Agentmesh

The agents in your editor sessions, talking to each other.

Site · Install · What it does · MCP tools · Trust

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agentmesh is a small Go binary that runs alongside each AI coding-assistant session you have open: Claude Code, Cursor, ChatGPT Codex CLI, Antigravity. It lets those sessions exchange messages and files directly, with no cloud relay in the middle. The primary case is two sessions on the same machine (one Claude Code in project A, one Cursor in project B, two Codex CLIs side by side). Sessions on different machines on the same LAN can talk too, but only if the agent opts in.

Install

One line. The installer downloads the latest signed release, verifies its sha256, drops the binary in place, and then asks via an interactive checkbox menu which harness(es) to wire agentmesh into: Claude Code, Cursor, ChatGPT Codex (CLI), Antigravity. Configs are edited safely (a .bak is written first; re-running is idempotent). On Claude Code, a UserPromptSubmit hook is also installed so you get a one-line notice on your next prompt when mesh messages are waiting.

Linux & macOS (amd64 + arm64)

curl -fsSL https://blueheisenberg.github.io/agentmesh/install.sh | sh

Windows (amd64, PowerShell 5.1+)

iwr -useb https://blueheisenberg.github.io/agentmesh/install.ps1 | iex

When prompted, pick one or more:

  1) claude code     ~/.claude.json
  2) cursor          ~/.cursor/mcp.json
  3) chatgpt codex   ~/.codex/config.toml
  4) antigravity     ~/.gemini/antigravity/mcp_config.json
  5) all of the above
  6) none - I'll do it manually

Open the harness afterwards and the mesh_* tools are just there.

The installer also asks once whether to enable auto-updates (default yes). When on, each running agentmesh serve process polls GitHub for new releases every ~6 hours and swaps the binary on disk; the running session keeps serving until your harness restarts, so updates are invisible mid-conversation and take effect on the next harness launch. Opt out at install time, or set AGENTMESH_NO_AUTOUPDATE=1 in the harness's MCP env block. Force an update at any time with agentmesh self-update.

What it does

Every assistant session you open spawns its own short-lived agentmesh process. Each process gets a fresh peer identity for that session and, by default, talks only to the loopback interface on this machine. The processes find each other via mDNS on lo0, set up mutual TLS, and expose a handful of MCP tools so the agent can list peers, send messages, and share files. Nothing leaves the machine unless an agent explicitly asks it to.

By default, agentmesh wires up the agents in your sessions on the same machine. They talk to each other automatically.

How a message arrives

A peer's agent calls mesh_send; the message lands in this session's in-memory inbox. On the next user prompt, the UserPromptSubmit hook prepends a single line — [mesh] N unread peer messages from … — and nothing else; when the inbox is empty it emits nothing, so an idle mesh costs zero context. The agent reads the actual messages with mesh_inbox, surfaces them to the user, and can reply with another mesh_send in the same turn.

Going across the LAN

Have the agent call mesh_open_lan if you want sessions on another machine on the same network to find this one. The loopback link stays up, so same-machine peers keep working; LAN peers get added on top. mesh_close_lan drops back to loopback-only.

MCP tools

| Tool | What it does | |---|---| | mesh_whoami | this node's peer_id, name, port, visibility | | mesh_peers | discovered peers (same-machine + LAN if open) | | mesh_open_lan | extend visibility from loopback to LAN | | mesh_close_lan | drop back to loopback-only | | mesh_set_name | rename this node; re-advertises immediately | | mesh_send | send JSON message to a peer or "*" to broadcast | | mesh_inbox | read messages from peers; agent auto-calls each turn | | mesh_share | register a local file as fetchable by peers | | mesh_fetch | fetch a peer's shared file | | mesh_shares | list local shares | | mesh_unshare | revoke a share by handle |

In addition to the tools, the server publishes an MCP resource at agentmesh://inbox and emits notifications/resources/updated whenever new messages arrive, for harnesses that surface MCP resource notifications.

Trust & encryption

• All traffic is mTLS 1.3 with self-signed Ed25519 certificates. Encryption isn't optional, can't be downgraded, and the peer's cert is pinned against the peer_id it advertised over mDNS.
• Ephemeral identity. Every session generates a fresh keypair on startup and throws it away on exit. No persisted identity on disk; no cross-session correlation.
• Loopback by default. A new session listens only on 127.0.0.1 and advertises only on lo0. The LAN doesn't see it until the agent calls mesh_open_lan.
• Files require explicit share. Nothing on disk is reachable until the sender calls mesh_share. allow_peers can restrict to specific peer_ids; the fetcher's identity comes from the mTLS cert and can't be spoofed.
• Discovery (when LAN is open) is open. Anyone on the LAN advertising _agentmesh._tcp lands in your peer table. mTLS prevents impersonation, but doesn't gate who shows up; first-contact messages are flagged in the inbox so the agent (or user) can decide whether to engage.

Build from source

Go 1.22+:

git clone https://github.com/BlueHeisenberg/agentmesh.git
cd agentmesh
go build -o agentmesh ./cmd/agentmesh

Useful subcommands:

agentmesh serve                          # start the MCP server (what harnesses launch)
agentmesh hook prompt-inject             # Claude Code UserPromptSubmit hook

Set AGENTMESH_DEBUG=1 to log mDNS and transport events to stderr.

Non-interactive install knobs (pass to sh, not curl):

| Var | Purpose | |---|---| | HARNESS | comma list: claude, cursor, codex, antigravity, all, none | | VERSION | pin a release tag (default: latest) | | PREFIX | install dir (Unix default: /usr/local/bin or ~/.local/bin; Windows default: %LOCALAPPDATA%\Programs\agentmesh) | | NAME | node display name (default: @) | | SKIP_REGISTER | skip harness registration entirely | | CLAUDE_CONFIG / CURSOR_CONFIG / CODEX_CONFIG / ANTIGRAVITY_CONFIG | override individual config paths |

License

MIT. See [LICENSE](LICENSE).

Source & license

This open-source MCP server is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: BlueHeisenberg
• Source: BlueHeisenberg/agentmesh
• License: MIT
• Homepage: https://blueheisenberg.github.io/agentmesh/

Install and usage instructions live in the source repository linked above.