Building CLI backend plugins

CLI backend plugins let OpenClaw call a local AI CLI as a text inference backend. The backend appears as a provider prefix in model refs:

acme-cli/acme-large

Use a CLI backend when the upstream integration is already exposed as a local command, when the CLI owns local login state, or when the CLI is a useful fallback if API providers are unavailable.

# What the plugin owns

A CLI backend plugin has three contracts:

The manifest is discovery metadata. It does not execute the CLI and does not register runtime behavior. Runtime behavior starts when the plugin entry calls api.registerCliBackend(...).

# Minimal backend plugin

{
  "name": "@acme/openclaw-acme-cli",
  "version": "1.0.0",
  "type": "module",
  "openclaw": {
    "extensions": ["./index.ts"],
    "compat": {
      "pluginApi": ">=2026.3.24-beta.2",
      "minGatewayVersion": "2026.3.24-beta.2"
    },
    "build": {
      "openclawVersion": "2026.3.24-beta.2",
      "pluginSdkVersion": "2026.3.24-beta.2"
    }
  },
  "dependencies": {
    "openclaw": "^2026.3.24"
  },
  "devDependencies": {
    "typescript": "^5.9.0"
  }
}

{
  "id": "acme-cli",
  "name": "Acme CLI",
  "description": "Run Acme's local AI CLI through OpenClaw",
  "cliBackends": ["acme-cli"],
  "setup": {
    "cliBackends": ["acme-cli"],
    "requiresRuntime": false
  },
  "activation": {
    "onStartup": false
  },
  "configSchema": {
    "type": "object",
    "additionalProperties": false
  }
}

import { definePluginEntry } from "openclaw/plugin-sdk/plugin-entry";
import {
  CLI_FRESH_WATCHDOG_DEFAULTS,
  CLI_RESUME_WATCHDOG_DEFAULTS,
  type CliBackendPlugin,
} from "openclaw/plugin-sdk/cli-backend";

function buildAcmeCliBackend(): CliBackendPlugin {
  return {
    id: "acme-cli",
    liveTest: {
      defaultModelRef: "acme-cli/acme-large",
      defaultImageProbe: false,
      defaultMcpProbe: false,
      docker: {
        npmPackage: "@acme/acme-cli",
        binaryName: "acme",
      },
    },
    config: {
      command: "acme",
      args: ["chat", "--json"],
      output: "json",
      input: "stdin",
      modelArg: "--model",
      sessionArg: "--session",
      sessionMode: "existing",
      sessionIdFields: ["session_id", "conversation_id"],
      systemPromptFileArg: "--system-file",
      systemPromptWhen: "first",
      imageArg: "--image",
      imageMode: "repeat",
      reliability: {
        watchdog: {
          fresh: { ...CLI_FRESH_WATCHDOG_DEFAULTS },
          resume: { ...CLI_RESUME_WATCHDOG_DEFAULTS },
        },
      },
      serialize: true,
    },
  };
}

export default definePluginEntry({
  id: "acme-cli",
  name: "Acme CLI",
  description: "Run Acme's local AI CLI through OpenClaw",
  register(api) {
    api.registerCliBackend(buildAcmeCliBackend());
  },
});

# Config shape

CliBackendConfig describes how OpenClaw should launch and parse the CLI:

Prefer the smallest static config that matches the CLI. Add plugin callbacks only for behavior that really belongs to the backend.

# Advanced backend hooks

CliBackendPlugin can also define:

Keep these hooks provider-owned. Do not add CLI-specific branches to core when a backend hook can express the behavior.

# MCP tool bridge

CLI backends do not receive OpenClaw tools by default. If the CLI can consume an MCP configuration, opt in explicitly:

return {
  id: "acme-cli",
  bundleMcp: true,
  bundleMcpMode: "codex-config-overrides",
  config: {
    command: "acme",
    args: ["chat", "--json"],
    output: "json",
  },
};

Supported bridge modes are:

Only enable the bridge when the CLI can actually consume it. If the CLI has its own built-in tool layer that cannot be disabled, set nativeToolMode: "always-on" so OpenClaw can fail closed when a caller requires no native tools.

# User configuration

Users can override any backend default:

{
  agents: {
    defaults: {
      cliBackends: {
        "acme-cli": {
          command: "/opt/acme/bin/acme",
          args: ["chat", "--json", "--profile", "work"],
          modelAliases: {
            large: "acme-large-2026",
          },
        },
      },
      model: {
        primary: "openai/gpt-5.5",
        fallbacks: ["acme-cli/large"],
      },
    },
  },
}

Document the minimum override users are likely to need. Usually that is only command when the binary is outside PATH.

# Verification

For bundled plugins, add a focused test around the builder and setup registration, then run the plugin's targeted test lane:

pnpm test extensions/acme-cli

For local or installed plugins, verify discovery and one real model run:

openclaw plugins inspect acme-cli --runtime --json
openclaw agent --message "reply exactly: backend ok" --model acme-cli/acme-large

If the backend supports images or MCP, add a live smoke that proves those paths with the real CLI. Do not rely on static inspection for prompt, image, MCP, or session-resume behavior.

# Checklist

OPENCLAW_DOCS_MARKER:calloutOpen:Q2hlY2s package.json has openclaw.extensions and built runtime entries for published packages OPENCLAW_DOCS_MARKER:calloutClose:

OPENCLAW_DOCS_MARKER:calloutOpen:Q2hlY2s openclaw.plugin.json declares cliBackends and intentional activation.onStartup OPENCLAW_DOCS_MARKER:calloutClose:

OPENCLAW_DOCS_MARKER:calloutOpen:Q2hlY2s setup.cliBackends is present when setup/model discovery should see the backend cold OPENCLAW_DOCS_MARKER:calloutClose:

OPENCLAW_DOCS_MARKER:calloutOpen:Q2hlY2s api.registerCliBackend(...) uses the same backend id as the manifest OPENCLAW_DOCS_MARKER:calloutClose:

OPENCLAW_DOCS_MARKER:calloutOpen:Q2hlY2s User overrides under agents.defaults.cliBackends.<id> still win OPENCLAW_DOCS_MARKER:calloutClose: