TypeScript SDK — Tier 1 Assessment

SDK: modelcontextprotocol/typescript-sdk
Version: 1.27.0 (branch: v1.x)
Assessed: 2026-02-18
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. One informational extension scenario fails (auth/cross-app-access-complete-flow) — not scored for tier per conformance testing rules.

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

3. Issue Triage — ✅ 97.4% (187/192)

187 of 192 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. Previously mislabeled P0s (v2 roadmap items) have been re-triaged.

Evidence: Open P0 issues (should show 0 results)

5. Stable Release — ✅ 1.27.0

Published on npm and GitHub Releases. Breaking change policy documented in VERSIONING.md — SemVer 2.0.0 with 7 explicit breaking change categories.

6. Spec Tracking — ✅ Same-day

SDK v1.23.0 released 2025-11-25 21:14 UTC, same day as the spec 2025-11-25 tag (21:14 UTC). Automated spec type tracking via the update-spec-types workflow (runs nightly).

7. Documentation — ✅ 48/48 features

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

• docs/server.md — Tools, resources, prompts, completions, logging, transports
• docs/client.md — Client transports, roots, OAuth
• docs/capabilities.md — Sampling, elicitation
• docs/protocol.md — Ping, progress, cancellation, pagination, capability negotiation, JSON Schema 2020-12

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 monthly GitHub Actions updates.

9. Roadmap — ✅

ROADMAP.md — Spec implementation tracked via per-revision GitHub Project boards. v2 SDK milestones: Alpha ~mid-March 2026, Beta ~May 2026, aligned with next spec release.

10. Versioning Policy — ✅

VERSIONING.md — SemVer 2.0.0 adherence. Enumerates 7 breaking change categories and 7 non-breaking categories. Four communication mechanisms: release notes, @deprecated annotations, migration guides, PR labels.

Raw Assessment Output

• Full assessment report — output of mcp-sdk-tier-audit skill
• Summary report — markdown summary
• Remediation report — confirms no actions needed
• tier-check CLI output — deterministic scorecard

Reproduce This Assessment

Prerequisites

• Node.js >= 20
• GitHub CLI (gh) authenticated (gh auth login)
• Git

Quick check (repository health only, ~30 seconds)

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

Full check (with conformance tests, ~5 minutes)

# Terminal 1: Clone and start the SDK's conformance server
git clone https://github.com/modelcontextprotocol/typescript-sdk.git
cd typescript-sdk
git checkout v1.x
npm install
npm run build
npm run test:conformance:server:run
# Server starts on http://localhost:3000/mcp

# Terminal 2: Run the full tier-check
cd conformance
npm run --silent tier-check -- \
  --repo modelcontextprotocol/typescript-sdk \
  --branch v1.x \
  --conformance-server-url http://localhost:3000/mcp \
  --client-cmd 'npx tsx ../typescript-sdk/test/conformance/src/everythingClient.ts'

Output formats

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

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

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