concordia-protocol — Claude Code plugin: what it does, how to install
Equips Claude Code with structured negotiation capabilities for autonomous agents. Handles multi-attribute offers, discovery, and signed session receipts.
/plugin marketplace add anthropics/claude-plugins-community
/plugin install concordia-protocol@claude-communityWhat concordia-protocol does
The plugin exposes 59 MCP tools across nine categories, covering negotiation, reputation, discovery, and relay messaging. It enforces a formal six-state session lifecycle. Every transcript entry uses Ed25519 signatures and hash chains to generate tamper-resistant transaction receipts.
Running this setup requires Python 3.10 or newer. Because the plugin executes concordia-mcp-server over stdio transport, install the Python package using pip install "concordia-protocol[server]". Installing it without the [server] extra causes the server binary to crash on startup due to missing MCP dependencies.
The four Sanctuary bridge tools remain optional and only take effect when Sanctuary is active. If an external peer lacks Concordia support, the protocol degrades gracefully to standard interaction.
What it helps with
- exchange structured multi-attribute counter-offers between autonomous agents
- generate verifiable session receipts backed by Ed25519 signatures and hash chains
- discover suitable counterparties using the want/have registry
- verify agent mandates and portable reputation scores before closing deals
Example prompts for the agent
- Register our data extraction task in the Concordia want registry.
- Discover available peer agents for this job and request their initial terms.
- Counter-offer the proposed rate and sign the final agreement receipt.
How to install concordia-protocol
Plugin marketplace
/plugin marketplace add anthropics/claude-plugins-community/plugin install concordia-protocol@claude-communityStep by step, with commands for each platform: Claude Code plugins: marketplaces, installing, and building your own
Questions about concordia-protocol
How to install concordia-protocol in Claude Code?
First install the Python package via pip install "concordia-protocol[server]". Then run /plugin marketplace add anthropics/claude-plugins-community followed by /plugin install concordia-protocol@claude-community in Claude Code.
What does concordia-protocol do?
It provides a structured negotiation framework for autonomous agents, supporting multi-attribute proposals, peer discovery, and cryptographically signed session receipts via 59 MCP tools.
Why does concordia-mcp-server exit immediately on startup?
The Python package was likely installed without the [server] extra. Without that flag, required MCP dependencies are missing and the binary cannot run.
Source text
plugin · Apache-2.0
# Concordia Protocol Plugin Structured negotiation for autonomous agents, as a Claude Code and Cowork plugin (Concordia v0.10.0). ## What it does Gives your agent binding commitments, multi-attribute offers, counter-offers, session receipts, portable reputation, agent discovery, want/have matching, relay-mediated negotiation, and graceful degradation for peers that do not speak Concordia. ## Installation The plugin starts the Concordia MCP server with the `concordia-mcp-server` command (stdio transport), so install the Python package with its server extra first: ```bash pip install "concordia-protocol[server]" concordia-mcp-server --version # should print 0.10.0 ``` Then install the plugin from the marketplace: ```bash /plugin marketplace add eriknewton/claude-plugins /plugin install concordia-protocol@newton-agent-tools ``` Without the `[server]` extra the command is installed but exits at start, because the MCP library it needs is missing. ## Requirements - Python 3.10 or later - `pip install "concordia-protocol[server]"` ## Tools provided 59 MCP tools across 9 categories: Negotiation (11), Session receipts and bundles (6), Competence proofs (2), Reputation (6), Discovery and agent profiles (8), Want registry (10), Relay (10), Sanctuary bridge (4), Mandate and approval verification (2). The set is 55 `concordia_*` tools plus 4 `agent_*` profile-discovery tools registered via `register_discovery_tools()`. See the skill documentation for the complete list. Concordia works on its own. The Sanctuary bridge tools are optional and only matter when Sanctuary also runs. ## License Apache-2.0
© eriknewton · Apache-2.0 · eriknewton/concordia-protocol
