Editor (ACP)

cetas-acp serves Cetas over the Agent Client Protocol on stdio. Any ACP client can launch it, so the same agent you know from the terminal shows up inside your editor with its own permission UI.

Before you connect

The editor host reads the same home directory as every other surface, and it refuses to start without a provider — an agent with no model cannot serve a prompt. So configure once, in the terminal:

/login
/model

Then get the binary: extract cetas-acp from a release archive, or build it from a checkout.

Zed

Add a top-level agent_servers entry to Zed’s settings:

{
  "agent_servers": {
    "Cetas": {
      "type": "custom",
      "command": "/absolute/path/to/cetas-acp",
      "args": [],
      "env": {}
    }
  }
}

Use cetas-acp.exe on Windows. If your Zed version expects a different schema, follow Zed’s custom agent instructions.

Then open the agent panel and pick Cetas. Zed identifies itself during initialize, so this session’s transcript files under <CETAS_HOME>/.cetas/sessions/zed/.

Lody

Lody treats external agents as an Agent Config with a launch command. Register Cetas once:

1. Open Settings → Agent Config and add a config.
2. Name it Cetas.
3. Set CLI Type to Custom ACP.
4. Put the absolute path in Launch command — /absolute/path/to/cetas-acp.
5. Add environment variables you need in the same Agent Config (see below).
6. Click Test. Lody launches the agent and reads its capabilities and model list; a provider must already be configured or this step fails.
7. Save, then pick the config when you start a conversation.

Lody parses the launch command into a command plus arguments — quotes are supported, but pipes, redirects, globs, and $VARS are not evaluated. Put environment variables in the Agent Config instead of the command.

Lody sessions land in <CETAS_HOME>/.cetas/sessions/lody/.

What each session gets

Every ACP session gets its own agent and its own mutable machinery — model router, permission policy, MCP bridge, transcript store, in-flight turn — so prompts on different sessions run concurrently without cross-wiring approvals. Provider settings and model catalogs are assembled once and shared read-only.

The client owns the chat record: it stores the conversation and the session id, and hands the id back on session/resume. Cetas persists the committed transcript to disk so a restart resumes from there rather than from memory.

Session configuration

ACP advertises config options for:

• model — a successful change is persisted as the next launch’s selection.
• effort — persisted when the active model exposes reasoning-effort choices.
• permission — runtime-only and session-scoped; deliberately not persisted.

Changes arrive through session/set_config_option. For connection failures, read the editor’s ACP log first, then the agent’s stderr — all diagnostics go there, because stdout carries JSON-RPC frames only.

Environment

MCP setup is covered in MCP; the full variable reference is in Environment Variables.