fix(mcp): derive server version from package

[gesh]

Problem

MCP clients and analytics can report a stale server version after the package version changes.

Why: The server duplicates package metadata in a string constant. The two values can diverge.

Refs #101133

Changes

• The server now reads its advertised version from the MCP package metadata.
• MCP Analytics: Existing $mcp_server_version events use the package version. This change adds no event or property.
• No user interface changes.

How did you test this code?

• pnpm --filter=@posthog/mcp run typecheck
• pnpm --filter=@posthog/mcp run test:hono -- tests/hono/analytics.test.ts tests/hono/request-context.test.ts

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Release status

• No feature flag controls this change
• This change is behind a feature flag and is not available to users
• This change makes a previously flagged feature available to everyone

Automatic notifications

• Publish to changelog?

Docs update

None.

🤖 Agent context

Autonomy: Human-driven (agent-assisted)

Agent: Codex, GPT-5.6

Skills invoked: writing-simplified-technical-english and writing-pr-descriptions.

The open PR search found no matching version-source fix. The change uses existing package metadata and adds no new analytics behavior.

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🤖 CI report

✅ Trunk lane — non-backend lane (svc:mcp)

This PR is assigned to the non-backend lane (svc:mcp). It does not run backend Python tests and may merge in parallel with PRs in other lanes.

✅ Duplication (Python) — clean

New Python code duplication introduced by this branch. Fails at 70+ tokens in app code, or 150+ tokens when both copies live in test files. Advisory while the gate proves itself: extract a shared helper instead of copying.

✅ Duplication (TypeScript) — clean

New TypeScript code duplication introduced by this branch. Fails at 70+ tokens in app code, or 150+ tokens when both copies live in test files. Advisory while the gate proves itself: extract a shared helper instead of copying.

[greptile-apps]

[Low risk] Updates a version constant to read from package metadata.

The version source is sound, but the test expectations should be updated before merging so the next package bump does not fail the Hono suite.

_{Reviews (1) · Last reviewed commit: "fix(mcp): derive server version from pac..."}

[greptile-apps]

Version bumps will fail tests When services/mcp/package.json is bumped, this value will change, but two assertions in request-context.test.ts still require '1.0.0'. The intended version update will fail the Hono tests. Derive those expectations from the package version too.

Prompt To Fix With AI

This is a comment left during a code review.
Path: services/mcp/src/lib/constants.ts
Line: 24

Comment:
**Version bumps will fail tests** When `services/mcp/package.json` is bumped, this value will change, but two assertions in `request-context.test.ts` still require `'1.0.0'`. The intended version update will fail the Hono tests. Derive those expectations from the package version too.

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For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

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• services/mcp/src/lib/constants.ts

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📝 Walkthrough

Walkthrough

MCP_SERVER_VERSION now uses the version from package.json instead of the hard-coded value 1.0.0.

Priority: ⬇️ Low

Merge Risk: ⚪ Minimal · up to 9ef06

The server will advertise the MCP package’s declared version instead of a separate literal. The supplied response paths use this value, and no actionable merge risk is established beyond normal checks.

🚥 Pre-merge checks | ✅ 1

✅ Passed checks (1 passed)

Check name	Status	Explanation
Description check	✅ Passed	The description is complete and relevant. It explains the problem, user-visible change, testing performed, release status, documentation status, and agent involvement. The Agent context does not inclu…

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