Mastra Core 1.78 adds agent scopes and typed signal queues

Mastra published @mastra/core 1.78.0 on October 16, 2026.

What changed

• Agent scopes carry identities such as organization, resource and thread across calls. Conflicting memory routing values return an error rather than silently choosing one, and resumed runs preserve their recorded scopes.
• queueSignal keeps a queued signal's type, tag and attributes instead of flattening it into a user message. Signal metadata is also attached to the agent-run trace.
• Trace aggregation gains server, client and React support, with discovery for supported dimensions and measures.
• Stored input, output and error previews let trace-list views avoid loading complete payloads. This architectural change is not an independently measured speed result.

Upgrade notes

The maintainers require upgrading @mastra/server alongside the scopes change. They warn that old or custom adapters may not be detected by the compatibility guard. Use trusted identity middleware, not arbitrary request fields, when assigning scopes.

The release also deprecates older preview helpers and documents Factory session-mode and credential-resolution changes. Review those breaking-change notes before adoption.

License and cost

The release-tag license is Apache-2.0 outside directories named ee; enterprise directories and third-party components have separate licenses. Software licensing is separate from hosted-service, inference and infrastructure charges; this note does not claim a free hosted tier.

These changes are reported by the maintainers. We have not independently benchmarked the release.

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