feat(tasks): add workspace code diff mode

package.json

@@ -40,6 +40,7 @@
     "@electric-sql/client": "^1.5.4",
     "@octokit/webhooks": "^14.2.0",
     "@opencode-ai/sdk": "^1.2.1",
+    "@pierre/diffs": "^1.0.11",
     "@tailwindcss/vite": "^4.1.18",
     "@tanstack/electric-db-collection": "^0.2.33",
     "@tanstack/hotkeys": "^0.4.1",

packages/desktop-shell/src/desktop-runner.mts

@@ -37,6 +37,14 @@ type RunnerModelProvider = {
   name: string;
 };
 
+type RunnerDiff = {
+  additions: number;
+  after: string;
+  before: string;
+  deletions: number;
+  file: string;
+};
+
 type ListRunnerModelsResponse = {
   connected: string[];
   default: Record<string, string>;
@@ -75,6 +83,7 @@ type AppRunnerController = {
     workspaceDirectory: string;
   }>;
   deleteRunnerWorkspace: (args: DeleteRunnerWorkspaceArgs) => Promise<void>;
+  getRunnerDiff: (args: { directory: string; sessionId: string }) => Promise<RunnerDiff[]>;
   listRunnerModels: (args: { directory: string }) => Promise<ListRunnerModelsResponse>;
   openWorkspaceInEditor: (args: OpenWorkspaceInEditorArgs) => Promise<void>;
   promptRunnerTask: (args: PromptRunnerTaskArgs) => Promise<void>;
@@ -94,6 +103,10 @@ type DeleteWorkspaceResponse = {
   ok: boolean;
 };
 
+type GetRunnerDiffResponse = {
+  diffs: RunnerDiff[];
+};
+
 export function createDesktopRunnerController({
   workspaceRoot,
 }: {
@@ -138,6 +151,13 @@ export function createDesktopRunnerController({
     );
   }
 
+  async function getRunnerDiff(args: {
+    directory: string;
+    sessionId: string;
+  }): Promise<RunnerDiff[]> {
+    return await requestRunnerDiff(args);
+  }
+
   async function promptRunnerTask(args: PromptRunnerTaskArgs): Promise<void> {
     const runner = await ensureRunner();
     const payload = await postRunnerJson<PromptTaskAssistantSessionResponse>(
@@ -264,9 +284,25 @@ export function createDesktopRunnerController({
     return nextRunnerProcess;
   }
 
+  async function requestRunnerDiff(args: {
+    directory: string;
+    sessionId: string;
+  }): Promise<RunnerDiff[]> {
+    const runner = await ensureRunner();
+    const payload = await getRunnerJson<GetRunnerDiffResponse>(
+      `${runner.baseUrl}/assistant/session/diff?${new URLSearchParams({
+        directory: args.directory,
+        sessionId: args.sessionId,
+      }).toString()}`,
+    );
+
+    return payload.diffs;
+  }
+
   return {
     createRunnerSession,
     deleteRunnerWorkspace,
+    getRunnerDiff,
     listRunnerModels,
     openWorkspaceInEditor,
     promptRunnerTask,

packages/desktop-shell/src/index.mts

@@ -49,6 +49,10 @@ function registerIpcHandlers(): void {
     return await getDesktopRunnerController().deleteRunnerWorkspace(args);
   });
 
+  ipcMain.handle("desktop-runner:get-diff", async (_event, args) => {
+    return await getDesktopRunnerController().getRunnerDiff(args);
+  });
+
   ipcMain.handle("desktop-runner:list-models", async (_event, args) => {
     return await getDesktopRunnerController().listRunnerModels(args);
   });

packages/desktop-shell/src/preload.mts

@@ -7,6 +7,9 @@ contextBridge.exposeInMainWorld("clankiDesktop", {
   deleteRunnerWorkspace(workspaceDirectory: string) {
     return ipcRenderer.invoke("desktop-runner:delete-workspace", { workspaceDirectory });
   },
+  getRunnerDiff(args: { directory: string; sessionId: string }) {
+    return ipcRenderer.invoke("desktop-runner:get-diff", args);
+  },
   listRunnerModels(args: { directory: string }) {
     return ipcRenderer.invoke("desktop-runner:list-models", args);
   },

packages/runner/src/assistant-session-diff.ts

@@ -0,0 +1,143 @@
+import fs from "node:fs";
+import path from "node:path";
+import { spawnSync } from "node:child_process";
+import type { FileDiff } from "@opencode-ai/sdk";
+
+export async function getAssistantSessionDiff(args: {
+  directory: string;
+  messageId?: string;
+  sessionId: string;
+}): Promise<FileDiff[]> {
+  void args.messageId;
+  void args.sessionId;
+
+  const directory = path.resolve(args.directory);
+  const defaultBranch = resolveDefaultBranch(directory);
+  fetchDefaultBranch(directory, defaultBranch);
+
+  const mergeBase = runGitCommand(
+    directory,
+    ["merge-base", `origin/${defaultBranch}`, "HEAD"],
+    "Failed to resolve merge base for workspace diff",
+  ).trim();
+
+  if (mergeBase.length === 0) {
+    throw new Error("Failed to resolve merge base for workspace diff");
+  }
+
+  const changedFiles = listChangedFiles(directory, mergeBase);
+
+  return changedFiles.map((file) => {
+    const stats = readDiffStats(directory, mergeBase, file);
+
+    return {
+      additions: stats.additions,
+      after: readWorkingTreeFile(directory, file),
+      before: readGitFile(directory, mergeBase, file),
+      deletions: stats.deletions,
+      file,
+    };
+  });
+}
+
+function fetchDefaultBranch(directory: string, defaultBranch: string): void {
+  runGitCommand(
+    directory,
+    ["fetch", "origin", defaultBranch, "--prune"],
+    `Failed to fetch origin/${defaultBranch} for workspace diff`,
+  );
+}
+
+function listChangedFiles(directory: string, mergeBase: string): string[] {
+  const output = runGitCommand(
+    directory,
+    ["diff", "--name-only", "--no-renames", mergeBase, "--"],
+    "Failed to list workspace diff files",
+  );
+
+  return output
+    .split("\n")
+    .map((line) => line.trim())
+    .filter((line) => line.length > 0);
+}
+
+function readGitFile(directory: string, revision: string, file: string): string {
+  const output = spawnSync("git", ["-C", directory, "show", `${revision}:${file}`], {
+    encoding: "utf8",
+    stdio: ["ignore", "pipe", "pipe"],
+  });
+
+  if (output.status === 0) {
+    return output.stdout;
+  }
+
+  const stderr = output.stderr.trim();
+  if (stderr.includes("exists on disk, but not in") || stderr.includes("does not exist in")) {
+    return "";
+  }
+
+  throw new Error(stderr || `Failed to read ${file} from ${revision}`);
+}
+
+function readDiffStats(
+  directory: string,
+  mergeBase: string,
+  file: string,
+): { additions: number; deletions: number } {
+  const output = runGitCommand(
+    directory,
+    ["diff", "--numstat", "--no-renames", mergeBase, "--", file],
+    `Failed to read diff stats for ${file}`,
+  ).trim();
+
+  const [additionsRaw = "0", deletionsRaw = "0"] = output.split("\t");
+
+  return {
+    additions: Number.parseInt(additionsRaw, 10) || 0,
+    deletions: Number.parseInt(deletionsRaw, 10) || 0,
+  };
+}
+
+function readWorkingTreeFile(directory: string, file: string): string {
+  const absolutePath = path.join(directory, file);
+  if (!fs.existsSync(absolutePath)) {
+    return "";
+  }
+
+  return fs.readFileSync(absolutePath, "utf8");
+}
+
+function resolveDefaultBranch(directory: string): string {
+  const branch = runGitCommand(
+    directory,
+    ["symbolic-ref", "--short", "refs/remotes/origin/HEAD"],
+    "Failed to resolve default branch for workspace diff",
+  )
+    .trim()
+    .replace(/^origin\//u, "");
+
+  if (branch.length === 0) {
+    throw new Error("Failed to resolve default branch for workspace diff");
+  }
+
+  return branch;
+}
+
+function runGitCommand(directory: string, args: string[], errorContext: string): string {
+  const output = spawnSync("git", ["-C", directory, ...args], {
+    encoding: "utf8",
+    stdio: ["ignore", "pipe", "pipe"],
+  });
+
+  if (output.error) {
+    throw new Error(`${errorContext}: ${output.error.message}`);
+  }
+
+  if (output.status === 0) {
+    return output.stdout;
+  }
+
+  const stderr = output.stderr.trim();
+  const stdout = output.stdout.trim();
+  throw new Error(`${errorContext}: ${stderr || stdout || `exit status ${output.status}`}`);
+}

packages/runner/src/index.ts

@@ -1,4 +1,5 @@
 export * from "./assistant-session";
+export * from "./assistant-session-diff";
 export * from "./local-runner-client";
 export * from "./local-runner-protocol";
 export * from "./local-runner-server";

packages/runner/src/local-runner-client.ts

@@ -5,6 +5,8 @@ import type {
   DeleteWorkspaceResponse,
   EnsureAssistantSessionRequest,
   EnsureAssistantSessionResponse,
+  GetAssistantSessionDiffRequest,
+  GetAssistantSessionDiffResponse,
   ListAssistantSessionsRequest,
   ListAssistantSessionsResponse,
   ListOpencodeModelsRequest,
@@ -32,6 +34,22 @@ export function createLocalRunnerClient(baseUrl: string) {
     ): Promise<EnsureAssistantSessionResponse> {
       return await postJson(`${normalizedBaseUrl}/assistant/session/ensure`, body);
     },
+    async getAssistantSessionDiff(
+      params: GetAssistantSessionDiffRequest,
+    ): Promise<GetAssistantSessionDiffResponse> {
+      const searchParams = new URLSearchParams({
+        directory: params.directory,
+        sessionId: params.sessionId,
+      });
+
+      if (params.messageId) {
+        searchParams.set("messageId", params.messageId);
+      }
+
+      return await getJson(
+        `${normalizedBaseUrl}/assistant/session/diff?${searchParams.toString()}`,
+      );
+    },
     async health(): Promise<LocalRunnerHealthResponse> {
       return await getJson(`${normalizedBaseUrl}/health`);
     },

packages/runner/src/local-runner-protocol.ts

@@ -1,4 +1,4 @@
-import type { ProviderListResponse } from "@opencode-ai/sdk";
+import type { FileDiff, ProviderListResponse } from "@opencode-ai/sdk";
 
 export const LOCAL_RUNNER_PROTOCOL_VERSION = "v1alpha1";
 
@@ -67,6 +67,16 @@ export type ListAssistantSessionsResponse = {
   sessions: AssistantSessionSummary[];
 };
 
+export type GetAssistantSessionDiffRequest = {
+  directory: string;
+  messageId?: string;
+  sessionId: string;
+};
+
+export type GetAssistantSessionDiffResponse = {
+  diffs: FileDiff[];
+};
+
 export type PromptAssistantSessionRequest = {
   directory: string;
   model?: string;