Get Claude Code and Codex talking to each other: a Show HN that scored 9 points, and how it climbed to nearly 1,000 stars over 30 releases
What it is An open source MCP tool that lets coding agents from different vendors, such as Claude Code, Codex and Cursor, talk to each other in the same project, split up work, and avoid editing the same files.
Why it took off Many developers run several agents at once, and they are unaware of each other and step on each other's toes. The big companies only manage their own agents, so the cross-vendor position can only be taken by a third party. The author ships often, adds support for each new agent one by one, and uses Hacktoberfest to hand off the integration work to the community. Each integration adds another searchable entry point.
CHow you could follow Don't build yet another agent-chat tool. Copy the playbook instead: find the gap between big vendors that don't interoperate (for example, syncing rules and memory across agents), ship it with one command, put a working demo on the first screen of the README, and write a "X + Y together" guide for every tool you integrate.
- Data (updated daily) · Repo created 2026-07-14 · 994 stars · 7 days +192
GitHub · stars Data 2026-10-09 → 2026-11-08 (31 days, 16 observations). Points before 10-28 come from deeply / archive backfill, not every day has one
Concord is an open source MCP tool built by an engineer in London, letting Claude Code, Codex, Cursor and other coding agents in the same repo send messages to each other, claim files, and hand off tasks. It was not an overnight hit: the launch post got only 9 points, then over 115 days a release came out nearly every few days, with new agents integrated one by one. October then used Hacktoberfest to hand off the integration work to the community, and stars climbed step by step to 973. This playbook is worth learning. But the "let agents talk to each other" spot is now crowded, and copying it again will struggle to get the same stars.
A Show HN that only got 9 points
On Aug 27, 2026, Alex Choi (alexechoi on GitHub, around 2,500 followers on X) posted a Show HN: "Concord – let Claude Code, Codex and Cursor talk to each other". The post body is just three sentences:
"I've been running more and more agents at once, and I found they know nothing about what the others are doing, even when the work is connected. It's like taking a team's Slack away. Agents repeat work, write conflicting code, and step on each other's toes, simply because they can't talk."
The post ended at 9 points and 4 comments, one of which said "hell yes!!", and another introduced a similar competing solution. The intro post he had made on X the day before got about 6,000 views and 16 likes.
The repo was created in Jul 14, reached 423 stars by Oct 9, and 973 by Nov 6. There was no single day after the HN post when it suddenly took off; the curve is a steepening upward slope.
What it actually does
The README's first screen skips architecture and goes straight to a conversation:
``text 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. ``
When two agents from different vendors went for the same file, Concord told the later one "someone is already editing this," and the two worked out the split between themselves. Below that is a working demo: Claude Code and Codex build a whack-a-mole game together, with one handoff in the middle, and a third agent reviews it at the end.
To use it, run npm install -g and then concord setup in the repo. It registers itself in the config files of Claude, Cursor, Gemini, Grok, and Codex, and writes usage instructions into CLAUDE.md and AGENTS.md. With global mode on, it applies to every repo on the machine. The README lists 10 supported agents: Claude Code, Codex, Cursor, Gemini CLI, Grok Build, Goose, Antigravity, Copilot CLI, Devin CLI, and Conductor. MIT license, the local single-machine version is free. The website also has a cloud version for linking multiple machines, with a team plan at $15/person/month, where agents don't count as seats.
Why this one, and why now
The pain is real, and it's growing. By 2026, lots of developers have Claude Code and Codex open at once, sometimes Cursor too. Reddit's r/ClaudeCode and r/codex keep getting posts like "how do I make Claude Code and Codex talk to each other" and "how do I stop parallel sessions from stepping on each other." The common workaround is copy-pasting between two windows.
It sits where big companies won't. Claude Code 2026 earlier this year shipped Agent Teams built in, zero setup, but it can only coordinate Claude's own sessions. OpenAI and Cursor won't build "let my agent talk to a rival's agent" either. This vendor-neutral position can only be held by a third party.
It ships faster than its peers. From v0.2.0 (7-22) to v0.20.0 (11-05) is about 30 releases. Since October it has shipped a new version every 2 to 5 days, and the author alone has pushed 400+ commits. Many MCP tools ship once and go quiet, so steady updates are a trust signal in themselves.
how the stars piled up
| Period | star | average daily gain |
|---|---|---|
| 7-14 → 10-09 | 0 → 423 | 5 |
| 10-12 → 10-28 | 453 → 738 | 18 |
| 10-28 → 11-02 | 738 → 823 | 17 |
| 11-03 → 11-06 | 861 → 973 | 37 (11-05 in one day +45) |
Figures come from GitHub daily snapshots; there is no data between 10-13 and 10-27.
The October jump lines up with one specific move: the author tagged a batch of issues hacktoberfest, good first issue and help wanted, such as "integrate Qwen Code" and "integrate DeepSeek." Over a dozen outside contributors then submitted PRs and built the OpenCode, Cline, Qwen and Muse Code integrations. Each new agent supported meant another "Concord + [agent]" setup doc, and another searchable entry point. The website follows the same logic with a set of guide pages, such as "Make Claude Code and Codex talk to each other" and "Use Claude Code and Cursor in the same project."
It roughly doubled again in early November, and I couldn't find the cause. There's no matching viral post on X, and npm downloads didn't follow: October averaged about 155 a day, and the first 5 days of November averaged about 139 (npm's official stats). So the extra stars that week likely came from people who saw it and clicked star, not people who installed it (inference). Forks number 56, 5.8% of stars, which doesn't look like inflated numbers.
Where users come from
- The author posting: on X, Show HN, and an "I built an open-source MCP server…" post on Reddit r/mcp. Reach was small; the author's top X post got about 20k views with only single-digit likes.
- Long tail from Reddit Q&A: someone asks on r/ClaudeAI how to stop parallel sessions from colliding, and someone replies recommending Concord (I only saw the search snippet, not the post's score).
- Directories and repost accounts: awesome-mcp-servers, Glama and the MCP Registry all list it. A YouTube channel, "Trending Open Source Projects," ran an episode with about 1,250 views. An X tool-recommendation account reposted it, about 1,900 views. These came after it started gaining traction and were automatic reposts, so they're a result, not a cause.
- Contributors from Hacktoberfest: see the section above. This is the one move I can confirm and the most visibly effective.
- No paid ads found.
Who's competing for this spot
| Project | star | How it differs from Concord |
|---|---|---|
| Claude Code Agent Teams | Built in | Zero install, but only manages Claude's own tools |
| mcp_agent_mail (+ Rust version) | 2,231 + 234 | The first "agent mailbox," feature-heavy, aimed at power users |
| reason-machines/reason-network | 21 days 1,526 | Nearly the same pitch, built on P2P, backed by a company product and big X accounts, gaining users much faster than Concord |
| phodal/routa | 1,836 | A multi-agent platform centered on workspaces and specs, heavier |
| smux / ntm | 1,532 / 462 | Messages between agents at the tmux terminal layer, no claim or handoff |
| foremerge | 462 | Only detects intent conflicts before they happen |
There are also other similar tools with a few hundred stars each, including OpenRig, Ax, ai-maestro and guild, all of which appeared in 2026. Concord wasn't the first, and it doesn't have the most stars. What it leads on is the most supported agents, the easiest setup, and the most frequent updates. That comes from the author's execution, not from the mechanism, which anyone could build. Reason Network, which launched in October, passed it within three weeks, which proves the point.
If it were you
One takeaway: don't build another "let agents talk to each other" tool. This space produced more than a dozen in a year, and a late entrant passed Concord in three weeks. What's worth taking away is the playbook: find a seam where the big vendors' tools don't connect, build a neutral connection layer, and treat your list of supported tools as your growth roadmap.
Who it suits: developers who use several AI tools every day and feel where they fail to connect, and who will ship a new version every few days for months while adding new platforms.
Who it doesn't suit: anyone hoping for a one-shot viral launch (Concord's launch post scored only 9 points; it grew through 115 days and 30 releases), or anyone who only wants to build the Nth copy of an agent-collaboration tool.
How to do it: pick a seam nobody has seriously tackled yet, "cross-vendor" style, such as syncing memory and rules between agents (CLAUDE.md, AGENTS.md and .cursor/rules are three separate, unsynced files), or cross-agent usage and spend tracking (inference, I haven't verified how crowded either is). Put a conversation or a working demo on the first screen of the README, not an architecture diagram. Get install down to one command that writes into each tool's config.
How to get users: for each tool you add, publish a "how X and Y work together" doc or guide page; that's your search entry point. Ship support the day a new tool launches. Answer matching pain-point questions on Reddit. Break integration work into good first issue tickets and hand them to the community in exchange for contributors and stars.
When to move: Hacktoberfest ended in late October, and the next one is October 2027. But new coding agents launch every month, and the window to be "the first to support it" lasts only a few weeks each time.
What would show you misread it: (1) Anthropic, OpenAI or Cursor ships an official cross-vendor collaboration feature, and the neutral position is gone. (2) Concord's npm downloads visibly catch up with its star growth over the next month or two, which would mean the space is still expanding and there's room for late entrants. (3) Reason Network or Concord gets acquired by a big vendor, or clearly stops updating, which would mean this position is worth more elsewhere.
Research notes: competitor table, acquisition evidence, full research report
- Competitors
Name Where Launched Scale How it differs from this one Claude Code Agent Teams Big-company features Around 2026-02 all Claude Code users Native and zero install, but only coordinates Claude's own sessions. Concord works across Claude, Codex, Cursor and other tools. mcp_agent_mail / mcp_agent_mail_rust Open source About 2025-10 2,231 + 234 star The earliest agent-mailbox MCP. Heavier, aimed at VPS and tmux users. Concord has one-command setup, real-time delivery, and claim-based collision prevention, plus a cloud team edition. Reason Network (reason-machines) Open source About 2026-10-16 1,526 stars (21 days), +211 in 7 days Same pitch, built on P2P (iroh), backed by a Reason product and big X accounts, so it's gaining users faster. Concord is MCP-native, supports more harnesses, and already has published team pricing. phodal/routa Open source About 2026-02 1,836 star A multi-agent platform centered on workspaces and specs, heavier. smux / ntm Open source 2026 H1 1,532 / 462 star Messages between agents at the tmux terminal layer, with no claim or handoff at the MCP semantic layer. foremerge Open source About 2026-08 462 star Only detects intent conflicts, doesn't do messaging. - Where users come from
- Verified Founder's own posts on X / HN / Reddit: the launch post by X @AlexChhk 2026-08-26 got about 6k views. Show HN scored 9 points. An r/mcp "I built…" post and an r/aiagents story post, "My friend gave Claude Code and Codex…"
- Verified Hacktoberfest / good first issue community work: in October many issues were tagged hacktoberfest, help wanted and good first issue. Outside contributors submitted PRs for OpenCode, Cline, Qwen, Muse Code and other integrations. Average daily star growth rose from about 5 to about 18 over the same period.
- Verified Continuous addition of new harnesses + SEO guide pages on the website: supports 10+ agents, and the site has pages such as guides/claude-code-cursor-same-project.
- Inference Long tail from Reddit pain-point threads: in discussions on r/ClaudeAI and r/ClaudeWorkflows about collisions between multiple agents, someone mentioned Concord (search snippet).
- Verified Repost accounts / directories: the YouTube "Trending Open Source Projects" channel with about 1,250 views, a recommendation post by @DanKornas, and listings on awesome-mcp-servers, Glama and the MCP Registry.
- Inference Paid promotion: none found.
Concord MCP (Get-Concord-AI/concord-mcp): why it took off
Research date 2026-11-06. Channel: GitHub. The conclusion first: this is a slow-burn library built through the founder's sustained releases and open-source community work, not a breakout hit. Its star curve accelerates linearly, and no single launch drove it. It hits a real pain point: several agents open in the same repo (Claude Code, Codex, Cursor) don't know what each other is doing. It bets on the cross-vendor position, which the native Claude Code Agent Teams can't cover because it only manages Claude's own sessions. Commercially it's open-core, with Concord Cloud, and the team edition is $15/person/month. So far it's circulating in small circles; neither HN nor X has driven much traffic.
1. What it is
- A local-first MCP server plus CLI (npm
@concord-ai/concord-mcp, MIT license) that lets coding agents like Claude Code, Codex, Cursor, Gemini CLI, Grok Build, Goose, Antigravity, Copilot CLI, Devin CLI and Conductor discover each other, send messages in real time, claim files and tasks, detect collisions before editing, and hand off tasks with evidence. Source: README - Install:
concord setupin one command writes the MCP registration into each client's config (.mcp.json,.cursor/mcp.json,~/.codex/config.toml, etc.) and writes usage instructions into CLAUDE.md / AGENTS.md. There's also a "global mode" that applies to every repo on the machine. - Monetization (getconcord.ai/pricing): the open-source single-machine version is $0. Cloud's free tier is currently early access and supports multiple machines plus a dashboard, with Claude and ChatGPT apps. The team tier is $15/person/month, agents don't count as seats, and it includes member management, "which agent can direct which," and an admin message view. The site's pitch has shifted from "individual engineer" to "team": "Agents made each of you faster. Not the team."
- Team: the main author is alexechoi (Alex Choi, London, X @AlexChhk with about 2.5k followers, describes himself as Founding Engineer), with 417 commits. Everyone else has made occasional contributions. Tracxn (2026-08-24) lists it as not yet funded. The website is hiring a remote junior full-stack developer. Sources: GitHub contributors API, Tracxn
2. Growth data
| Date | star | Notes |
|---|---|---|
| 2026-07-14 | 0 | Repo created |
| 2026-10-09 | 423 | first 87 days averaged about 4.9 a day |
| 2026-10-12 → 10-28 | 453 → 738 | 16 days +285, about 18 per day |
| 2026-10-28 → 11-02 | 738 → 823 | about 17 per day on average |
| 2026-11-03 → 11-06 | 861 → 973 | averaged about 37 a day (11-05 single-day +45) |
Source: our github repo_day table (10-09~10-12 from deeply history, daily snapshots from 10-28 on); see data card.
- npm downloads (api.npmjs.org): July 2,088, August 2,713, September 960, October 4,795, November 1–5 day 695 (daily average about 139, close to October's daily average of about 155). GitHub stars doubled in November, but npm downloads didn't follow. So the recent star surge looks more like more people noticing it than more people installing it. There is also a curl one-line install script, which isn't counted in npm; not verified.
- Very frequent releases: from v0.2.0 (7-22) to v0.20.0 (11-05), about 30 releases in total, and after October nearly one every 2–5 days. Source: GitHub releases.
- 56 forks, 29 open issues, and 12 external PRs waiting in the queue. Forks/stars are about 5.8%, which doesn't look inflated. That ratio is low for a new repo, but normal for a tool-style CLI.
3. Competitors
| Product | Form | Launched | Scale | How it differs from Concord |
|---|---|---|---|---|
| Claude Code Agent Teams | Big-company features | Around 2026-02 | all Claude Code users | Native, zero install, but it can only coordinate Claude's own sessions; Concord sells cross-harness coordination (Claude↔Codex↔Cursor…). |
| Dicklesworthstone/mcp_agent_mail (Python, deprecated) + mcp_agent_mail_rust | Open source | About 2025-10 | 2,231 + 234 stars; the author's repos total 31k stars | The earliest MCP for an "agent mailbox", with Git archiving and 45 tools, aimed at VPS / tmux power users. Concord takes a lighter route: one command installs into all clients, real-time delivery, claim-based collision prevention, plus a cloud and team edition. |
| reason-machines/reason-network | Open source + company product | About 2026-10-16 | 21 days, 1,526 stars; +211 over 7 days, cooling off | Same pitch (coding agents on a team talk to each other), P2P (iroh), backed by the Reason product and an X account with a big following (@RoundtableSpace). It gained traction much faster than Concord and is the most direct rival. |
| phodal/routa | Open source | About 2026-02 | 1,836 star | A heavier multi-agent collaboration platform centered on workspaces and specs. |
| ShawnPana/smux, Dicklesworthstone/ntm | Open source | 2026 H1 | 1,532 / 462 star | Terminal-layer agent messaging built on tmux, not MCP semantics, and no claims or handoffs. |
| naw103/foremerge | Open source | About 2026-08 | 462 star | A coordination protocol that catches intent conflicts before code conflicts, focused only on collision prevention. |
| mathomhaus/guild, Cotal, ai-maestro, etc. | Open source | 2026 | 300–850 star | Shared memory and task coordination; commoditized. |
| Ax(HN Show) | Open source | 2026 | HN post | Locally lets Claude / Codex / OpenCode message each other, nearly the same product. |
Sources: GitHub repo search and repo profiles; Claude Code docs: agent teams; reasonmachines.com/network; HN Ax.
Verdict: the space is crowded and still expanding (Reason Network surfaced again in October). Concord isn't the first to build this, nor does it have the most stars. Where it leads: the most harnesses supported, the easiest install, and the most frequent iteration. It's also one of the few that has publicly priced a team edition.
4. Where users come from (acquisition)
- The founder posted himself, but reach was small
- X: 2026-08-26 Alex Choi posted about Concord, ❤16, roughly 6k views; 10-13 piggybacked on the Cloudflare MCP incident, roughly 20k views, ❤7. Source: X live search (TikHub).
- HN: 2026-08-27 Show HN, only 9 points and 4 comments, didn't take off.
- Reddit: an r/mcp post titled "I built an open-source MCP server that lets Claude Code, Codex and Cursor…", and an r/aiagents post titled "My friend gave Claude Code and Codex agents a way to talk to each other… they reinvented bureaucracy". The latter tells the story in a "my friend built this" voice to drive traffic. Reddit blocked scraping so scores weren't captured; not verified.
- Long-tail replies in Reddit pain-point threads (SEO / community): r/ClaudeAI's "How do you keep parallel Claude Code sessions from stepping on…" and r/ClaudeWorkflows' Concord workflow post both surface Concord as a recommendation. Questions like "how to use Claude Code and Codex together" keep recurring on r/codex and r/ClaudeAI, so the demand is persistent. Source: Jina search result summaries.
- Aggregator and reposter amplification: a YouTube channel "Trending Open Source Projects" video (about 1,250 views, about 2 weeks ago), one YouTube Short, one Instagram reel, an X tool-recommendation post by @DanKornas (10-10, about 1.9k views), and a Show HN reposted on techbytes.app. These were auto-reposted after GitHub traction picked up, so they're a result, not a cause.
- Hacktoberfest and good-first-issue operations (confirmed): in October the author tagged many issues with
hacktoberfest,help wanted, andgood first issue(e.g. "add Qwen Code integration", "add DeepSeek integration", "mark decisions as superseded"). A batch of outside contributors then submitted PRs building integrations for OpenCode, Cline, Qwen, Muse Code and others. The contributor list includes bconnnnn, oseniabdulhaleem, Darshan3690, akramcodez, jseramn and a dozen more. Each new harness integration adds another searchable entry point. October's star rate rose from 5 per day to 18 per day, which matches the timing. Source: GitHub issues API. - Directories and registries: awesome-mcp-servers, Glama, the MCP Registry, and Skills Directory all list it. Source: Jina search.
- The source of the early November acceleration is unclear: starting on 11-03, stars rose 34–45 per day, but neither the X local library nor live search turned up a matching big-account post, and npm downloads didn't rise either. Possibly Reddit or YouTube long tail, or in-GitHub recommendations; not verified.
- No evidence of paid promotion was found.
5. Why it took off
- The pain point is real and growing: by 2026 many developers run Claude Code and Codex at the same time (some add Cursor too), and "I copy-paste plans between two agents myself" is a frequent complaint on Reddit (e.g. r/ClaudeCode's "Did anyone build a model where claude code and codex can talk…").
- Owning the cross-vendor position: big-vendor native collaboration (Claude Code Agent Teams) only covers its own tools, and OpenAI or Cursor won't build a way for my agent to talk to a rival's agent. A neutral third party has structural room here. The README's first line is "Let Claude Code, Codex, Cursor… talk to each other".
- Coverage as the growth engine: each additional supported harness (Grok Build, Antigravity, Copilot CLI, Devin, Conductor, Muse Code…) brings a batch of search traffic and another docs page or guide (the website has SEO guide pages like "Use Claude Code and Cursor on the same project"). New harnesses get integrated as soon as they launch, and Hacktoberfest outsources the integration work to the community.
- One command to install, with a demo:
concord setupautomatically rewrites all client configs. The first screen of the README shows a script of Claude and Codex fighting over the same file and negotiating a division of work, plus a runnable whack-a-mole demo. The concept clicks at a glance. - Trust from frequent releases: about 30 releases in 115 days, the author has committed 400 times recently, and issues get timely replies. That sets it apart from many similar MCP projects that get abandoned after release.
6. Differentiation
- Versus native Agent Teams: cross-harness is the core difference and the reason it exists.
- Versus mcp_agent_mail and tmux-style tools: lighter and more productized (one-click setup, global mode, real-time delivery receipts, claim/overlap detection), plus a cloud multi-machine option and a team edition.
- Versus Reason Network: the difference is small. Reason is P2P, backed by its own agent product, and it gained traction faster. Concord's edge is native MCP support, more supported harnesses, and public pricing.
- Judgment: the differentiation (cross-harness plus coverage) is what made it run, but the moat is shallow. Anyone can build the mechanism, and competitors are already following. Its speed comes from the founder's execution (release cadence, number of integrations), not from a technical barrier.
7. Visibility
- Still spreading in small circles: HN 9 points; the founder's best X post got about 20k views with single-digit to low-teens likes; no media coverage and no big-name endorsements; revenue not disclosed; Tracxn shows no funding.
- Not really copycats, more like a simultaneous wave: Reason Network (October), Ax, foremerge and others were all building "agents talking to each other" in the same window. Some launched later but gained traction faster.
8. What to borrow
- Filling the gap where big vendors don't interoperate, a neutral connection layer that the big players won't build themselves.
- Growth by adding an entry point for each new platform: the supported-harness list is the growth checklist, paired with docs/guides pages for SEO.
- Outsourcing integration work to the community via Hacktoberfest and good-first-issue, earning contributors and stars at the same time.
- Open-core pricing charged per seat, with agents not counted as seats, and an explicit "team" narrative.
9. Uncertain
- The specific source of the early-November star acceleration wasn't found; npm didn't follow, so real usage growth is questionable.
- Reddit post scores and dates couldn't be retrieved (blocked).
- Whether Concord Cloud or the team edition has paying users is unknown.
- The stargazer time distribution wasn't obtained (the GitHub API rejected our token), so each channel couldn't be aligned week by week.