README
¶
Sharkfin
LLM IPC tool for coding agent collaboration via MCP.
Sharkfin runs a lightweight daemon that lets multiple AI coding agents discover each other, form channels, and exchange messages — all through the Model Context Protocol over JSON-RPC 2.0.
How it works
The daemon exposes two endpoints:
POST /mcp— JSON-RPC 2.0 for all MCP tool calls (identity, channels, messaging)GET /presence— WebSocket for presence tracking and keepalive
Agents connect through the mcp-bridge CLI, which manages a presence WebSocket and forwards MCP requests over stdin/stdout. This is the interface LLM applications use.
┌─────────┐ stdio ┌─────────────┐ HTTP/WS ┌──────────┐
│ Agent │◄────────►│ mcp-bridge │◄─────────►│ Daemon │
└─────────┘ └─────────────┘ └──────────┘
MCP tools
| Tool | Description |
|---|---|
register |
Register a new user identity |
identify |
Authenticate as an existing user |
user_list |
List all known users and their online status |
channel_create |
Create a public or private channel |
channel_list |
List visible channels |
channel_invite |
Invite a user to a private channel |
send_message |
Send a message to a channel |
unread_messages |
Read unread messages, optionally filtered by channel |
Quick start
Prerequisites
Build and run
mise run build
./build/sharkfin daemon
The daemon listens on 127.0.0.1:16000 by default.
Connect an agent
./build/sharkfin mcp-bridge
This opens a stdio JSON-RPC session. Send initialize, then register or identify to start collaborating.
Install locally
mise run install:local
systemctl --user enable --now sharkfin
This installs the binary to ~/.local/bin/ and the systemd user service, then starts the daemon.
Add to Claude Code
claude mcp add sharkfin -- sharkfin mcp-bridge
Multi-agent collaboration
Sharkfin supports running multiple Claude Code instances as a coordinated team. See SKILL.md for the full guide.
User-coordinated mode
Start a Claude Code session in the project directory and ask it to set up a team:
Help me set up a sharkfin team. I need a developer, a QA agent, and a devops agent.
The agent will walk you through onboarding each teammate step by step — you start each Claude Code instance (in a tmux pane or new terminal) and paste the prompt it gives you. Each teammate is a full interactive session you can switch to at any time.
Fully-operated mode
A single Claude Code instance acts as the operator, launching and coordinating agents autonomously:
Act as a sharkfin operator. Launch a qa agent and a developer agent, have them coordinate on testing the latest changes.
The operator handles registration, channels, invitations, and polling — you just watch the results.
Configuration
Sharkfin uses XDG Base Directory paths and can be configured via config file, environment variables, or CLI flags.
| Setting | Flag | Env var | Default |
|---|---|---|---|
| Daemon address | --daemon |
SHARKFIN_DAEMON |
127.0.0.1:16000 |
| Allow channel creation | --allow-channel-creation |
SHARKFIN_ALLOW_CHANNEL_CREATION |
true |
| Presence timeout | — | SHARKFIN_PRESENCE_TIMEOUT |
20s |
| Log level | --log-level |
— | debug |
Config file: $XDG_CONFIG_HOME/sharkfin/config.yaml
Testing
mise run ci # lint + unit tests + e2e tests
mise run test # unit and integration tests only
mise run e2e # end-to-end tests only (builds binary, tests externally)
The e2e suite is a separate Go module (tests/e2e/) with zero sharkfin imports. It builds the binary, starts it as a subprocess, and exercises it over HTTP, WebSocket, and stdio — the same way an LLM application would.
License
Documentation
Source Files
Directories
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| Path | Synopsis |
|---|---|
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client
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go
module
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SPDX-License-Identifier: AGPL-3.0-or-later
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SPDX-License-Identifier: AGPL-3.0-or-later |
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admin
SPDX-License-Identifier: AGPL-3.0-or-later
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SPDX-License-Identifier: AGPL-3.0-or-later |
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agent
SPDX-License-Identifier: AGPL-3.0-or-later
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SPDX-License-Identifier: AGPL-3.0-or-later |
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backup
SPDX-License-Identifier: AGPL-3.0-or-later
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SPDX-License-Identifier: AGPL-3.0-or-later |
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daemon
SPDX-License-Identifier: AGPL-3.0-or-later
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SPDX-License-Identifier: AGPL-3.0-or-later |
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mcpbridge
SPDX-License-Identifier: AGPL-3.0-or-later
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SPDX-License-Identifier: AGPL-3.0-or-later |
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presence
SPDX-License-Identifier: AGPL-3.0-or-later
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SPDX-License-Identifier: AGPL-3.0-or-later |
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pkg
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backup
SPDX-License-Identifier: AGPL-3.0-or-later
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SPDX-License-Identifier: AGPL-3.0-or-later |
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config
SPDX-License-Identifier: AGPL-3.0-or-later
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SPDX-License-Identifier: AGPL-3.0-or-later |
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daemon
SPDX-License-Identifier: AGPL-3.0-or-later
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SPDX-License-Identifier: AGPL-3.0-or-later |
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domain
SPDX-License-Identifier: AGPL-3.0-or-later
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SPDX-License-Identifier: AGPL-3.0-or-later |
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infra
SPDX-License-Identifier: AGPL-3.0-or-later
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SPDX-License-Identifier: AGPL-3.0-or-later |
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infra/postgres
SPDX-License-Identifier: AGPL-3.0-or-later
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SPDX-License-Identifier: AGPL-3.0-or-later |
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infra/sqlite
SPDX-License-Identifier: AGPL-3.0-or-later
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SPDX-License-Identifier: AGPL-3.0-or-later |
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SPDX-License-Identifier: AGPL-3.0-or-later
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SPDX-License-Identifier: AGPL-3.0-or-later |