FE-534: Walking skeleton SDK to SSE to React by lunelson · Pull Request #10 · hashintel/brunch

lunelson · 2026-03-30T16:25:31Z

Add memory/SPEC.md with full v2 product spec
Add memory/ROADMAP.md with 12 sliced issues (FE-534–FE-545)
Update AGENTS.md with git/linear/graphite conventions
Move REFACTORS.md, REMODEL.md to docs/design/
Move TEST_PROBLEMS.md to docs/test-scenarios/

- Add memory/SPEC.md with full v2 product spec - Add memory/ROADMAP.md with 12 sliced issues (FE-534–FE-545) - Update AGENTS.md with git/linear/graphite conventions - Move REFACTORS.md, REMODEL.md to docs/design/ - Move TEST_PROBLEMS.md to docs/test-scenarios/

linear · 2026-03-30T16:25:36Z

FE-534 Walking skeleton: SDK → SSE → React

Prove the integration seam end-to-end. New Express route, pipeSDKStream adapter (Design A), React + Vite + useChat. Thinking, text, tool-use events visible in browser. No DB, no domain logic.

lunelson · 2026-03-30T16:25:44Z

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…ation - Define canonical section schemas for SPEC.md (concept, constraints, requirements, assumptions, decisions, lexicon, verification design, acceptance criteria) and PLAN.md (phases with slices/spikes, cross-referencing SPEC.md) - Extract templates to resources/ subdirs (ln-spec, ln-plan), matching ln-handoff pattern - Add traceability hygiene to ln-spec, ln-plan, ln-build, ln-spike, ln-scope - Expand routing tables across all execution skills to include ln-spec/ln-plan escalation - Add lexicon alignment survey to ln-review (feeds into ln-refactor) - Add routing table to ln-sync - Make ln-spec and ln-plan re-runnable (read-first, update semantics) - Migrate memory/SPEC.md to new schema: surface 10 implicit assumptions, build 19-term lexicon, consolidate acceptance criteria, fold Q&A into decision rationale - Rename memory/ROADMAP.md → PLAN.md: organize 12 slices into 4 phases + horizon, add requirement/assumption cross-references to every slice - Update templates bidirectionally: add issue IDs, branches, acceptance, dependencies sections from existing docs back into plan-template - Add HTML comments throughout templates and docs as section-level guidance - Update AGENTS.md with protocol docs (two-document system, skill flow, symlinks) - Add .claude/skills → .agents/skills symlink for Claude Code compatibility Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

- ln-grill: add anti-pattern naming and lexicon sharpening behaviors - ln-plan: add epistemic horizon and spike economics concepts - AGENTS.md: tie git/Linear/planning into one workflow (PLAN.md → Linear issue → Graphite stacked branch) - Delete docs/design/REFACTORS.md (absorbed into REMODEL.md and SPEC.md) - Add cli-graphite, cli-linear skill references Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Prove the integration seam: Claude Agent SDK query() streams through an Express SSE adapter emitting AI SDK UI Message Stream protocol events, consumed by @ai-sdk/react useChat hook rendering thinking and text in a React UI. - SSE adapter (pure function): translates SDK stream events to AI SDK protocol (text-start/delta/end, reasoning-start/delta/end, start, finish-step, finish, [DONE]) - Express POST /api/chat handler with SDK integration - React + Vite client with useChat, thinking/text rendering - 17 tests (10 unit, 5 integration, 2 format) - TypeScript throughout, strict mode - Replaced Preact with React, removed v1 deps (mysql2, dnd-kit, etc.) Validates assumptions A1, A2, A8, A10. Establishes invariants I1-I4 (SSE conformance, stream lifecycle, thinking/text separation, Vite proxy routing). Also: refine ln-* skills (scope-before-build routing, mandatory traceability, invariants as first-class ledger in spec template). Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

augmentcode

Review completed. 5 suggestions posted.

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augmentcode · 2026-04-01T11:34:13Z

+type SDKMessage = SDKStreamEvent | SDKOtherMessage;
+
+// Track content block types by index
+const thinkingBlocks = new Set<number>();


src/server/sse-adapter.ts:39-41 — thinkingBlocks/textBlocks are module-level mutable state, so concurrent /api/chat requests can interfere with each other. In particular, one request’s resetAdapter() can clear another request’s in-flight block tracking and cause incorrect *-end events or missing events.

Severity: high

_{🤖 Was this useful? React with 👍 or 👎, or 🚀 if it prevented an incident/outage.}

augmentcode · 2026-04-01T11:34:13Z

+
+	switch (event.type) {
+		case 'message_start':
+			return [{ type: 'start', messageId: event.message!.id }];


src/server/sse-adapter.ts:61-87 — Several non-null assertions (event.message!, event.content_block!, event.delta!, event.index!, delta.text!/delta.thinking!) will throw if the SDK ever emits an unexpected/partial shape. That would terminate the SSE stream and can also generate protocol ids like reasoning-undefined / text-undefined if index is absent.

Severity: medium

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augmentcode · 2026-04-01T11:34:13Z

+			},
+		});
+
+		for await (const sdkMessage of stream) {


src/server/app.ts:36-43 — If the client disconnects mid-stream, the for await loop will likely keep consuming from query() and attempting res.write(...) on a closed response. This can waste tokens/compute and may surface as noisy errors unless the stream is cancelled on req/res close.

Severity: medium

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augmentcode · 2026-04-01T11:34:13Z

+		?? lastMessage?.parts?.filter((p: { type: string }) => p.type === 'text')
+			.map((p: { text: string }) => p.text).join('') ?? '';
+
+	console.log('POST /api/chat — prompt:', JSON.stringify(prompt).substring(0, 100));


src/server/app.ts:17 — Logging the user prompt (even truncated) can unintentionally persist sensitive user input/PII into server logs. If this endpoint is used beyond local dev, it’s worth ensuring the logging policy matches your privacy/security requirements.

Severity: low

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augmentcode · 2026-04-01T11:34:13Z

+	});
+});
+
+describe('translateEvent', () => {


src/server/sse-adapter.test.ts:16 — translateEvent depends on module-level adapter state (thinkingBlocks/textBlocks), but these tests don’t reset that state between cases. This can make the suite order-dependent or flaky if tests are run concurrently or re-ordered.

Severity: medium

_{🤖 Was this useful? React with 👍 or 👎, or 🚀 if it prevented an incident/outage.}

lunelson · 2026-04-02T06:20:27Z

Merge activity

Apr 2, 6:20 AM UTC: A user started a stack merge that includes this pull request via Graphite.
Apr 2, 6:20 AM UTC: @lunelson merged this pull request with Graphite.

lunelson and others added 4 commits March 31, 2026 13:23

port in dev- skills as local ln- skills; refocus language and contracts

0f0571f

lunelson mentioned this pull request Mar 31, 2026

FE-535: SQLite foundation and project persistence #11

Merged

lunelson changed the title ~~chore: scaffold v2 planning docs and project structure~~ FE-534: Walking skeleton SDK to SSE to React Apr 1, 2026

lunelson marked this pull request as ready for review April 1, 2026 11:29

lunelson mentioned this pull request Apr 1, 2026

FE-544: Turn tree schema and API #13

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augmentcode Bot reviewed Apr 1, 2026

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This was referenced Apr 1, 2026

FE-552: Drizzle ORM and core extraction #14

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FE-553: Multi-project routing #16

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FE-541: Rich chat UI with tool calls and reasoning rendering #15

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lunelson self-assigned this Apr 1, 2026

lunelson mentioned this pull request Apr 1, 2026

FE-554: Structured interview: scope phase #17

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lunelson merged commit 2e1c910 into main Apr 2, 2026
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FE-534: Walking skeleton SDK to SSE to React#10

FE-534: Walking skeleton SDK to SSE to React#10
lunelson merged 5 commits into
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