All comparisons
Agent messaging bus
Concord vs Agent Relay
Agent Relay gets agents talking. Concord gets them talking and stops them editing the same files while they do.
Concord
- Yes14
- Partly0
- Not in their docs0
Agent Relay
- Yes7
- Partly1
- Not in their docs6
Across 14 capabilities, from public docs as of October 2026.
at a glance
Two tools, side by side.
| Attribute | Concord | Agent Relay |
|---|---|---|
| What it is | Shared work-state and messaging for coding agents (MCP server + CLI) | Messaging infrastructure for coding agents: channels, DMs, threads, flows |
| Works with | Claude Code, Codex, Cursor, Gemini CLI, Copilot CLI, Grok Build, Goose, Antigravity, Devin CLI, any MCP client | Claude Code, Codex, OpenCode, Grok CLI, Devin and others |
| Runs | Inside the agents you already use. Local SQLite, or Cloud across machines | Its own local server or hosted cloud |
| License | MIT | Apache-2.0 |
| Price | Free locally. Cloud free for one person. Team $15/seat, agents free | No public pricing |
feature by feature
Concord 14 of 14. Agent Relay 7.
| Capability | Concord | Agent Relay |
|---|---|---|
| Works with the agents you already run | Yes9 harnesses + any MCP client | Yes |
| Native MCP server | Yes | Yes36 chat and spawn tools |
| Claim files before editing | Yes | Not in their docs |
| Overlap warning before an edit | Yes | Not in their docsresolves conflicts after |
| Block edits to claimed files in hooks or CI | Yesconcord check | Not in their docs |
| Replyable prompts between different vendors' agents | Yeslive where the harness allows | Yeschannels and DMs |
| Task memory: decisions, assumptions, findings | Yes | Partlysearchable history |
| Accepted handoffs with an audit trail | Yesversioned, append-only | Not in their docsno ownership transfer |
| Review packet: tests, risks, provenance | Yes | Not in their docs |
| Flags work a dead session left claimed | Yes | Not in their docs |
| Agents on different machines | YesConcord Cloud | Yes |
| Open source | YesMIT | YesApache-2.0 |
| Runs locally with no account | Yes | Yes |
| Keep your terminal and IDE, no new app | Yes | Yes |
From Agent Relay's public docs as of October 2026.YesPartlyNot in their docs
in their code
We read AgentWorkforce/relay.
| Question | concord-mcp | AgentWorkforce/relay |
|---|---|---|
| Who owns a file | YesVersioned claims on files and tasks | None. Agents coordinate by chat |
| Two agents, one file | YesOverlap warning before the edit. concord check can block it | Nothing checks it |
| Handing work over | YesReceiver accepts or declines. Append-only audit history | No ownership transfer |
| What gets remembered | YesTyped decisions, assumptions and findings on each task | Message history and search |
| MCP tools shipped | Yes5 coordination tools, for any MCP client | 36 tools, all chat and agent spawning |
Read from both repositories in October 2026. concord-mcp: 781 test cases, 28 test files on claims alone. Latest release v0.18.0.
from their issue tracker
- #1587Open: concurrent relay teams in one checkout cross workersHow Concord handles it
- #1321Open: agent output lost if the broker crashesHow Concord handles it
why teams pick concord
If you only need a chat line between agents, a relay works. If those agents share a repository, you need the claims, memory and handoffs Concord adds on top of messaging.
- 01
Claims before chat
A message after a collision is a cleanup. Concord flags the overlap before the second agent writes.
Prevent conflicts - 02
Structured, not scrollback
Decisions and assumptions are typed and attached to the task, not buried in a channel.
Persist decisions - 03
Handoffs that land
Ownership moves only when the receiver accepts, and the review packet carries tests and risks.
Hand off work
common questions
- Is Concord an Agent Relay alternative?
- Yes. Concord sends replyable prompts between agents in different harnesses, and adds file claims, overlap detection, task memory and review evidence through one MCP server.
- Does Concord need a channel or chat app?
- No. Agents message each other through MCP tools inside the harness they already run. Humans read the same state with concord status or the Cloud dashboard.
- Can Concord stop a merge conflict instead of resolving it?
- Yes. Agents claim files with start_work before editing, the second agent gets an overlap warning, and concord check can block the edit in a hook or CI.
keep reading
Switching from Agent Relay? Start free.
or stay local: concord-mcp on GitHub