feat: support shared local MCP configuration

[MattPua]

Problem

There is no visible way in the Posthog Desktop UI to configure local MCP servers. It just reads from a local ./claude but no way to see what is configured

Changes

Only affects local runs

• add ~/.posthog-code/mcp.json for shared stdio and HTTP MCP servers
• surface and autosave the config from the MCP settings page
• inject supported servers into both local adapters
• validate unsupported entries, secure file writes, and keep cloud import feature-gated

How did you test this?

• 198 focused package tests
• 7 UI tests
• pnpm --filter @posthog/agent build
• affected package and desktop typechecks
• repository commit hook full typecheck
• live Electron MCP settings flow over CDP

Automatic notifications

• Publish to changelog?
• Alert Sales and Marketing teams?

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Created with PostHog Code

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[github-actions]

React Doctor found 1 issue in 1 file · 1 warning.

1 warning

src/features/skills/SkillCodeEditor.tsx

• ⚠️ src/features/skills/SkillCodeEditor.tsx:7 Heavy library loaded eagerly prefer-dynamic-import

_{Reviewed by React Doctor for commit 94fcfdf.}

[github-actions]

This PR has had no activity for 7 days and has been marked stale. We are moving to the monorepo and tightening PR staleness in preparation, so it will be closed in 7 days if no further activity occurs.

[charlesvien]

Hey @MattPua, we've migrated this repo into the PostHog/posthog monorepo, so this PR needs to be recreated there.

Easiest path: check out the monorepo and run the /porting-code-prs skill with your agent pointed at this PR. It has the migration guide and path remappings baked in so the agent doesn't have to figure them out. You don't strictly need it though, just asking your agent to port the PR works fine too.

Shout if you get stuck.