fix(packages/agents): prevent unhandled promise rejections in stream()

[zrosenbauer]

Summary

• Add no-op .catch(() => {}) handlers on all 4 derived promises (output, messages, usage, finishReason) in both agent.stream() and flowAgent.stream()
• When the underlying stream errors and consumers don't await all promises, this prevents Node.js UnhandledPromiseRejection warnings
• Add tests in both agent.test.ts and flow-agent.test.ts verifying no unhandledRejection event fires

Test plan

• pnpm test --filter=@funkai/agents passes
• New tests verify no unhandled rejection warnings on stream error

[changeset-bot]

🦋 Changeset detected

Latest commit: 642743c

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@funkai/agents	Patch

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Project	Deployment	Actions	Updated (UTC)
funkai	Ready	Preview, Comment	Mar 15, 2026 3:31am

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• .changeset/fix-stream-unhandled-rejections.md

📝 Walkthrough

Walkthrough

Adds unhandled rejection handlers to stream result promises in two agent implementations (base and flow) to prevent unhandledRejection warnings when consumers don't await derived promises. Includes corresponding test coverage validating this safety mechanism.

Changes

Cohort / File(s)	Summary
Base Agent Rejection Handling packages/agents/src/core/agents/base/agent.ts	Attaches catch handlers to streamResult.output, streamResult.messages, streamResult.usage, and streamResult.finishReason to swallow unhandled rejections.
Flow Agent Rejection Handling packages/agents/src/core/agents/flow/flow-agent.ts	Attaches identical catch handlers to streamResult properties in both generate and stream paths.
Unhandled Rejection Safety Tests packages/agents/src/core/agents/base/agent.test.ts, packages/agents/src/core/agents/flow/flow-agent.test.ts	Adds "stream() unhandled rejection safety" test suites verifying that ignoring derived promises doesn't emit unhandledRejection events.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 50.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately summarizes the main change: preventing unhandled promise rejections in stream() by adding no-op catch handlers.
Description check	✅ Passed	The description clearly explains the changes, their purpose, and includes a test plan directly related to the changeset.

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