Provenance: Spec 0016 — Chat API Error Handling and UI Error Display

Spec: .sdd/specification/spec-0016-chat-error-handling.md Executed: 2026-03-20 Agent: Claude Code CLI (claude-opus-4-6)

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Builder Agent Record

Actions Taken

1. Read .sdd/specification/spec-0016-chat-error-handling.md — full spec
2. Read sites/hq-kevinryan-io/app/api/chat/route.ts — server-side chat API route
3. Read sites/hq-kevinryan-io/app/components/ChatInterface.tsx — client-side chat UI
4. Read sites/hq-kevinryan-io/app/components/MessageBubble.tsx — message bubble rendering (no changes needed per spec)
5. Read sites/hq-kevinryan-io/app/types/chat.ts — TypeScript types (no changes needed)
6. Read .sdd/provenance/template.md — provenance template
7. Modified sites/hq-kevinryan-io/app/api/chat/route.ts — wrapped pre-stream code (session check returns JSON 401, request.json() in try/catch returns JSON 400)
8. Modified sites/hq-kevinryan-io/app/api/chat/route.ts — wrapped ReadableStream.start() body in try/catch with [HQ_ERROR] sentinel, moved controller.close() to finally block
9. Modified sites/hq-kevinryan-io/app/components/ChatInterface.tsx — replaced generic error handler with content-type-aware error extraction for non-200 responses
10. Modified sites/hq-kevinryan-io/app/components/ChatInterface.tsx — added [HQ_ERROR] sentinel detection after streaming while loop, before redacted-mode JSON parsing
11. Modified sites/hq-kevinryan-io/app/components/ChatInterface.tsx — added catch block for network-level errors around the fetch+streaming block
12. Ran pnpm install — installed all workspace dependencies
13. Ran pnpm --filter hq-kevinryan-io lint — passed (0 errors, 1 pre-existing warning)
14. Ran pnpm build — all sites compiled successfully
15. Created .sdd/provenance/spec-0016-chat-error-handling.provenance.md — this file

Decisions Made

No autonomous decisions were required — all actions were explicitly specified in the spec.

Assumptions

#	Assumption	Spec Reference	Rationale
A1	The existing try { ... } finally { setLoading(false) } in sendMessage serves as the outer try block for the catch added in section 2.3	Section 2.3 (“the existing code already has a finally { setLoading(false) }”)	The spec explicitly notes this structure should be preserved, not duplicated. The catch was added between the existing try body and the finally block.
A2	The [HQ_ERROR] sentinel detection runs unconditionally (both redacted and non-redacted modes)	Section 2.2 (“It should run in both normal and redacted mode”)	Spec explicitly states this. Placed the detection block before the if (redacted) conditional.

Ambiguities

#	Ambiguity	Spec Reference	Interpretation	Alternative Reading
B1	Whether the errorJson.error extraction should use a type assertion or remain loosely typed	Section 2.1 code snippet	Used implicit any from res.json() return type with optional chaining (errorJson.error ?? errorDetail) — this is safe because we’re in a try/catch and the value is coerced to string by template literal	Could add an explicit interface for the error response shape

Deviations from Spec

No deviations from spec.

Artifacts Produced

File	Status
.sdd/specification/spec-0016-chat-error-handling.md	Unchanged (pre-existing)
sites/hq-kevinryan-io/app/api/chat/route.ts	Modified
sites/hq-kevinryan-io/app/components/ChatInterface.tsx	Modified
.sdd/provenance/spec-0016-chat-error-handling.provenance.md	Created

Build Status

Status: Complete Summary: Implemented comprehensive error handling for the HQ chat interface: server-side try/catch around pre-stream code (JSON 401/400 responses), try/catch inside ReadableStream.start() with [HQ_ERROR] sentinel for mid-stream errors, client-side content-type-aware error extraction for non-200 responses, [HQ_ERROR] sentinel detection in streamed content, and network-level error catch around fetch. Known limitations: None — all spec requirements implemented as specified.

Validation Results

#	Check	Result
1	route.ts has try/catch around request.json() and returns JSON error responses for 401 and 400	Pass
2	route.ts has try/catch inside ReadableStream.start() with [HQ_ERROR] sentinel output	Pass
3	route.ts has controller.close() in a finally block	Pass
4	ChatInterface.tsx extracts status code, status text, and body from non-200 responses	Pass
5	ChatInterface.tsx detects [HQ_ERROR] sentinel in streamed content and rewrites the message	Pass
6	ChatInterface.tsx has a catch block around the fetch for network errors	Pass
7	pnpm lint passes (hq site: 0 errors)	Pass
8	pnpm build passes	Pass
9	Provenance record exists at .sdd/provenance/spec-0016-chat-error-handling.provenance.md	Pass
10	All files committed together	Pending (next step)

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Testing Agent Record

Not applicable for this spec — manual verification only per spec section “Testing Agent”.