> ## Documentation Index
> Fetch the complete documentation index at: https://modelcontextprotocol.io/llms.txt
> Use this file to discover all available pages before exploring further.

# SDK Working Group Charter

> Charter for the MCP SDK Working Group.

## Group Type

**Working Group**

## Mission Statement

The SDK Working Group exists to keep the official MCP SDKs consistent, conformant, and current with the specification. It coordinates implementation of new protocol versions across languages, governs the [SDK Tiering System](/community/sdk-tiers), and establishes shared design patterns where sensible, so that developers get a coherent experience across SDKs while each remains idiomatic to its language.

## Scope

### In Scope

* **SDK Tiering**: Operating the [SDK Tiering System](/community/sdk-tiers), including reviewing tier advancement requests, applying relegation criteria, and maintaining the published tier assignments.
* **Official SDK Roster**: Evaluating proposals to add new official SDKs or retire existing ones.
* **Release Coordination**: Aligning Tier-1 SDK release plans with specification version dates so that protocol features land in SDKs on the timelines their tier requires.
* **Cross-SDK Design Guidance**: Recommending common patterns for SDK API surface, versioning, deprecation, error handling, and extension packaging, so that SDKs remain recognisably similar across languages while staying idiomatic.
* **Conformance Integration**: Working with the Conformance Testing project to ensure each official SDK runs the conformance suite and publishes results.
* **Maintainer Coordination**: Providing a forum for per-language SDK maintainers to share implementation experience and surface specification ambiguities back to Core Maintainers.

### Out of Scope

* **Per-SDK day-to-day maintenance**: Issue triage, PR review, and releases for an individual SDK remain the responsibility of that SDK's maintainers as listed in [MAINTAINERS.md](https://github.com/modelcontextprotocol/modelcontextprotocol/blob/main/MAINTAINERS.md).
* **Specification authorship**: Protocol changes are proposed through the [SEP process](/community/sep-guidelines) and owned by the relevant working group or Core Maintainers. The SDK WG implements accepted SEPs; it does not own spec sections.
* **Conformance test authoring**: The conformance test suite itself is owned by the [Conformance Testing](https://github.com/modelcontextprotocol/conformance) project.
* **Third-party and community SDKs**: SDKs outside the [modelcontextprotocol](https://github.com/modelcontextprotocol) organization are not governed by this group.

### Related Groups

* **Transports WG**: Transport implementations are a substantial part of every SDK. The SDK WG coordinates with the Transports WG on rollout sequencing when transport SEPs land.
* **Conformance Testing**: Tier assignments depend on conformance scores. The SDK WG consumes conformance results and feeds back gaps in test coverage.
* **All specification-producing WGs**: The SDK WG is a downstream consumer of accepted SEPs and coordinates reference-implementation timing with the originating group.

## Leadership

| Role | Name             | Organization | GitHub                                                 | Term    |
| ---- | ---------------- | ------------ | ------------------------------------------------------ | ------- |
| Lead | Felix Weinberger | Anthropic    | [@felixweinberger](https://github.com/felixweinberger) | Ongoing |

## Authority & Decision Rights

| Decision Type                            | Authority Level                                |
| ---------------------------------------- | ---------------------------------------------- |
| Meeting logistics & scheduling           | WG Leads (autonomous)                          |
| Proposal prioritization within WG        | WG Leads (autonomous)                          |
| SDK tier advancement or relegation       | WG consensus                                   |
| Cross-SDK design guidance                | WG consensus (advisory to per-SDK maintainers) |
| Per-SDK releases, versioning, API design | That SDK's maintainers (autonomous)            |
| Adding or retiring an official SDK       | WG consensus → Core Maintainer approval        |
| Changes to the tiering criteria          | WG consensus → Core Maintainer approval        |
| Scope expansion                          | Core Maintainer approval required              |
| WG Member approval                       | WG Member sponsors                             |

## Membership

WG Members are the maintainers of each official SDK as recorded in [MAINTAINERS.md](https://github.com/modelcontextprotocol/modelcontextprotocol/blob/main/MAINTAINERS.md) and the corresponding roles in [modelcontextprotocol/access](https://github.com/modelcontextprotocol/access). Maintainers of any official SDK are WG Members by default.

## Operations

| Meeting         | Frequency | Duration | Purpose                                              |
| --------------- | --------- | -------- | ---------------------------------------------------- |
| Working Session | Biweekly  | 45 min   | Release coordination, tier reviews, cross-SDK design |

Communication happens in the `#general-sdk-dev` Discord channel and the SDK Working Group category in [GitHub Discussions](https://github.com/modelcontextprotocol/modelcontextprotocol/discussions).

## Deliverables & Success Metrics

### Active Work Items

| Item                                                | Status      | Target Date | Champion            |
| --------------------------------------------------- | ----------- | ----------- | ------------------- |
| 2026-06-30 spec support across Tier-1 SDKs          | Planning    | 2026 Q3     | Per-SDK maintainers |
| Cross-SDK guidance for stateless transport adoption | In progress | 2026 Q2     | WG Leads            |
| Quarterly tier review                               | Recurring   | Quarterly   | WG Leads            |

### Success Criteria

* All official SDKs have a published tier and a passing conformance run on their default branch.
* Tier-1 SDKs ship support for each released specification version within the timeline their tier requires.
* Tier advancement and relegation decisions are recorded with rationale in GitHub Discussions.

## Changelog

| Date       | Change          |
| ---------- | --------------- |
| 2026-04-28 | Initial charter |