fix(ts): keep InvokeOptions.limits caps across hook-triggered resume - #4982

Human Overview

Description

InvokeOptions.limits applies its caps to "the whole request this invoke() / stream() call starts" (strands-ts/src/types/agent.ts). A hook that sets AfterInvocationEvent.resume re-enters the agent loop inside that same public call, and every re-entry used to start a new metrics invocation entry in _stream.

This branch is rebased onto current main. Since #4667 moved limit enforcement onto InvocationContext and _shouldResume already refuses a hook resume once a cap is reached, the rebase drops the now-redundant cap guard. The remaining change starts Meter.startNewInvocation() once per public call in _streamInvocation instead of once per pass in _stream, so latestAgentInvocation, its usage, and the invocation counter describe the whole invoke() / stream() call rather than only its last pass.

Related Issues

None — no existing issue tracks this.

Documentation PR

None needed; the change keeps the metrics scope aligned with the documented per-call contract.

Type of Change

Bug fix

Testing

Added regression cases to strands-ts/src/agent/__tests__/agent.test.ts:

• A hook that resumes on every pass while each cap (turns, totalTokens, outputTokens) trips on the first pass: the call ends after a single model call. The cap suppresses the resume; the result keeps the pass's own endTurn stop reason.
• A hook that resumes once without limits: the call records one invocation entry with two cycles.

On current main the second case fails (two invocation entries); with this change it passes. The focused src/agent/__tests__ tests, ESLint, Prettier, and tsc --noEmit pass locally.

Additional Details

node strands-ts/node_modules/vitest/vitest.mjs run --root strands-ts --project unit-node src/agent/__tests__/agent.test.ts
# Tests  139 passed (139)

node strands-ts/node_modules/vitest/vitest.mjs run --root strands-ts --project unit-node src/agent/__tests__/agent.test.ts src/agent/__tests__/agent.invocation-context.test.ts
# Tests  154 passed (154)

node strands-ts/node_modules/vitest/vitest.mjs run --root strands-ts --project unit-node
# Test Files  187 passed | 5 skipped (192)
# Tests  5200 passed | 137 skipped (5337)

npx eslint src/agent/agent.ts src/agent/__tests__/agent.test.ts   # passed
npx prettier --check src/agent/agent.ts src/agent/__tests__/agent.test.ts   # passed
npx tsc --noEmit --project src/tsconfig.json   # passed

Checklist

• I have read the CONTRIBUTING document
• I have reviewed and understand every line of code in this PR, including any generated by AI tools, and I can explain why it works
• My change is focused and reasonably small; I have split unrelated work into separate PRs
• I have added any necessary tests that prove my fix is effective or my feature works
• I have updated the documentation accordingly
• I have added an appropriate example to the documentation to outline the feature, or no new docs are needed
• My changes generate no new warnings
• Any dependent changes have been merged and published

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