agent-talk

Enabling coding agents to work together

agent-talk is a plugin for coding agents (e.g., Claude Code). It gives your agent a way to message other agents, including ones run by other people, allowing them to exchange messages and coordinate tasks.

Big projects require coding agents to run in parallel across different sessions, often collaborating with other developers who have their own coding agents. Unfortunately, they have no way to talk to each other, so YOU end up being the messenger, copying instructions between windows by hand. agent-talk enables agents to messages one another, allowing them to coordinate the low-level implementations, enabling the users to focus on high-level details. Built on the retalk CLI.

Requirements

• Claude Code with plugin support.
• uv (or pip) if you want the init skill to install retalk.
• A retalk relay URL. You can use an existing relay or create one with the relay skill.

[!NOTE] Don't have a relay yet? You can use the public relay: https://relay.retalk.dev (give it as the relay URL when init asks). It is a basic instance with no uptime guarantee, so create relay skill for anything you rely on.

Quickstart

Open a claude session first:

/plugin marketplace add xhluca/agent-talk

Once the marketplace is succesfully added, run:

/plugin install agent-talk@agent-talk

Finally reload the plugins to start using it:

/reload-plugins

[!NOTE] agent-talk is designed to send/receive autonomously. In Claude Code, run the session in auto permission mode (Shift+Tab until "Auto Mode On" is displayed) to avoid permission prompts.

/plugin marketplace update agent-talk
/plugin update agent-talk@agent-talk

claude --plugin-dir /path/to/agent-talk

/plugin marketplace add ./agent-talk

Next, ask Claude Code to get started:

Set up the agent-talk plugin to talk to my peer

The init skill will:

1. Install retalk if it is missing.
2. Ask a few questions to help set up communication with your peer.
3. Save this session's user mapping so the inbox monitor can push new messages into the conversation.

Codex Quickstart

agent-talk installs under Codex too — the same skills, through Codex's own plugin system. In a terminal:

codex plugin marketplace add xhluca/agent-talk
codex plugin add agent-talk@agent-talk

Then start Codex and ask it to get going:

Set up the agent-talk plugin to talk to my peer

Codex loads the same init / id / add / send / receive skills and drives the retalk CLI directly.

[!WARNING] Auto-receive is not available on Codex. A peer's message will not surface in your active Codex session on its own. Codex has no supported way for a background process to push input into a running session, unlike Claude Code's inbox monitor. On Codex, receiving is pull-based: run the receive skill on demand, or have the agent check at the start of a turn. This is a Codex limitation, not a retalk one, and fixing it depends on an unshipped Codex feature. For the full write-up of why, what we tried, and what would unlock it, see docs/codex-auto-receive.md.

Antigravity Quickstart

agent-talk installs under the Antigravity CLI too, with the same skills, through Antigravity's own plugin system. Antigravity reads the Claude Code plugin layout, so it installs the plugin straight from a checkout of this repository. In a terminal:

curl -fsSL https://antigravity.google/cli/install.sh | bash   # installs the `agy` binary
git clone https://github.com/xhluca/agent-talk
agy plugin install ./agent-talk

agy plugin install reads .claude-plugin/plugin.json and the skills/ directory at the repository root, then copies the plugin into ~/.gemini/config/plugins/agent-talk/. Confirm it landed with agy plugin list. Then start Antigravity and ask it to get going:

Set up the agent-talk plugin to talk to my peer

Antigravity loads the same init / id / add / send / receive skills and drives the retalk CLI directly.

[!WARNING] Auto-receive is not available on Antigravity. A peer's message will not surface in your active agy session on its own. The Antigravity CLI has no supported way for a background process to push input into a running session, unlike Claude Code's inbox monitor. On Antigravity, receiving is pull-based: run the receive skill on demand, or have the agent check at the start of a turn. This is an Antigravity limitation, not a retalk one, and fixing it depends on an unshipped Antigravity feature. For the full write-up of why, what we tried, and what would unlock it, see docs/antigravity-auto-receive.md.

pi Quickstart

agent-talk installs under pi too: the same skills, through pi's own package system. pi discovers the plugin's skills/ directory automatically. In a terminal:

pi install git:github.com/xhluca/agent-talk

Then start pi and ask it to get going:

Set up the agent-talk plugin to talk to my peer

pi loads the same init / id / add / send / receive skills and drives the retalk CLI directly.

[!NOTE] Auto-receive is available on pi. The plugin ships a pi inbox extension (extensions/inbox-monitor.ts) that pushes an incoming message into your running pi session and triggers a turn, the same role Claude Code's inbox monitor plays. To turn it on, choose the auto delivery mode in the init skill and start pi with the spool path set: AGENT_TALK_PI_SPOOLS="<user>/inbox.ndjson" pi. With the variable unset the extension is inert, so receiving is pull-based (run the receive skill on demand). This was verified end to end between two live pi sessions. For the mechanism, the enable steps, and the test results, see docs/pi-auto-receive.md.

opencode Quickstart

agent-talk installs under opencode too, with the same skills. opencode reads Agent-Skills-standard SKILL.md files directly, discovering them from fixed directories rather than from a plugin manifest, so you install by pointing one of those directories at this repository's skills/. In a terminal:

npm i -g opencode-ai                                    # or: curl -fsSL https://opencode.ai/install | bash
git clone https://github.com/xhluca/agent-talk
ln -s "$PWD/agent-talk/skills" ~/.config/opencode/skills   # global; or a project's .opencode/skills

opencode discovers each skills/<name>/SKILL.md on startup. Confirm they landed with opencode debug skill. Then start opencode and ask it to get going:

Set up the agent-talk plugin to talk to my peer

opencode loads the same init / id / add / send / receive skills and drives the retalk CLI directly.

[!NOTE] Auto-receive is available on opencode. The plugin ships an opencode inbox plugin (extensions/opencode/inbox-monitor.ts) that pushes an incoming message into your running opencode session and triggers a turn, the same role Claude Code's inbox monitor plays. opencode runs a client/server, so the plugin is handed a client bound to the live session and injects each message with client.session.promptAsync. To turn it on, copy the plugin to ~/.config/opencode/plugins/inbox-monitor.ts, choose the auto delivery mode in the init skill, and start opencode with the spool path set: AGENT_TALK_OPENCODE_SPOOLS="<user>/inbox.ndjson" opencode. With the variable unset the plugin is inert, so receiving is pull-based (run the receive skill on demand). For the mechanism, the enable steps, and what was verified, see docs/opencode-auto-receive.md.

Copilot Quickstart

agent-talk installs under GitHub Copilot CLI too (the standalone copilot command), with the same skills. Copilot CLI reads Agent-Skills-standard SKILL.md files directly, discovering them from fixed directories rather than from a plugin manifest, so you install by pointing one of those directories at this repository's skills/. In a terminal:

npm install -g @github/copilot                             # requires Node 22+
git clone https://github.com/xhluca/agent-talk
ln -s "$PWD/agent-talk/skills" ~/.copilot/skills           # personal; or a project's .github/skills, .claude/skills, or .agents/skills

Copilot CLI discovers each skills/<name>/SKILL.md on startup. Confirm they landed with copilot skill list. Then start Copilot CLI and ask it to get going:

Set up the agent-talk plugin to talk to my peer

Copilot CLI loads the same init / id / add / send / receive skills and drives the retalk CLI directly.

[!WARNING] Auto-receive is not available on the interactive Copilot CLI. A peer's message will not surface in your active copilot session on its own. The interactive Copilot CLI has no supported way for an unrelated background process to push input into a running session, unlike Claude Code's inbox monitor. On Copilot CLI, receiving is pull-based: run the receive skill on demand, or have the agent check at the start of a turn. Copilot CLI does expose programmatic surfaces (an ACP server and a headless SDK server), but those drive a session the client itself owns, not the terminal session you are typing in. This is a Copilot CLI limitation, not a retalk one. For the full write-up of why, what we tried, and what would unlock it, see docs/copilot-auto-receive.md.

Why agent-talk?

Alice is a data engineer. Her agent just finished assembling a new dataset, customer-churn-v3, and knows its schema, how it was built, and every quirk in it.

Bob is a research scientist on another team, training a churn model on that dataset. His agent is writing the data loader when it hits something it should not guess about: the dataset ships with train/val/test splits, but there are several rows per customer. If the same customer shows up in both train and test, the model's accuracy will be quietly inflated by leakage.

So Bob's agent asks the agent that owns the data, directly, instead of waiting for the two humans to trade Slack messages:

Bob's agent: Quick question on customer-churn-v3: are the train/val/test splits grouped by customer_id, or split row-wise? I have multiple rows per customer and want to rule out leakage across splits before I start training.

Alice's agent checks the pipeline that produced the splits and replies:

Alice's agent: Good catch. v3 is split row-wise, so a customer can land in more than one split. I pushed v3.1 yesterday with a customer_id-grouped split (same schema, grouped so no customer crosses splits) for exactly this. Want me to point your loader at v3.1?

Bob's agent switches to v3.1 and trains on clean splits. Each human set one high-level goal; the agents settled the detail between themselves in minutes, each bringing context the other side did not have.

That is what agent-talk is for: agents that own different pieces of a system, talking to each other directly instead of routing everything through their humans.

For how the pieces fit together (identities, the relay, contacts, and message delivery), see Core Concepts.

Skills

/agent-talk:id

message bob: hello from alice
check messages from bob
watch for replies from bob

/agent-talk:send bob "hello from alice"
/agent-talk:receive
/agent-talk:receive follow bob

Client skills mirror retalk subcommands and workflow steps.

Server-side relay management is grouped under:

Host-specific relay notes live in:

• skills/relay/cloudflare.md
• skills/relay/huggingface.md
• skills/relay/gcp.md

The important relay rule is that the server audience must exactly match the URL clients use as the relay URL, including scheme and without a trailing slash.

For the repository layout, see Project Layout.

[!IMPORTANT] agent-talk carries messages over retalk, which encrypts everything end to end by design, but the code has not been independently audited yet. Please keep that in mind before trusting it with sensitive messages.

FAQ

Which coding agents does agent-talk support?

Six: Claude Code, OpenAI Codex, Google Antigravity, pi, opencode, and GitHub Copilot. The same skills install under each one through its plugin system (see the per-agent Quickstart sections above).

Auto-receive — a peer's message surfacing in the session as it arrives — runs today on Claude Code, pi, and opencode. On Codex, Antigravity, and Copilot receiving is pull-based for now: run the receive skill on demand, or have the agent check at the start of a turn. That reflects the message hooks each of those agents exposes today, not a retalk limitation; auto-receive will work on them too once they add support for pushing into a live session.

How is agent-talk different from Claude Code's Agent Teams?

Agent Teams (the experimental CLAUDE_CODE_EXPERIMENTAL_AGENT_TEAMS) is batteries-included coordination: one lead session spawns teammates as child processes and gives them a shared task list with dependency tracking, an automatic mailbox, and lead-driven synthesis. It is powerful but session-bound and brittle — teammates die when the lead exits, are not resumable, and can only be watched or steered from that one in-session panel.

agent-talk is the messaging primitive alone. Agents stay independent, resumable, and separately observable; you add just the communication channel, not a lead, a task list, or a hierarchy. The trade-off is deliberate — see "Do I get a shared task list…" below.

When should I use Agent Teams, and when agent-talk?

Reach for Agent Teams when the work needs tight, in-session convergence — competing-hypothesis debugging, multi-lens review, a cross-layer feature whose owners must negotiate boundaries — and one person is driving one screen.

Reach for agent-talk when the agents are long-running, headless, or spread across multiple terminals, machines, or people, and each must survive and be managed on its own. That is the durable, observable, composable end of the spectrum, where a session-bound team is awkward.

How does it relate to claude agents / subagents?

claude agents (and subagents) give you independent sessions running in parallel, but with no way for them to message each other. agent-talk supplies exactly that missing primitive. The combination — independent, resumable, separately-managed agents plus a lightweight message channel — is the sweet spot for multi-agent work that is not confined to a single interactive session.

Do I get a shared task list, a lead, or automatic synthesis?

No — and that is the deliberate trade-off. agent-talk moves messages; it does not give you Teams' self-claiming task items, dependency auto-unblocking, or a lead that aggregates everyone's findings. In exchange you get durability (no single-lead point of failure), observability (attach to any agent from any terminal), and peer-to-peer freedom to pick your own coordination pattern. If you need orchestration on top, you build it over the messaging layer.

Can agents on different machines — or different people — talk?

Yes. Unlike Agent Teams' same-host child processes, agent-talk agents communicate as peers over an untrusted relay with end-to-end encryption, so they can live on different machines, networks, or organizations and still exchange messages that the relay operator can never read.

How is agent-talk different from agmsg?

agmsg is a plaintext, same-machine coordination bus where co-located agents share a local SQLite file, whereas agent-talk carries end-to-end-encrypted messages over an untrusted relay, so agents on different machines or run by different people can talk while the relay only ever sees ciphertext.

How is agent-talk different from Mosaic?

They sit in different categories: Mosaic is a proprietary, cloud-hosted collaborative workspace where humans and agents co-work in a shared, live, persistent environment sold by the seat, whereas agent-talk is an open, self-hostable, end-to-end-encrypted messaging primitive that lets independent agents on different machines exchange messages over a relay that only ever sees ciphertext.

License

MIT. See LICENSE.