Gemini CLI

Agent ID: gemini

Google's Gemini CLI. Speaks ACP via a peer-installed bridge package.

Install

npm install -g @google/gemini-cli
gemini auth login

The @google/gemini-cli package must be installed as a peer - it is not bundled with agents-wire.

Quick Start

import { agents } from "@pivanov/agents-wire";

const result = await agents.ask(
  "gemini",
  "Summarize this PR",
  {
    permission: "auto-allow",
  },
);

console.log(result.text);

Model Selection

options.model is forwarded as ACP modelPreference (best-effort). The gemini --acp bridge does not accept CLI model flags, so model selection depends entirely on whether the ACP bridge implements setSessionConfigOption. options.effort is sent via the same mechanism (best-effort).

To see which models Gemini currently advertises for a session, read session.configOptions:

import { createSession } from "@pivanov/agents-wire";

const session = await createSession("gemini");
const opts = session.configOptions ?? [];
const modelOpt = opts.find((o) => o.configId === "model" && o.type === "select");

if (modelOpt && modelOpt.type === "select") {
  console.log(modelOpt.options); // live model list from the agent
}

Capabilities

Feature	Supported
ask / stream / session	✅
askJson	✅
MCP stdio	✅
MCP http/sse	✅
Session listing (listSessions)	❌
Tool call interception	✅

Cost Tracking

Gemini reports per-turn costUsd. Full cost tracking and maxCostUsd budget enforcement work.

Auth Failure Detection

If gemini auth login hasn't been run or credentials have expired, the SDK throws AgentUnauthenticatedError.

Gotchas

• The @google/gemini-cli package is a peer dependency - install it separately.
• Session listing is not supported; listSessions() throws CapabilityNotSupportedError.
• Gemini CLI requires a Google account with the Gemini API enabled, or a paid API key.