fix: add production rewrite for /api/mcp to mcp.tempo.xyz

[jxom]

Problem

The Try the MCP server explorer on /developers/docs/guide/using-tempo-with-ai#connect-to-tempos-mcp-server fails in production.

TempoMcpExplorer POSTs to /api/mcp. This works locally because vite.config.ts proxies /api/mcp → https://mcp.tempo.xyz, but production has no equivalent rewrite. The request falls through to the marketing app, which 308-redirects /api/mcp → /api/mcp/, which then 404s.

POST /api/mcp  →  308  →  /api/mcp/  →  404.html

Fix

Add a Vercel reverse-proxy rewrite mirroring the dev proxy:

{ "source": "/api/mcp", "destination": "https://mcp.tempo.xyz/" }

A same-origin reverse proxy is required (rather than calling mcp.tempo.xyz directly from the browser) because mcp.tempo.xyz does not return access-control-allow-origin on POST responses, so a direct cross-origin fetch is blocked by CORS.

Verification

• Root-path rewrites from this vercel.json are confirmed live in prod (the sibling /ingest/* → PostHog rewrite returns 200), so this rewrite will take effect.
• Full end-to-end verification requires a deploy/preview.

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Project	Deployment	Actions	Updated (UTC)
tempo-docs	Ready	Preview, Comment	Jul 1, 2026 8:10pm

[jxom]

Wrong repo: tempo.xyz/api/mcp is served by the tempo-web project, so a rewrite in the docs repo's vercel.json never runs for that root path. The playground's fetch('/api/mcp') is root-absolute and hits tempo-web. Moving the fix to tempo-web/vercel.json (alongside the existing /ingest proxy).