Mastra shipped @mastra/core 1.71.0 on 2026-09-24: agent.stream starts each tool as soon as its args complete (eagerToolExecution on by default), cutting idle seconds on multi-tool steps; adds planTraceAggregate(), observability getFeatures discovery/feedback flags, and RE2-backed dataset schema regexes to close a DoS vector.

Key Takeaways

  • ✓Default: tools start when their streamed args complete; opt out with `eagerToolExecution: false` (#25005)
  • ✓Observability stores declare discovery + feedback via `getFeatures()` (#25008, #25020)
  • ✓`planTraceAggregate()`: ≤365d range, ≤1000 buckets, ≤10,000 rows (#24868)
  • ✓Dataset schema regexes run on RE2; unsupported lookarounds/backrefs rejected (#25044)
  • ✓Upgrade: `npm i @mastra/[email protected]`
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Project Links & Resources

Direct Access
Direct access to official project resources and documentation
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@mastra/core 1.71.0 on npm
www.npmjs.com/package/@mastra/core/v/1.71.0
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packages/core CHANGELOG 1.71.0
github.com/mastra-ai/mastra/blob/main/packages/core/CHANGELOG.md
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PR #25005 eager tool execution
github.com/mastra-ai/mastra/pull/25005
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agent.stream reference
mastra.ai/reference/streaming/agents/stream
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PR #24868 planTraceAggregate
github.com/mastra-ai/mastra/pull/24868
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#25044
github.com/mastra-ai/mastra/pull/25044
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#25008
github.com/mastra-ai/mastra/pull/25008
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#25020
github.com/mastra-ai/mastra/pull/25020
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In-Depth Technical Analysis

Background

Multi-tool agent steps often idle while the model finishes streaming even after each tool-call's arguments are complete. Observability UIs also lack a shared capability advertisement for custom stores. Mastra 1.71.0 targets both.

Architecture

agent.stream enables eager tool execution by default (#25005): a tool starts when its args complete. Approval/suspend/provider-client/background tools and certain concurrency/output-processor paths still wait for the model. Opt out with eagerToolExecution: false. ObservabilityStorage getFeatures() can advertise discovery + feedback (#25008/#25020). planTraceAggregate() returns a TrustedTraceAggregatePlan after validation (#24868).

Benchmarks

No public SWE scores. Documented aggregate limits: ≤365-day range, ≤1000 buckets, ≤10,000 rows. ~57 commits vs 1.70.0 on the monorepo compare. Dataset regexes move to RE2 (#25044).

Get started

npm i @mastra/[email protected], read the core CHANGELOG, and declare only supported observability features in custom stores.