The 3 real inter-agent protocols this ecosystem actually runs on.
This repo and its polyrepo sibling don't use one inter-agent protocol -- they use three, for three different jobs: A2A hands a task to an independently-hosted agent over HTTP; MCP exposes tools/resources to a model over stdio or Streamable HTTP; e2m coordinates multiple domain coworkers asynchronously via a durable JSONL mailbox. This site catalogs all three side by side -- purpose, transport, real SDK/implementation, and exactly where each one is actually used in this codebase -- rather than leaving that comparison as something only reconstructable by reading three different parts of CLAUDE.md.
This site compares what each protocol is for and who actually calls it. Wire-level a2a.terse.v1 YAML spec syntax lives on the sibling site subagentspec.com instead -- deliberately not duplicated here.
Every row cites a real CLAUDE.md section or repo file -- crates/mcp-server, crates/a2a-bridge, workers/web, the sister repo's coworkers/ monorepo. No invented protocol, no approximate citation.
A2A and MCP are production in this repo today. e2m is real, but its implementation lives entirely in the polyrepo sibling (knowledge-engineering) -- tagged sister-repo, not misrepresented as local.
Live catalog
All 3 rows are seeded verbatim from this repo's own CLAUDE.md into this Worker's own D1 database (protocols). Browse the catalog → or hit the JSON API.