE_MARKER');
+  });
+
+  it('appends textOnlyArgs only when the dispatch sets textOnly', async () => {
+    const script = "process.stdout.write(JSON.stringify({ type: 'result', result: process.argv.slice(1).join(' ') }) + '\\n'); setInterval(() => {}, 1000);";
+    const config = {
+      protocol: 'stream-json' as const,
+      serverCmd: ['-e', script, '--'],
+      textOnlyArgs: ['--tools', ''],
+    };
+    const base = { binaryPath: process.execPath, config, prompt: 'hello', cwd: process.cwd(), timeout: 5, mode: 'exec' as const };
+
+    const withTextOnly = await companionDispatch({ ...base, textOnly: true });
+    expect(withTextOnly.stdout).toContain('--tools');
+
+    const withoutTextOnly = await companionDispatch({ ...base });
+    expect(withoutTextOnly.stdout).not.toContain('--tools');
+  });
+
+  it('returns empty stdout when a stream-json exec turn ends on tool_use, so the adapter falls through to CLI spawn', async () => {
+    const script = [
+      "process.stdout.write(JSON.stringify({ type: 'assistant', message: { content: [{ type: 'text', text: 'I will quickly verify the file paths.' }, { type: 'tool_use', name: 'Read', input: {} }] } }) + '\\n');",
+      "process.stdout.write(JSON.stringify({ type: 'result', result: 'I will quickly verify the file paths.' }) + '\\n');",
+      'setInterval(() => {}, 1000);',
+    ].join('');
+
+    const result = await companionDispatch({
+      binaryPath: process.execPath,
+      config: {
+        protocol: 'stream-json',
+        serverCmd: ['-e', script],
+      },
+      prompt: 'hello',
+      cwd: process.cwd(),
+      timeout: 5,
+      mode: 'exec',
+    });
+
+    expect(result.exitCode).toBe(0);
+    expect(result.stdout).toBe('');
+    expect(result.stderr).toContain('tool_use');
+    expect(result.stderr).toContain('quickly verify');
+  });
+
+  it('applies the tool_use backstop to review mode too (review turns inherently want tools)', async () => {
+    const script = [
+      "process.stdout.write(JSON.stringify({ type: 'assistant', message: { content: [{ type: 'text', text: 'Let me examine the diff first.' }, { type: 'tool_use', name: 'Bash', input: {} }] } }) + '\\n');",
+      "process.stdout.write(JSON.stringify({ type: 'result', result: 'Let me examine the diff first.' }) + '\\n');",
+      'setInterval(() => {}, 1000);',
+    ].join('');
+
+    const result = await companionDispatch({
+      binaryPath: process.execPath,
+      config: {
+        protocol: 'stream-json',
+        serverCmd: ['-e', script],
+      },
+      prompt: 'review this',
+      cwd: process.cwd(),
+      timeout: 5,
+      mode: 'review',
+    });
+
+    expect(result.exitCode).toBe(0);
+    expect(result.stdout).toBe('');
+    expect(result.stderr).toContain('tool_use');
+  });
+
   it('concatenates token-level ACP agent_message_chunk deltas instead of one word per paragraph', async () => {
     // Fake ACP server: answers initialize/session/new, then streams the agent
     // message as per-word chunks (kimi style) with a tool_call in the middle,
diff --git a/tests/unit/strip-stream-json.test.ts b/tests/unit/strip-stream-json.test.ts
new file mode 100644
index 000000000..7d675dda3
--- /dev/null
+++ b/tests/unit/strip-stream-json.test.ts
@@ -0,0 +1,67 @@
+import { describe, expect, it } from 'vitest';
+
+import { stripStreamJson } from '../../packages/adapter-cli/src/generated/adapter-helpers.js';
+
+function ndjson(...events: unknown[]): string {
+  return events.map((e) => JSON.stringify(e)).join('\n');
+}
+
+const assistantText = (text: string) => ({ type: 'assistant', message: { content: [{ type: 'text', text }] } });
+
+describe('stripStreamJson', () => {
+  it('prefers the final result event so the answer is not duplicated', () => {
+    const out = stripStreamJson(ndjson(
+      assistantText('## Answer\nfull answer body'),
+      { type: 'result', result: '## Answer\nfull answer body', is_error: false },
+    ));
+    expect(out).toBe('## Answer\nfull answer body');
+  });
+
+  it('drops tool preambles when a later result carries the real answer (multi-turn tool run)', () => {
+    const out = stripStreamJson(ndjson(
+      assistantText("I'll quickly verify the file paths."),
+      { type: 'assistant', message: { content: [{ type: 'tool_use', name: 'Read', input: {} }] } },
+      assistantText('The verified answer.'),
+      { type: 'result', result: 'The verified answer.', is_error: false },
+    ));
+    expect(out).toBe('The verified answer.');
+  });
+
+  it('falls back to assistant texts when the stream has no result event (timeout kill)', () => {
+    const out = stripStreamJson(ndjson(
+      assistantText('partial answer up to the cutoff'),
+    ));
+    expect(out).toBe('partial answer up to the cutoff');
+  });
+
+  it('falls back to assistant texts when the result event is an error (max-tokens truncation)', () => {
+    const out = stripStreamJson(ndjson(
+      assistantText('truncated but valid text'),
+      { type: 'result', result: '', is_error: true },
+    ));
+    expect(out).toBe('truncated but valid text');
+  });
+
+  it('never lets a non-string result payload mask the assistant text', () => {
+    const out = stripStreamJson(ndjson(
+      assistantText('the actual answer'),
+      { type: 'result', result: { some: 'object' }, is_error: false },
+    ));
+    expect(out).toContain('the actual answer');
+    expect(out).not.toBe('{"some":"object"}');
+  });
+
+  it('keeps raw non-JSON lines as-is', () => {
+    expect(stripStreamJson('plain engine output\nsecond line')).toBe('plain engine output\nsecond line');
+  });
+
+  it('skips system and hook events', () => {
+    const out = stripStreamJson(ndjson(
+      { type: 'system', subtype: 'init' },
+      { type: 'system', subtype: 'hook_started' },
+      assistantText('answer'),
+      { type: 'result', result: 'answer', is_error: false },
+    ));
+    expect(out).toBe('answer');
+  });
+});