Python SDK — Tier 1 Assessment

SDK: modelcontextprotocol/python-sdk
Version: 1.26.0 (branch: v1.x)
Assessed: 2026-02-23
Requested tier: Tier 1
Tool: @modelcontextprotocol/conformance tier-check

Result

All Tier 1 requirements are met.

Requirements Detail

1. Server Conformance — ✅ 30/30 (100%)

Tested against spec versions 2025-06-18 and 2025-11-25 using the conformance test suite. CI runs continuously via the conformance workflow.

Evidence: Full assessment report · CLI output · How to run it yourself

2. Client Conformance — ✅ 20/20 (100%)

Core: 4/4, Auth: 16/16 scored. Two informational scenarios fail (auth/resource-mismatch on draft, auth/cross-app-access-complete-flow on extension) — not scored for tier per conformance testing rules.

Evidence: Full assessment report · CLI output · How to run it yourself

3. Issue Triage — ✅ 96.8% (241/249)

241 of 249 issues triaged within 2 business days. All 12 required labels are present.

Evidence: Open issues without any triage label

4. P0 Resolution — ✅ 0 open

No open P0 issues. 1 total P0 was closed within 7 days.

Evidence: Open P0 issues (should show 0 results)

5. Stable Release — ✅ 1.26.0

Published on PyPI and GitHub Releases. Breaking change policy documented in VERSIONING.md — SemVer 2.0.0 with enumerated breaking change categories.

6. Spec Tracking — ✅ 7-day gap

SDK v1.23.0 released 2025-12-02 13:28 UTC, 7 days after the spec 2025-11-25 tag (21:17 UTC).

7. Documentation — ✅ 48/48 features

All 48 non-experimental MCP features documented with code examples across docs/:

• docs/server.md — Tools, resources, prompts, completions, elicitation, logging, transports
• docs/client.md — Client transports, roots, OAuth, sampling
• docs/protocol.md — Ping, cancellation, capability negotiation, pagination, JSON Schema 2020-12
• docs/low-level-server.md — Low-level server API, stdio transport, pagination

8. Dependency Policy — ✅

DEPENDENCY_POLICY.md — Conservative update philosophy: dependencies updated only for security vulnerabilities, bugs, or needed features. GitHub security alerts enabled. Dependabot configured for automated updates.

9. Roadmap — ✅

ROADMAP.md — Spec implementation tracked via per-revision GitHub Project boards. v2 SDK milestones documented with target dates.

10. Versioning Policy — ✅

VERSIONING.md — SemVer 2.0.0 adherence. Enumerates breaking and non-breaking change categories. Communication via changelog, deprecation warnings, migration guides, and PR labels.

Raw Assessment Output

• Full assessment report — JSON assessment with full conformance details
• Summary report — markdown summary
• tier-check CLI output — deterministic scorecard

Reproduce This Assessment

git clone https://github.com/modelcontextprotocol/conformance.git
cd conformance
npm install
npm run build
npm run --silent tier-check -- --repo modelcontextprotocol/python-sdk --branch v1.x --skip-conformance

# Terminal 1: Clone and start the SDK's conformance server
git clone https://github.com/modelcontextprotocol/python-sdk.git
cd python-sdk
git checkout v1.x
uv sync --frozen --package mcp-everything-server
uv run --frozen mcp-everything-server --port 3001
# Server starts on http://localhost:3001/mcp

# Terminal 2: Run the full tier-check
cd conformance
npm run --silent tier-check -- \
  --repo modelcontextprotocol/python-sdk \
  --branch v1.x \
  --conformance-server-url http://localhost:3001/mcp \
  --client-cmd 'uv run --frozen python ../python-sdk/.github/actions/conformance/client.py'

# Terminal output (default)
npm run --silent tier-check -- --repo modelcontextprotocol/python-sdk --skip-conformance

# Markdown report
npm run --silent tier-check -- --repo modelcontextprotocol/python-sdk --skip-conformance --output markdown

# Machine-readable JSON
npm run --silent tier-check -- --repo modelcontextprotocol/python-sdk --skip-conformance --output json