API Reference

1. Node SDK — caveman import

import {
    AuthStorage,
    createAgentSession,
    ModelRegistry,
    SessionManager,
} from "@juliusbrussee/caveman-code";

const { session } = await createAgentSession({
    sessionManager: SessionManager.inMemory(),
    authStorage: AuthStorage.create(),
    modelRegistry: ModelRegistry.create(AuthStorage.create()),
});

const result = await session.prompt("What files are in the current directory?");
console.log(result.text);

Useful for: building a custom UI on top of caveman-code's runtime, embedding cave in a larger app, scripted batch runs.

Full TypeScript types are exported from the caveman package. See packages/coding-agent for source.

2. Daemon SDK — @juliusbrussee/caveman-sdk

npm install @juliusbrussee/caveman-sdk

import { CaveClient } from "@juliusbrussee/caveman-sdk";

const client = new CaveClient({
    host: "localhost:39245",
    token: process.env.CAVE_TOKEN,
});

const session = await client.sessions.create({
    model: "claude-sonnet-4",
    cwd: "/path/to/repo",
});

await session.prompt("explain this codebase");

for await (const event of session.events()) {
    if (event.type === "token") process.stdout.write(event.text);
    if (event.type === "tool_call") console.error("[tool]", event.name);
    if (event.type === "done") break;
}

The @juliusbrussee/caveman-sdk package is generated from the daemon's OpenAPI spec. See Daemon for the protocol details.

3. JSON-RPC over stdin/stdout

caveman --mode rpc

JSONL on stdin, JSONL on stdout. One request per line.

Methods:

Example:

{"jsonrpc":"2.0","id":1,"method":"session.create","params":{"model":"claude-sonnet-4"}}
{"jsonrpc":"2.0","id":2,"method":"session.prompt","params":{"sessionId":"abc","text":"hello"}}

Useful for: integrating cave with editors (LSP-style), building shell scripts that pipe through caveman-code, writing other-language clients.

4. Print mode + JSON output

For one-shot integrations:

caveman -p "summarize this file" < src/foo.ts
caveman --mode json "list todos in this repo"
caveman exec "lint and fix" --output-schema schema.json

--output-schema validates the model's final response against a JSON Schema. Useful for CI gates.

Stable JSON event stream:

{"type":"session.start","sessionId":"abc","model":"claude-sonnet-4"}
{"type":"tool.call","tool":"Read","args":{"path":"src/foo.ts"}}
{"type":"tool.result","tool":"Read","ok":true}
{"type":"token","text":"This file..."}
{"type":"session.end","cost":0.012,"tokens":{"in":1200,"out":80}}

The schema is versioned. Pin --protocol-version=v1 for stability across cave releases.

OpenAPI spec

The daemon serves its own OpenAPI 3.1 spec:

caveman serve &
curl http://localhost:39245/openapi.yaml

Or browse the spec on GitHub: packages/coding-agent/openapi.yaml.

Extension API (in-process)

If you'd rather load TypeScript modules at session start:

// .cave/extensions/my-ext.ts
import type { ExtensionAPI } from "@juliusbrussee/caveman-code";

export default function (api: ExtensionAPI) {
    api.registerTool({ name: "deploy", schema: { ... }, handler: async (args) => { ... } });
    api.registerCommand("stats", { handler: async () => "..." });
    api.on("tool_call", async (event, ctx) => {
        // ...
    });
}

40+ event types. Full docs at packages/coding-agent/docs/extensions.md.

Choosing a surface