feat: add ACP adapter for local and remote agents

.changeset/bright-apes-serve-acp.md

@@ -0,0 +1,5 @@
+---
+"eve": patch
+---
+
+Launch local or deployed eve applications as stable ACP v1 agents with `eve acp [url]`, including streamed messages, tool activity, human input, cancellation, and concurrent sessions.

docs/guides/acp.md

@@ -0,0 +1,88 @@
+---
+title: "Use eve through ACP"
+description: "Launch a local eve agent from Zed and other Agent Client Protocol clients."
+---
+
+Agent Client Protocol (ACP) clients can launch an authored eve application as a local subprocess. eve serves stable ACP v1 over stdio while its normal development server remains the execution runtime.
+
+```sh
+eve acp
+```
+
+Without a URL, the client starts one process from the eve application root. It supervises a local development server, and closing the ACP connection stops that owned server. To bridge ACP to a deployed eve agent, pass its URL:
+
+```sh
+eve acp https://agent.example.com
+```
+
+## Configure Zed
+
+Open the eve application root as the Zed workspace. In **Agent Settings → External Agents**, add a custom agent:
+
+```json
+{
+  "agent_servers": {
+    "eve-local": {
+      "type": "custom",
+      "command": "pnpm",
+      "args": ["exec", "eve", "acp"],
+      "env": {}
+    }
+  }
+}
+```
+
+Use an absolute command path if Zed cannot find `pnpm` in its environment. The workspace must be the same directory as the eve application root; eve rejects a different `session/new.cwd` instead of running the wrong application.
+
+Disable Zed project MCP servers for this agent. The initial eve adapter does not accept client-provided MCP servers.
+
+## Supported behavior
+
+ACP clients receive:
+
+- streamed assistant text and reasoning;
+- tool-call requests and results;
+- one-time tool approval and denial requests;
+- fixed-choice and freeform questions when the client supports ACP form elicitation;
+- cooperative turn cancellation;
+- independent concurrent ACP sessions;
+- session closure and process cleanup.
+
+Development rebuilds retain normal eve semantics. In-flight work stays pinned to its generation, and the next turn uses the newest successful generation.
+
+## Security and capability limits
+
+ACP mode does not give the agent access to the editor's host filesystem or terminal. `session/new.cwd` identifies the eve application being launched; it is not mounted into the agent sandbox.
+
+The initial adapter does not support:
+
+- a deployed ACP HTTP or WebSocket endpoint;\n- ACP authentication (remote bridges use the deployed eve agent's existing HTTP authentication);
+- ACP v2;
+- client filesystem or terminal methods;
+- client-provided MCP servers;
+- images, audio, files, or embedded resources in prompts;
+- session loading, listing, resumption, or durable ACP IDs across process restarts;
+- ACP model or mode configuration.
+
+The agent continues to use the connections, tools, credentials, and sandbox policy authored in the eve application. Prompt text and ACP metadata never establish an authenticated end-user principal.
+
+## Diagnose a connection
+
+ACP reserves stdout for newline-delimited JSON-RPC. eve sends compilation output, server logs, and diagnostics to stderr so they cannot corrupt the protocol stream.
+
+For a quick headless smoke test, run an ACP client such as `acpx` from the application root. `acpx` launches the ACP process itself; do not start `eve acp` separately.
+
+```sh
+npx acpx@latest \
+  --agent 'pnpm exec eve acp' \
+  exec 'Reply with exactly: ACP works'
+```
+
+When testing from the eve source checkout, use an authored fixture rather than the monorepo root, which does not provide an `eve` executable:
+
+```sh
+cd apps/fixtures/weather-agent
+npx acpx@latest --agent 'pnpm exec eve acp' exec 'Reply with exactly: ACP works'
+```
+
+If startup fails, inspect the ACP client's logs together with eve's stderr. A non-empty client MCP configuration, a mismatched working directory, and unsupported prompt content produce explicit protocol errors before model work begins.

docs/guides/meta.json

@@ -11,6 +11,7 @@
     "dynamic-workflows",
     "remote-agents",
     "dev-tui",
+    "acp",
     "frontend",
     "client"
   ]

docs/reference/cli.md

@@ -15,6 +15,7 @@ The `eve` binary (`bin: eve`) runs from your app root, and every command first l
 | `eve start`                   | Serve the built `.output/` app; prints the listening URL                                                                                              |
 | `eve dev`                     | Start the local dev server and open the terminal UI                                                                                                   |
 | `eve dev <url>`               | Connect the UI to an existing server URL (e.g. a remote deployment) instead of booting a local server                                                 |
+| `eve acp [url]`               | Serve the local application or an existing eve server URL as a stable ACP v1 agent over stdio                                                         |
 | `eve logs [logid]`            | Print an `eve dev` diagnostic log (the most recent when `logid` is omitted)                                                                           |
 | `eve logs ls`                 | List `eve dev` diagnostic logs, most recent first                                                                                                     |
 | `eve trace ls`                | List locally captured agent traces, most recent first                                                                                                 |
@@ -181,6 +182,8 @@ Pass a bare URL and the UI connects to that server instead of booting a local on
 | `--context-size <tokens>`           | number | none               | Model context window size, shown as a usage percentage                                    |
 | `--logs <mode>`                     | enum   | `stderr`           | Server/agent logs to show: `all` \| `stderr` \| `sandbox` \| `none`                       |
 
+`eve acp` reserves stdin and stdout for newline-delimited JSON-RPC and sends diagnostics to stderr. Without a URL, it supervises an isolated local development server. With a URL, it bridges ACP to that server's existing eve HTTP API and accepts the same URL credentials and request headers as `eve dev <url>`. See [Use eve through ACP](../guides/acp) for client configuration and capability limits.
+
 A fresh `eve init` passes `--input /model`. That bare local input starts onboarding: the TUI installs the Vercel CLI if needed, asks you to log in if needed, then opens `/model`. Other input stays editable in the prompt.
 
 For a URL target protected by HTTP Basic auth, put the credentials in the URL. eve sends them as a Basic `Authorization` header and strips them from the server URL before connecting:

packages/eve/package.json

@@ -303,6 +303,7 @@
     "undici": "8.9.0"
   },
   "devDependencies": {
+    "@agentclientprotocol/sdk": "1.3.0",
     "@ai-sdk/anthropic": "catalog:",
     "@ai-sdk/google": "catalog:",
     "@ai-sdk/mcp": "catalog:",

packages/eve/scripts/vendor-compiled/@agentclientprotocol/sdk.mjs

@@ -0,0 +1,26 @@
+import { mkdir, readFile, writeFile } from "node:fs/promises";
+import { dirname, join } from "node:path";
+
+const DECLARATIONS = [
+  ["acp.d.ts", "index.d.ts"],
+  ["jsonrpc.d.ts", "jsonrpc.d.ts"],
+  ["stream.d.ts", "stream.d.ts"],
+  ["schema/guards.gen.d.ts", "schema/guards.gen.d.ts"],
+  ["schema/index.d.ts", "schema/index.d.ts"],
+  ["schema/types.gen.d.ts", "schema/types.gen.d.ts"],
+];
+
+/** Vendor the stable ACP v1 SDK without adding it to eve's runtime dependencies. */
+export default {
+  packageName: "@agentclientprotocol/sdk",
+  compiledPath: "@agentclientprotocol/sdk",
+  bundling: "standalone",
+  copyDeclarations: async ({ destinationRoot, packageInfo }) => {
+    const sourceRoot = join(packageInfo.packageRoot, "dist");
+    for (const [sourceFile, destinationFile] of DECLARATIONS) {
+      const destinationPath = join(destinationRoot, destinationFile);
+      await mkdir(dirname(destinationPath), { recursive: true });
+      await writeFile(destinationPath, await readFile(join(sourceRoot, sourceFile)), "utf8");
+    }
+  },
+};

packages/eve/scripts/vendor-compiled/index.mjs

@@ -3,6 +3,7 @@
  * the orchestrator passes to `runVendor`. Adding a new vendored package
  * means writing a new per-package file and importing it here.
  */
+import acpSdk from "./@agentclientprotocol/sdk.mjs";
 import anthropic from "./@ai-sdk/anthropic.mjs";
 import google from "./@ai-sdk/google.mjs";
 import mcp from "./@ai-sdk/mcp.mjs";
@@ -48,6 +49,7 @@ import zod from "./zod.mjs";
 import zodValidationError from "./zod-validation-error.mjs";
 
 export const MODULES = [
+  acpSdk,
   anthropic,
   chat,
   chatAdapterSlack,