---
title: "Editor (ACP)"
description: "Drive the same Cetas agent from an Agent Client Protocol editor — Zed and Lody walkthroughs."
---

> Documentation Index
> Fetch the complete documentation index at: https://colmugx.github.io/cetas/llms.txt
> Use this file to discover all available pages before exploring further.

# Editor (ACP)

`cetas-acp` serves Cetas over the [Agent Client Protocol](https://agentclientprotocol.com/)
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:

```text
/login
/model
```

Then get the binary: extract `cetas-acp` from a
[release archive](/cetas/en/getting-started/installation/), or build it from a checkout.

## Zed

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

```json
{
  "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](https://zed.dev/docs/ai/external-agents#custom-agents).

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

| Variable | Effect |
| --- | --- |
| `CETAS_HOME` | Overrides the platform home; state lands in `<CETAS_HOME>/.cetas` |
| `CETAS_PERMISSION_MODE` | Startup posture: `readonly`, `workspace_write`, `interactive`, `auto`, `yolo`. Unset means `yolo`; an unrecognized value warns once and falls back to `workspace_write` |
| `CETAS_MCP_MODE=eager` | Connect configured MCP servers at startup instead of on the first turn |
| `CETAS_DELEGATE_FS=host` | Route file reads and writes through the editor's `fs/*` reverse calls instead of the local filesystem |
| `CETAS_DEBUG_WIRE=1` | Append the session's wire traffic to `<CETAS_HOME>/.cetas/debug/<session-id>-wire.jsonl` |
| `CETAS_DEBUG_MCP_CATALOG=1` | Dump the session's tool catalog to `<CETAS_HOME>/.cetas/debug/<session-id>-catalog.json` |

MCP setup is covered in [MCP](/cetas/en/configuration/mcp/); the full variable reference
is in [Environment Variables](/cetas/en/reference/environment-variables/).

Source: https://colmugx.github.io/cetas/en/editor/index.mdx