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Group Type

Working Group

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Mission Statement

The Transports Working Group evolves MCP transport bindings and transport-adjacent protocol architecture so implementations remain interoperable, scalable, reliable, and easy to operate across local and remote deployments. The WG produces transport proposals, SEPs, implementation evidence, and guidance. The working group repository and its upstream charter maintain the WG’s current technical focus, proposal strategy, and supporting detail within these boundaries.

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Scope

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In Scope

  • Transport Bindings: Framing, delivery, request and envelope metadata, cancellation and termination, connection lifecycle, backward compatibility, and the behavior of existing and future MCP transports. The current specification’s transport overview defines the boundary between a transport binding and core protocol semantics.
  • Scalability and Reliability: Transport-level connection management, resource efficiency, multiplexing, load distribution, error handling, reconnection, resumption, and the delivery and ordering guarantees offered by a binding.
  • Transport-Adjacent Protocol Architecture: Protocol-wide message-flow concerns required for scalable, interoperable bindings, including request association, per-request metadata, stateless operation, and migration from legacy initialization and transport-session models.
  • Transport Security: Binding and envelope security requirements such as Origin validation, TLS, mTLS, and certificate handling, coordinated with the Security IG. Credential carriage is coordinated with the Auth IG.
  • Validation and Guidance: Reference implementations, experiments, implementation evidence, and documentation needed to evaluate proposals and help implementers adopt agreed transport behavior. Supporting material is maintained in the upstream documentation. The WG contributes transport scenarios and requirements to the Conformance Testing project, whose maintainers own the conformance suite.
  • Cross-Cutting Coordination: Transport implications of work owned by other MCP groups, without taking ownership of their application-layer features.
The upstream scope statement provides supporting context but cannot expand the boundaries in this charter.

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Out of Scope

  • Application-layer behavior for MCP primitives such as tools, resources, prompts, tasks, agents, or events, including application state, application-session meaning, task lifecycle, and event or subscription semantics. The WG coordinates where those features depend on binding or message-flow behavior.
  • Domain-specific extensions and implementation-specific product or business concerns.
  • SDK APIs and implementation details unrelated to transports.
  • Authorization protocol mechanics, credential and token semantics, application identity, and authorization policy. The WG coordinates with the relevant groups on how bindings carry agreed authorization data.
  • Ownership of the MCP conformance suite. The WG contributes transport requirements and scenarios in coordination with its maintainers.
  • SDK WG: Official SDKs implement transport changes; the groups coordinate on feasibility, reference implementations, and rollout sequencing.
  • Agents WG: The Agents WG owns Tasks and durable execution; the groups coordinate where these depend on multi-round-trip requests, request association, stateless operation, or binding behavior.
  • Triggers and Events WG: Event callbacks, subscriptions, and application-level delivery semantics are owned by that group; Transports owns binding-specific carriage and guarantees.
  • Auth IG and Security IG: The groups coordinate on credential carriage and transport wire security while authorization mechanics and broader security requirements remain with the respective IGs.

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Leadership

The current WG Lead is Kurtis Van Gent.

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Authority & Decision Rights

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Membership

Current WG Members are listed in the upstream group membership roster.

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Operations

The WG holds a regular weekly meeting, with the current time and joining details listed at meet.modelcontextprotocol.io. Topics are discussed asynchronously in #transports-wg on the MCP Discord. Work follows a problem-first workflow:
  1. Create a core problem statement in the working group repository to align the WG on the problem and its requirements.
  2. Work with other interested participants to define a solution.
  3. Review and iterate on the solution to address WG feedback.
  4. After the WG reaches consensus under its decision-making process, present the solution to Core Maintainers as an SEP through the SEP process.

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Resources

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Deliverables & Success Metrics

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Active Work Items

See open pull requests and the roadmaps/ directory.

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Success Criteria

  • Adopted transport-agnostic protocol behavior remains consistent across transports, while binding-specific differences are explicit and validated by implementation evidence and applicable conformance scenarios.
  • Transport changes that affect official SDKs are coordinated with the SDK WG and have clear implementation guidance.
  • Decisions, proposal status, and supporting rationale remain publicly discoverable in or linked from the working group repository.

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Changelog