fix(a2ui): move history storage from server to client by Sherry-hue · Pull Request #2675 · lynx-family/lynx-stack

Sherry-hue · 2026-05-20T03:45:54Z

Summary by CodeRabbit

New Features
- Client-provided conversation context is now accepted for chat and action requests, enabling bounded histories and model-backed data to flow with each request.
Bug Fixes
- Improved handling of malformed JSON escapes in model output and safer recovery when generation fails.
Documentation
- Deployment guidance updated to clarify serverless/multi-replica suitability and client-driven conversation responsibilities.
Chores
- Removed server-side per-thread conversation memory; conversation size and content are validated with configurable limits.

Checklist

Tests updated (or not required).
Documentation updated (or not required).
Changeset added, and when a BREAKING CHANGE occurs, it needs to be clearly marked (or not required).

changeset-bot · 2026-05-20T03:45:59Z

⚠️ No Changeset found

Latest commit: 772593c

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coderabbitai · 2026-05-20T03:46:18Z

📝 Walkthrough

Walkthrough

This PR moves conversation memory from server-side threadId-backed storage to a client-supplied ConversationContext, adds validation and size limits, updates service and route signatures to accept conversation context, and updates the playground client to build, send, and apply conversation/data-model payloads.

Changes

Conversation state migration from server-side threads to client context

Layer / File(s)	Summary
Service layer: conversation context contract and API updates `packages/genui/server/service/a2ui-agent.ts`	Introduces `ConversationContext` interface (history + dataModel), removes `ChatOptions.threadId`, and updates `streamAsAsyncIterable`, `generateRaw`, `generateValidated` to accept optional `conversation` parameter. Removes internal `ConversationMemory` structure, thread-lifecycle methods (`getConversation`, `peekConversation`, `resetConversation`, `recordStreamedConversation`), and thread-based conversation merging helpers. Adds `buildConversationMessages` helper to construct prompts from history and data model.
Shared request body validation: conversation shape and limits `packages/genui/server/app/a2ui/_shared.ts`	Introduces `ConversationContext` type import, adds `MAX_CONVERSATION_CHARS` constant, updates `A2UIChatBody` to accept `conversation` field instead of `threadId`, removes threadId from `pickChatOptions`, and implements `validateConversation` function that validates message roles/counts, character limits, and data model structure with 400/413 error responses.
Route handlers: validation and conversation forwarding `packages/genui/server/app/a2ui/chat/route.ts`, `packages/genui/server/app/a2ui/stream/route.ts`, `packages/genui/server/app/a2ui/action/route.ts`, `packages/genui/server/app/a2ui/action/stream/route.ts`	All four route handlers updated to validate `body.conversation` via `validateConversation`, return CORS-wrapped errors on validation failure, and pass validated conversation to service methods. Removes thread-based conversation lookups, `recordStreamedConversation` calls, `threadId` requirements, and reset behavior. Updated `A2UIActionBody` and `A2UIActionStreamBody` contracts.
Client: conversation context building and data model updates `packages/genui/a2ui-playground/src/pages/AIChatPage.tsx`	Adds conversation-context building utilities: `ConversationContext` interface, `MAX_CONVERSATION_TURNS`/`MAX_CONVERSATION_CHARS` bounds, `buildConversationContext()` function, data-model cloning/patching helpers, and `dataModelRef` state. Refactors send/action flows to snapshot conversation context, pass it in request bodies, apply returned `updateDataModel` mutations, and restore context on failure. Removes threadId tracking and SSE `start` event handling.
Documentation and parsing/prompt updates `packages/genui/server/AGENTS.md`, `packages/genui/server/agent/a2ui-agent.ts`, `packages/genui/server/agent/a2ui-prompt.ts`, `packages/genui/server/agent/a2ui-validator.ts`	Updates `AGENTS.md` deployment guidance to reflect serverless/multi-replica safety via client-supplied conversation context; removes TTL/LRU conversation-memory documentation. Removes `threadId` from run options. Rewrites `PROTOCOL_OVERVIEW` system prompt to reference client-held conversation instead of `threadId`. Adds JSON escape sanitization in `a2ui-validator.ts` to retry parsing of malformed JSON with minimal unescape logic.

Estimated code review effort

🎯 4 (Complex) | ⏱️ ~60 minutes

Possibly related PRs

lynx-family/lynx-stack#2667: Refactors action-streaming flows; related to removing threadId-based action streaming and switching to conversation payloads.
lynx-family/lynx-stack#2472: Earlier AIChatPage scaffold that this PR extends with ConversationContext and data-model handling.

Suggested reviewers

PupilTong
HuJean

Poem

🐰 I cloned the model, trimmed the past,
I sent the context—compact and fast,
No threads to hold what clients keep,
Conversations flow, and rabbits leap! 🥕

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title accurately summarizes the main architectural change: moving conversation history storage from server-side (threadId-based in-memory state) to client-side (ConversationContext sent per request), which is the primary objective across all modified files.

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codecov · 2026-05-20T03:48:19Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ All tests successful. No failed tests found.

📢 Thoughts on this report? Let us know!

coderabbitai

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@packages/genui/server/agent/a2ui-validator.ts`:
- Around line 180-182: The current code applies unescapeInvalidJsonEscapes
before the initial JSON.parse which can corrupt valid strings (e.g., "\\\\x");
change the flow so you first build the candidate body from
stripCodeFenceWrapper(text) and unescapeInvalidBackticks(...) and attempt
JSON.parse on that original candidate, and only if the parse fails apply
unescapeInvalidJsonEscapes to the candidate (or to the failing parse input) and
retry parsing; update usages of the body variable and any error handling to
reflect the two-step parse attempt and keep functions
unescapeInvalidJsonEscapes, stripCodeFenceWrapper, and unescapeInvalidBackticks
as referenced symbols.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

Push a commit to this branch (recommended)
Create a new PR with the fixes

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 4820960f-38fe-45f2-8601-425154452c7c

📥 Commits

Reviewing files that changed from the base of the PR and between bf08205 and cab3aaa.

📒 Files selected for processing (12)

packages/genui/a2ui-playground/src/pages/AIChatPage.tsx
packages/genui/server/AGENTS.md
packages/genui/server/agent/a2ui-agent.ts
packages/genui/server/agent/a2ui-prompt.ts
packages/genui/server/agent/a2ui-validator.ts
packages/genui/server/app/a2ui/_shared.ts
packages/genui/server/app/a2ui/action/route.ts
packages/genui/server/app/a2ui/action/stream/route.ts
packages/genui/server/app/a2ui/chat/route.ts
packages/genui/server/app/a2ui/reset/route.ts
packages/genui/server/app/a2ui/stream/route.ts
packages/genui/server/service/a2ui-agent.ts

💤 Files with no reviewable changes (2)

packages/genui/server/app/a2ui/reset/route.ts
packages/genui/server/agent/a2ui-agent.ts

coderabbitai

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@packages/genui/server/app/a2ui/action/route.ts`:
- Around line 55-60: The early-return validation for missing action.name in the
route handler currently returns a 200 response; update the conditional that
checks if (!body.action || !body.action.name) to return the same bad-request
status used by the conversation validation branch (i.e., set HTTP status 400)
when calling jsonWithCors so the response indicates a client validation error;
adjust the jsonWithCors call in that block (the one returning { ok: false,
error: 'action.name is required' }) to include the 400 status.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

Push a commit to this branch (recommended)
Create a new PR with the fixes

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 94866cfc-4f37-4fdd-b737-4cbb9c84006f

📥 Commits

Reviewing files that changed from the base of the PR and between cab3aaa and 772593c.

📒 Files selected for processing (12)

packages/genui/a2ui-playground/src/pages/AIChatPage.tsx
packages/genui/server/AGENTS.md
packages/genui/server/agent/a2ui-agent.ts
packages/genui/server/agent/a2ui-prompt.ts
packages/genui/server/agent/a2ui-validator.ts
packages/genui/server/app/a2ui/_shared.ts
packages/genui/server/app/a2ui/action/route.ts
packages/genui/server/app/a2ui/action/stream/route.ts
packages/genui/server/app/a2ui/chat/route.ts
packages/genui/server/app/a2ui/reset/route.ts
packages/genui/server/app/a2ui/stream/route.ts
packages/genui/server/service/a2ui-agent.ts

💤 Files with no reviewable changes (2)

packages/genui/server/app/a2ui/reset/route.ts
packages/genui/server/agent/a2ui-agent.ts

✅ Files skipped from review due to trivial changes (1)

packages/genui/server/agent/a2ui-prompt.ts

codspeed-hq · 2026-05-20T04:31:00Z

Merging this PR will degrade performance by 7.06%

⚠️

Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

❌ 1 regressed benchmark
✅ 80 untouched benchmarks
⏩ 26 skipped benchmarks¹

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Benchmark	`BASE`	`HEAD`	Efficiency
❌	`transform 1000 view elements`	40 ms	43 ms	-7.06%

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

_{Comparing Sherry-hue:fix/remove-server-history (772593c) with main (bf08205)}

26 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

relativeci · 2026-05-20T04:35:00Z

React Example

#8485 Bundle Size — 237.74KiB (0%).

772593c(current) vs bf08205 main#8482(baseline)

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Bundle size by type no changes

	Current #8485	Baseline #8482
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Bundle analysis report Branch Sherry-hue:fix/remove-server-his... Project dashboard

^{Generated by RelativeCI Documentation Report issue}

relativeci · 2026-05-20T04:35:04Z

React External

#1600 Bundle Size — 697.9KiB (0%).

772593c(current) vs bf08205 main#1597(baseline)

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Bundle analysis report Branch Sherry-hue:fix/remove-server-his... Project dashboard

^{Generated by RelativeCI Documentation Report issue}

relativeci · 2026-05-20T04:35:04Z

React MTF Example

#1618 Bundle Size — 208.69KiB (0%).

772593c(current) vs bf08205 main#1615(baseline)

Bundle metrics no changes

	Current #1618	Baseline #1615
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Bundle size by type no changes

	Current #1618	Baseline #1615
IMG	`111.23KiB`	`111.23KiB`
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Bundle analysis report Branch Sherry-hue:fix/remove-server-his... Project dashboard

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relativeci · 2026-05-20T04:35:07Z

React Example with Element Template

#754 Bundle Size — 204.53KiB (0%).

772593c(current) vs bf08205 main#751(baseline)

Bundle metrics

2 changes

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Bundle analysis report Branch Sherry-hue:fix/remove-server-his... Project dashboard

^{Generated by RelativeCI Documentation Report issue}

relativeci · 2026-05-20T04:35:07Z

Web Explorer

#10059 Bundle Size — 903.53KiB (0%).

772593c(current) vs bf08205 main#10056(baseline)

Bundle metrics

2 changes

	Current #10059	Baseline #10056
Initial JS	`45.06KiB`	`45.06KiB`
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Chunks	`9`	`9`
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Bundle size by type no changes

	Current #10059	Baseline #10056
JS	`499.15KiB`	`499.15KiB`
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Bundle analysis report Branch Sherry-hue:fix/remove-server-his... Project dashboard

^{Generated by RelativeCI Documentation Report issue}

coderabbitai Bot reviewed May 20, 2026

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Comment thread packages/genui/server/agent/a2ui-validator.ts Outdated

fix(web): move history storage from server to client

772593c

Sherry-hue force-pushed the fix/remove-server-history branch from cab3aaa to 772593c Compare May 20, 2026 04:05

coderabbitai Bot reviewed May 20, 2026

View reviewed changes

Comment thread packages/genui/server/app/a2ui/action/route.ts

Sherry-hue changed the title ~~fix(web): move history storage from server to client~~ fix(a2ui): move history storage from server to client May 20, 2026

gaoachao self-requested a review May 20, 2026 05:52

gaoachao approved these changes May 20, 2026

View reviewed changes

gaoachao merged commit 3901c96 into lynx-family:main May 20, 2026
54 of 55 checks passed

This was referenced May 20, 2026

feat(a2ui): add multi conversations #2676

Merged

feat(a2ui): add catalog example, json valid, stream repair #2686

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codspeed-hq Bot commented May 20, 2026

Merging this PR will degrade performance by 7.06%

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relativeci Bot commented May 20, 2026

React Example

#8485 Bundle Size — 237.74KiB (0%).

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relativeci Bot commented May 20, 2026

React External

#1600 Bundle Size — 697.9KiB (0%).

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relativeci Bot commented May 20, 2026

React MTF Example

#1618 Bundle Size — 208.69KiB (0%).

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relativeci Bot commented May 20, 2026

React Example with Element Template

#754 Bundle Size — 204.53KiB (0%).

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Web Explorer

#10059 Bundle Size — 903.53KiB (0%).

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