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The package exports Praxa-named aliases while preserving established Aura-compatible wire identifiers. Treat a host SDK’s registration call as an adapter boundary: some hosts accept raw JSON Schema while others require a library-specific schema wrapper. See Version compatibility before upgrading the package or protocol implementation.

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Compatibility rules

  1. Negotiate protocol version during initialization; never use package version as protocol version.
  2. Send MCP-Protocol-Version on later Streamable HTTP requests when required by the negotiated lifecycle.
  3. Preserve a server-issued MCP-Session-Id on later requests and start a new initialization after a session-scoped 404.
  4. Preserve all aura_* names, field names, bounds, additionalProperties, annotations, scopes, and idempotency modes.
  5. Adapt schemas at the host boundary without weakening validation.
  6. Treat host, contracts package, Gateway, and deployment versions as separate upgrade lanes.
  7. Re-run discovery, negative authorization, approval, replay, and readback tests after any lane changes.

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Upgrade matrix

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Unsupported assumptions

  • The contracts package does not start a server.
  • praxa_* tool names are not aliases for the stable wire identifiers.
  • MCP 2024-11-05 HTTP+SSE is not one of the two published Praxa contract revisions.
  • A host accepting raw JSON Schema does not prove that it enforces every bound.
  • A discovered tool does not prove that the caller is authorized to execute it.

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Rollback

Keep the previous lockfile, host configuration, and deployment version until the new combination passes. To roll back, disable newly enabled tools first, restore the previous package/host pair, revoke test grants, and repeat one read-only canary. Never rename wire tools as a rollback shortcut.
Last modified on August 14, 2026