fix(ai-client): prevent infinite tool call loop when finishReason is stop

[AlemTuzlak]

Summary

• When the server-side agent loop executes a tool and the model finishes with finishReason: 'stop', the client no longer auto-sends another request
• Previously, the continuation logic only checked if the last message part was tool-result and all tools were complete — it didn't check finishReason
• This caused infinite loops with non-OpenAI providers (Anthropic, OpenRouter, Gemini, etc.) that respond minimally after tool execution

Root cause

The ChatClient.streamResponse() continuation logic at the end of a successful stream:

if (lastPart?.type === 'tool-result' && this.shouldAutoSend()) {
  await this.checkForContinuation()
}

When a server tool executes and the model responds with finishReason: 'stop', the last part in the message is tool-result (from TOOL_CALL_END.result). areAllToolsComplete() returns true. The client auto-sends, the model calls the tool again, and the cycle repeats.

Fix

Check finishReason before auto-sending:

if (lastPart?.type === 'tool-result' && finishReason !== 'stop' && this.shouldAutoSend()) {

When the model says stop, it's done — no continuation needed.

Test plan

• pnpm --filter @tanstack/ai-client run test:lib — 198 tests pass
• Manual test: "recommend a guitar to me" with Anthropic and OpenRouter no longer loops
• OpenAI tool calls still work correctly (model calls recommendGuitar client tool)

Generated with Claude Code

Summary by CodeRabbit

Bug Fixes

• Fixed an infinite loop issue when using tools with non-OpenAI AI providers. The client now properly respects when a model signals completion and avoids unnecessary retries.

[github-actions]

🚀 Changeset Version Preview

1 package(s) bumped directly, 10 bumped as dependents.

🟩 Patch bumps

Package	Version	Reason
@tanstack/ai-client	0.7.5 → 0.7.6	Changeset
@tanstack/ai-preact	0.6.10 → 0.6.11	Dependent
@tanstack/ai-react	0.7.6 → 0.7.7	Dependent
@tanstack/ai-solid	0.6.10 → 0.6.11	Dependent
@tanstack/ai-svelte	0.6.10 → 0.6.11	Dependent
@tanstack/ai-vue	0.6.10 → 0.6.11	Dependent
@tanstack/ai-vue-ui	0.1.21 → 0.1.22	Dependent
@tanstack/smoke-tests-e2e	0.0.31 → 0.0.32	Dependent
ts-svelte-chat	0.1.25 → 0.1.26	Dependent
ts-vue-chat	0.1.25 → 0.1.26	Dependent
vanilla-chat	0.0.25 → 0.0.26	Dependent

[nx-cloud]

View your CI Pipeline Execution ↗ for commit 1b5c400

Command	Status	Duration	Result
nx affected --targets=test:sherif,test:knip,tes...	✅ Succeeded	1m 47s	View ↗
nx run-many --targets=build --exclude=examples/**	✅ Succeeded	2s	View ↗

---

☁️ Nx Cloud last updated this comment at 2026-04-01 17:04:24 UTC

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 653915a5-e6d1-49d0-a84a-c74404e188d1

📥 Commits

Reviewing files that changed from the base of the PR and between cc77237 and 1b5c400.

📒 Files selected for processing (2)

• .changeset/fix-infinite-tool-loop.md
• packages/typescript/ai-client/src/chat-client.ts

---

📝 Walkthrough

Walkthrough

A patch release for @tanstack/ai-client introduces a fix to prevent infinite tool call loops by preventing automatic resend of conversation flow when the model returns finishReason: 'stop' after tool execution.

Changes

Cohort / File(s)	Summary
Documentation .changeset/fix-infinite-tool-loop.md	New changeset entry documenting the patch release and behavior change for infinite tool loop prevention.
Core Client Logic packages/typescript/ai-client/src/chat-client.ts	Modified streamResponse() post-stream teardown logic to gate auto-resend continuation on finishReason !== 'stop', preventing re-sending when stream completes with stop reason.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Poem

🐰 A loop that spun round and round,
Now gently halts when 'stop' is found,
The finish line brings peace at last,
No more infinite loops so vast! ✨

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main fix: preventing infinite tool call loops when finishReason is 'stop'.
Description check	✅ Passed	The description includes detailed explanation of the issue, root cause, fix, and test plan. However, it lacks the checklist items from the required template.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/infinite-tool-loop

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[pkg-pr-new]

Open in StackBlitz

@tanstack/ai

npm i https://pkg.pr.new/@tanstack/ai@412

@tanstack/ai-anthropic

npm i https://pkg.pr.new/@tanstack/ai-anthropic@412

@tanstack/ai-client

npm i https://pkg.pr.new/@tanstack/ai-client@412

@tanstack/ai-devtools-core

npm i https://pkg.pr.new/@tanstack/ai-devtools-core@412

@tanstack/ai-elevenlabs

npm i https://pkg.pr.new/@tanstack/ai-elevenlabs@412

@tanstack/ai-event-client

npm i https://pkg.pr.new/@tanstack/ai-event-client@412

@tanstack/ai-fal

npm i https://pkg.pr.new/@tanstack/ai-fal@412

@tanstack/ai-gemini

npm i https://pkg.pr.new/@tanstack/ai-gemini@412

@tanstack/ai-grok

npm i https://pkg.pr.new/@tanstack/ai-grok@412

@tanstack/ai-groq

npm i https://pkg.pr.new/@tanstack/ai-groq@412

@tanstack/ai-ollama

npm i https://pkg.pr.new/@tanstack/ai-ollama@412

@tanstack/ai-openai

npm i https://pkg.pr.new/@tanstack/ai-openai@412

@tanstack/ai-openrouter

npm i https://pkg.pr.new/@tanstack/ai-openrouter@412

@tanstack/ai-preact

npm i https://pkg.pr.new/@tanstack/ai-preact@412

@tanstack/ai-react

npm i https://pkg.pr.new/@tanstack/ai-react@412

@tanstack/ai-react-ui

npm i https://pkg.pr.new/@tanstack/ai-react-ui@412

@tanstack/ai-solid

npm i https://pkg.pr.new/@tanstack/ai-solid@412

@tanstack/ai-solid-ui

npm i https://pkg.pr.new/@tanstack/ai-solid-ui@412

@tanstack/ai-svelte

npm i https://pkg.pr.new/@tanstack/ai-svelte@412

@tanstack/ai-vue

npm i https://pkg.pr.new/@tanstack/ai-vue@412

@tanstack/ai-vue-ui

npm i https://pkg.pr.new/@tanstack/ai-vue-ui@412

@tanstack/preact-ai-devtools

npm i https://pkg.pr.new/@tanstack/preact-ai-devtools@412

@tanstack/react-ai-devtools

npm i https://pkg.pr.new/@tanstack/react-ai-devtools@412

@tanstack/solid-ai-devtools

npm i https://pkg.pr.new/@tanstack/solid-ai-devtools@412

commit: 1b5c400