feat(ui): boot context pill at session start by dimakis · Pull Request #313 · dimakis/mitzo

dimakis · 2026-05-04T22:23:25Z

Summary

Threads ContexGin compile() result from server through WebSocket protocol to a tappable pill at the top of the chat view
Shows source count, token count, and compilation engine (green dot for ContexGin, amber for local fallback)
Tappable to expand: lists source files and trimmed section count
Uses dynamic import('contexgin') to avoid bloating module load for tests

Files changed: server/chat.ts, packages/client/src/slices/messages.ts, packages/client/src/protocol-parser.ts, packages/client/src/index.ts, frontend/src/components/BootContextPill.tsx, frontend/src/components/ChatArea.tsx, frontend/src/pages/ChatView.tsx, frontend/src/styles/global.css

Test plan

Start Mitzo dev server with ContexGin running — pill shows green dot, accurate counts
Stop ContexGin, start new session — pill shows amber dot, "Fallback"
Tap pill — expands to show source file list
Resumed sessions — pill should not appear (correct, no re-compilation)
npx vitest run server/__tests__/chat.test.ts passes (30/30)
npx tsc --noEmit clean for modified files

🤖 Generated with Claude Code

dimakis

Centaur Review

Found 7 issue(s) (5 warning).

`frontend/src/pages/DesktopChatView.tsx`

Functional feature with clean UI integration, but DesktopChatView is missing the new prop (boot context won't render on desktop), the contexgin dependency is undeclared, error handling is overly broad, and the existing test suites were not updated.

🟡 regressions: DesktopChatView does not extract or pass bootContext (or sessionContext) to ChatArea. The mobile ChatView passes both props, but the desktop view omits them — boot context metadata will never render on desktop. [fixable]

`server/chat.ts`

Functional feature with clean UI integration, but DesktopChatView is missing the new prop (boot context won't render on desktop), the contexgin dependency is undeclared, error handling is overly broad, and the existing test suites were not updated.

🟡 unsafe_assumptions (L726): contexgin is dynamically imported but is not listed in any package.json dependencies. If the package is not installed, every session start will hit the .catch() path and emit a misleading local-fallback with all-zero counts, silently masking a missing dependency rather than signaling a configuration problem. [fixable]
🟡 unsafe_assumptions (L728): The compiled object's shape is assumed without validation — compiled.sources, compiled.bootTokens, and compiled.trimmed are accessed directly. If the contexgin API changes or returns an unexpected shape, undefined values will be sent over the wire and silently coerced by the client parser's as casts. [fixable]
🔵 bugs (L738): The .catch() handler swallows all errors (including runtime errors in the .then() callback like compiled.sources.map failing on a non-array) and emits a local-fallback event. Consider narrowing the catch to only handle the dynamic import failure, or at minimum logging the error so real bugs in the success path aren't silently eaten. [fixable]

`packages/client/src/protocol-parser.ts`

Functional feature with clean UI integration, but DesktopChatView is missing the new prop (boot context won't render on desktop), the contexgin dependency is undeclared, error handling is overly broad, and the existing test suites were not updated.

🟡 unsafe_assumptions (L197): All fields are coerced via as type assertions (msg.source as 'contexgin' | 'local-fallback', msg.sourceCount as number, etc.) with no runtime validation. If any field is missing or has the wrong type, the assertion passes silently and the UI gets undefined/NaN values. Other message types in this file use the same pattern, but new code should ideally validate shape. [fixable]

`packages/client/src/slices/messages.ts`

Functional feature with clean UI integration, but DesktopChatView is missing the new prop (boot context won't render on desktop), the contexgin dependency is undeclared, error handling is overly broad, and the existing test suites were not updated.

🟡 missing_tests (L390): Existing test files packages/client/__tests__/messages-slice.test.ts and packages/client/__tests__/protocol-parser.test.ts cover the messages reducer and protocol parser respectively, but neither has been updated with tests for the new SET_BOOT_CONTEXT action or the boot_context parser case. [fixable]

`frontend/src/components/BootContextPill.tsx`

Functional feature with clean UI integration, but DesktopChatView is missing the new prop (boot context won't render on desktop), the contexgin dependency is undeclared, error handling is overly broad, and the existing test suites were not updated.

🔵 style (L12): Hardcoded color strings '#4ade80' and '#fbbf24' bypass the project's CSS variable system (the rest of the codebase uses var(--*) tokens). The trimmed-count yellow in global.css (line 2362) also hardcodes #fbbf24. Consider using CSS variables for consistency and dark/light theme support. [fixable]

dimakis · 2026-05-04T22:25:55Z


-  // Fire-and-forget: capture prompt comparison for the experiments spoke
+  // Fire-and-forget: emit boot context metadata to client + capture prompt comparison
+  import('contexgin')


🟡 unsafe_assumptions: contexgin is dynamically imported but is not listed in any package.json dependencies. If the package is not installed, every session start will hit the .catch() path and emit a misleading local-fallback with all-zero counts, silently masking a missing dependency rather than signaling a configuration problem. [fixable]

dimakis · 2026-05-04T22:25:55Z

+  // Fire-and-forget: emit boot context metadata to client + capture prompt comparison
+  import('contexgin')
+    .then(({ compile }) => compile({ workspaceRoot: cwd, tokenBudget: 8000 }))
+    .then((compiled) => {


🟡 unsafe_assumptions: The compiled object's shape is assumed without validation — compiled.sources, compiled.bootTokens, and compiled.trimmed are accessed directly. If the contexgin API changes or returns an unexpected shape, undefined values will be sent over the wire and silently coerced by the client parser's as casts. [fixable]

dimakis · 2026-05-04T22:25:55Z

+        sources: compiled.sources.map((s: { relativePath: string }) => s.relativePath),
+      });
+    })
+    .catch(() => {


🔵 bugs: The .catch() handler swallows all errors (including runtime errors in the .then() callback like compiled.sources.map failing on a non-array) and emits a local-fallback event. Consider narrowing the catch to only handle the dynamic import failure, or at minimum logging the error so real bugs in the success path aren't silently eaten. [fixable]

dimakis · 2026-05-04T22:25:55Z

      });
      break;

+    case 'boot_context':


🟡 unsafe_assumptions: All fields are coerced via as type assertions (msg.source as 'contexgin' | 'local-fallback', msg.sourceCount as number, etc.) with no runtime validation. If any field is missing or has the wrong type, the assertion passes silently and the UI gets undefined/NaN values. Other message types in this file use the same pattern, but new code should ideally validate shape. [fixable]

dimakis · 2026-05-04T22:25:55Z

    case 'SET_SESSION_CONTEXT':
      return { ...state, sessionContext: action.context };

+    case 'SET_BOOT_CONTEXT':


🟡 missing_tests: Existing test files packages/client/__tests__/messages-slice.test.ts and packages/client/__tests__/protocol-parser.test.ts cover the messages reducer and protocol parser respectively, but neither has been updated with tests for the new SET_BOOT_CONTEXT action or the boot_context parser case. [fixable]

dimakis · 2026-05-04T22:25:55Z

+  const [expanded, setExpanded] = useState(false);
+
+  const isContexgin = context.source === 'contexgin';
+  const dotColor = isContexgin ? '#4ade80' : '#fbbf24';


🔵 style: Hardcoded color strings '#4ade80' and '#fbbf24' bypass the project's CSS variable system (the rest of the codebase uses var(--*) tokens). The trimmed-count yellow in global.css (line 2362) also hardcodes #fbbf24. Consider using CSS variables for consistency and dark/light theme support. [fixable]

…tests - Wire bootContext + sessionContext to DesktopChatView (was missing) - Server: async/await with try/catch, validate compiled shape, log errors - Protocol parser: runtime validation instead of bare `as` casts - CSS: define --status-ok/--status-warn vars, use class modifiers - Add 6 tests: SET_BOOT_CONTEXT reducer (3) + boot_context parser (3) Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

dimakis