Let Claude Code, Codex, Cursor, Gemini CLI, and Grok Build talk to each other.
The open-source, local-first communication and coordination layer for AI coding agents. Send live messages across harnesses, detect overlapping work before agents edit, share decisions, and hand off tasks with evidence - through one MCP server.
Demo · Quick start · Supported agents · Website · Contributing
Two agents in different harnesses can discover each other, exchange messages, and divide work without a human relaying context between them:
Claude Code → Concord Claim src/app/page.tsx
Codex → Concord Claim src/app/page.tsx
Concord → Codex Overlap: Claude Code already owns this file
Codex → Claude I'll take src/app/api instead. Does that work?
Claude → Codex Yes. I'll keep the page and use your API contract.
Run the real Claude Code ↔ Codex demo to watch both agents resolve an overlapping claim through a live prompt/reply, build a playable app, transfer ownership, and hand the result to an independent reviewer.
npm install -g @concord-ai/concord-mcp
cd /path/to/your/repository
concord setup
Restart your agent clients, then ask two of them to work in the same repository. Concord gives them a shared workspace and makes reachable sessions available for direct prompts and replies.
What concord setup #
changes
concord setup
creates the local .concord/
workspace, registers the MCP server
for Claude, Cursor, Gemini, Grok, and Codex (.mcp.json
, .cursor/mcp.json
,
.gemini/settings.json
, .grok/config.toml
, and ~/.codex/config.toml
) and writes
Concord's tool instructions into your client configs (CLAUDE.md
, AGENTS.md
,
.codex/
, .cursor/rules/
). It merges into existing config rather than replacing it and is safe to re-run.
Setup also detects supported clients and attempts to install their global Concord
adapters independently. Use --no-adapters
to skip that step or
--require-adapters
in managed installs that should fail on degraded support.
Pass --no-mcp
to write only the workspace and instructions while managing MCP registration yourself.
| Agent | Integration guide |
|---|---|
| Claude Code | |
Setup and deliverySetup and deliverySetup and deliverySetup and deliveryThere is no universal
/concord
slash command — commands are client-specific. Concord works through MCP tools plus the installed instructions on any MCP-capable client.
Live delivery depends on the receiving harness and session state. Run
concord adapters status
to see which installed agents are reachable and how messages will be delivered.
Messaging gets agents talking. Concord's shared work-state keeps the resulting collaboration reliable after the message is delivered.
| Without Concord | With Concord |
|---|---|
| Agents cannot contact peers in another harness | Agents send direct, replyable prompts across supported clients |
| Agents discover collisions after editing | Agents claim files and modules before work begins |
| Context disappears when a session ends | Decisions, assumptions, and findings stay attached to the task |
| Ownership is implied by chat history | Assignments and handoffs are explicit and acknowledged |
| Humans reconstruct progress from branches and diffs | Review packets arrive with scope, tests, risks, and provenance |
Concord is not another autonomous agent or orchestrator. It is the shared layer around your agents: presence, messaging, task memory, ownership, handoffs, and review state through one small MCP server.
| Tool | Purpose |
|---|---|
start_work |
|
| registers presence, claims or accepts one task, and reports scope overlaps before editing | |
inspect_work |
|
| reads workspace/task state, an agent inbox/outbox, or a durable prompt/reply thread | |
update_work |
|
| records task context or immediately prompts/replies to another promptable workspace agent | |
transfer_work |
|
| assigns, accepts, declines, releases, reassigns, offers handoffs, or reopens versioned work | |
finish_work |
|
| records evidence and optionally marks a task review-ready, complete, or closed |
Writes accept an agent_id
, which keeps presence live just by working.
inspect_work
shows who is here and flags stale claims — an active claim whose owning agent has gone away without handing off.
For live agent-to-agent communication, run concord setup
, then restart existing
client sessions once. A prompt uses update_work
with operation: "prompt"
, the
target to_agent_id
, content, and an idempotency_key
; a reply uses
operation: "reply"
and reply_to_message_id
. A receipt-bearing adapter steers a busy turn or starts an idle turn. Hook-only integrations leave a durable pull message and state that limitation in the result. Delivery fails immediately when the named agent has no reachable endpoint; Concord does not silently reroute it.
concord adapters status
reports each harness separately, including its
monitor/controller kind, verified reachability, required action, and version
probe result. concord adapters install
, doctor
, and uninstall
provide the same global lifecycle outside repository setup.
Concord resolves the repository workspace automatically. Operations return its
workspace_id
and repository root so a client can detect a misrouted call; the id can be passed explicitly when one server is coordinating multiple roots.
Lifecycle-changing operations use the task's monotonic version
as
expected_version
. If two agents act on the same version, only the first
transition succeeds. Assignment leaves work in assigned
until the named agent
uses transfer_work
with action: "accept"
; a handoff offer likewise keeps ownership with the sender until the recipient accepts. Every ownership change is retained in an append-only audit history.
SQLite is the local source of truth, kept in the .concord/
at the root of
the repo the work is happening in. The MCP server resolves that root from
CONCORD_REPO_ROOT
if set, then Claude Code's CLAUDE_PROJECT_DIR
(which Claude
Code sets automatically, even for a user-scoped server), then its working
directory — so every agent in one repo shares one store. Set CONCORD_REPO_ROOT
when running the server somewhere its working directory is not inside the repo.
Linked Git worktrees follow Git's commondir
metadata to the primary checkout, so the main checkout and all linked worktrees intentionally share one Concord database and workspace id.
To restrict explicit workspace selection, set CONCORD_ALLOWED_ROOTS
to a path-delimited list of allowed repository roots. Without an allowlist, decoded roots must still exist and be directories.
concord setup
adds .concord/
to the
repository's .gitignore
, so the generated workspace stays local by default. Teams that want selected artifacts in PRs can remove that rule or force-add the human-readable files:
.concord/
├── concord.db local source of truth
├── HANDOFF.md human-readable handoff
├── REVIEW_PACKET.md review-ready evidence
└── WORK_STATE.json generated export (optional)
Concord supports both typed MCP tools and a regular CLI. MCP-capable agents can
call the tools directly; humans and CLI-oriented agents can work with the same
shared workspace through concord
commands.
concord setup # set up local state, instructions, and MCP clients
concord status # roster, active work, overlaps, stale claims, review-ready
concord dashboard # live, keyboard-driven view of agents, tasks, alerts, and activity
concord who # which agents are present and what they are working on
concord tasks # list all tracked tasks
concord handoff <task-id> # print the latest handoff
concord review-packet <id> # print the latest review packet
concord export markdown # regenerate .concord/ artifacts
concord doctor # workspace checks + per-task tool adoption
concord adapters status # global harness delivery capability matrix
concord --repo ../project status # select by repository path from anywhere
concord --workspace ws_... status # select an id returned by a Concord operation
--repo
and --workspace
are global, mutually exclusive options. The CLI uses
the same CONCORD_REPO_ROOT
→ CLAUDE_PROJECT_DIR
→ working-directory priority and the same linked-worktree canonicalization as MCP.
concord dashboard
is a read-only, full-screen local TUI. It refreshes from the
shared SQLite workspace every second while keeping agents, tasks, alerts,
context, and timeline inside a fixed terminal viewport. Use Tab
to change
panes, j
/k
or the arrow keys to select work, /
to filter, ?
for help,
and q
to quit.
npm install -g @concord-ai/concord-mcp@latest
concord --version
Concord checks daily and surfaces available updates in the CLI, MCP tools, and
dashboard; concord setup
can install one with confirmation, and
CONCORD_NO_UPDATE_CHECK=1
disables checks.
Shared work-state and task memory for coding agents using the same local checkout. Not an orchestrator, code reviewer, hosted sync service, memory vector DB, or autonomous coding agent.
See also: Why not just use markdown?
See CONTRIBUTING.md and
. This repo is strictly typed (no
CLAUDE.md
any
, no typecasts) and modular. Good first issues are labelled .
good first issue
Concord sends product and coordination telemetry to getconcord.ai
. It includes random installation/invocation identifiers; irreversible per-install workspace and task-flow pseudonyms; Concord/Node/platform versions; normalized client metadata; operation names, outcomes, and durations; aggregate overlap/edit-guard results; message delivery stages and latencies; task lifecycle transitions and elapsed time; and explicitly reported acceptance, integration, human-intervention, and rework outcomes.
Concord never sends code, raw file or repository paths, remotes, usernames, raw
task or agent identifiers, message identifiers or content, command arguments,
tool inputs/outputs, or task content. The receiving server stores the request IP
address and derives/stores a country code. Those server-side fields currently
have no automatic expiry. Set CONCORD_TELEMETRY_DISABLED=1
(or
DO_NOT_TRACK=1
) to disable telemetry. Delivery is best effort and can never make a Concord operation fail.