MCP Tools Overview: All 7 AgentRelay Tools

A guide to all seven AgentRelay MCP tools — how agents invoke them, what each tool does, and how they map to the handoff lifecycle.

AgentRelay exposes its functionality as seven MCP tools that your coding agent (Claude Code, Codex CLI, or any MCP-compatible harness) can call by name. When you tell your agent “send a handoff to frank@acme”, it translates that instruction into a handoff_to_teammate tool call. The MCP server handles authentication, input validation with zod, idempotency key generation, and the actual A2A JSON-RPC call to the relay — your agent never speaks to the relay directly.

The seven tools

Tool	Side	One-line description
handoff_to_teammate	Sender	Package context and send a handoff to a teammate’s agent
check_inbox	Receiver	List pending and active handoffs addressed to you
accept_handoff	Receiver	Pull full thread context into the current session
view_thread	Both	Read a thread’s messages and artifacts without accepting
send_message	Both	Append a reply to an existing thread
complete_handoff	Receiver	Mark a thread completed and return a result summary
list_teammates	Both	Discover registered teammates by role, skill, or repo

How agents invoke tools

Your agent receives natural language instructions and maps them onto tool calls. The MCP protocol handles the translation — you do not need to write JSON or call any API. Below are examples of how each tool is typically invoked.

handoff_to_teammate — kick off a new thread

“Send a handoff to bob@acme. Tell him I refactored the /users endpoint — the response is now paginated. Attach the diff.”

check_inbox — scan for new work

“Check my inbox for pending handoffs.” “Are there any accepted threads that have new messages?”

accept_handoff — pull a thread into the session

“Accept handoff 01HXYZ and load all the context.”

view_thread — read without acting

“Show me the current state of thread 01HXYZ.” “What did bob say in the latest message on that thread?”

send_message — reply in-thread

“Reply to thread 01HXYZ: I need the expected response shape for the /search endpoint before I can complete this.”

complete_handoff — close a thread

“Mark handoff 01HXYZ complete. Summary: updated the API client to handle paginated responses; all tests pass.”

list_teammates — find who owns something

“List all backend teammates.” “Who owns the apps/web/ directory?”

Handoff lifecycle

The seven tools map onto four phases of a handoff’s lifetime:

[Sender]                         [Receiver]
    │                                 │
    │  handoff_to_teammate            │
    │─────────────────────────────────▶  thread created (status: pending)
    │                                 │
    │  view_thread (optional)         │  check_inbox
    │◀─────────────────────────────── │  accept_handoff  (status: accepted)
    │                                 │
    │  send_message (if question)     │  send_message
    │◀────────────────────────────────▶  back-and-forth replies
    │                                 │
    │                                 │  complete_handoff (status: completed)
    │◀─────────────────────────────── │

list_teammates sits outside the lifecycle — it is a discovery tool you can call at any time to find the right recipient before sending.

Tool reference pages

handoff_to_teammate

Send structured context — diffs, contracts, questions — to a teammate’s agent

check_inbox, accept_handoff, and more

The full receive-side workflow: inbox, accept, reply, and complete

list_teammates

Discover teammates by role, skill, or repository ownership

Setup guide

Wire the MCP server into Claude Code or Codex CLI

The propose_action intent and the draft_proposed_action tool are v0.1.5 features. Both are described inline throughout these pages where they affect an existing tool’s behavior. Standalone documentation for draft_proposed_action will ship with the v0.1.5 release notes.