Antigravity (Gemini)

The Antigravity adapter drives Google's official agy CLI headlessly behind the Adapter contract: agy --output-format json -p for one-shot runs, agy --conversation <id> -p to revise a conversation, and agy --output-format stream-json -p for incremental events — all under your own Google login.

Unofficial

Not affiliated with or endorsed by Google. This package shells out to the agy binary you already have installed and authenticated — it never impersonates the service, shares credentials, or circumvents rate limits.

Install

npm install @toragonite/agent-mesh @toragonite/agent-mesh-gemini

Requires the agy CLI installed and logged in. Antigravity keeps its credentials in the Electron app's data directory — there is no CLI login/status subcommand, so Auth below shells out instead of reading a file.

Options

new GeminiAdapter(options?) — every option defaults to the real implementation and is overridable for testing:

Option	Type	Default	Description
exec	ExecFn	nodeExec	Run-to-completion process seam.
lineStream	LineStreamFn	nodeLineStream	Streaming process seam backing stream().
binary	string	'agy'	The agy executable path or command name.
defaultAccount	Account	—	Account used when a call passes none. Its configDir sets AGY_HOME (undocumented for agy; see Behaviour notes).
env	Record<string, string | undefined>	process.env	Environment seam — the base of every child env and every env read.
authTimeoutMs	number	20000	Wall-clock cap for the agy models auth probe.

Run and resume

import { Fleet } from '@toragonite/agent-mesh'
import { GeminiAdapter } from '@toragonite/agent-mesh-gemini'

const fleet = new Fleet().register(new GeminiAdapter())

// Antigravity answers a one-word prompt in ~12-15s; set timeoutMs generously
// (see Latency below).
const res = await fleet.run(
  { prompt: 'Reply with exactly: MESH-OK', timeoutMs: 60_000 },
  { policy: { prefer: ['gemini'] } },
)
console.log(res.status, res.conversationId, res.text)

// Continue that conversation by id.
const more = await fleet.resume('gemini', res.conversationId, 'Now say it backwards.', {
  timeoutMs: 60_000,
})
console.log(more.text)

You can also drive the adapter directly:

const agy = new GeminiAdapter({ binary: 'agy' /* default */ })
const res = await agy.run({ prompt: 'hello', model: 'gemini-3.6-flash-high' })

Stream

const agy = new GeminiAdapter()
for await (const ev of agy.stream({ prompt: 'Write a haiku about routing.', timeoutMs: 60_000 })) {
  if (ev.type === 'text') process.stdout.write(ev.text)
  else if (ev.type === 'usage') console.error('usage', ev.usage)
  else if (ev.type === 'done') console.error('\ndone', ev.result.status, ev.result.conversationId)
  else if (ev.type === 'error') console.error('error', ev.message)
}

Streaming maps agy --output-format stream-json to agent-mesh RunEvents: the init event only records the conversation id; only an agent_response step with a non-empty text_delta becomes a text event (other step types — user_input, checkpoint, … — are skipped, since the contract has no event for them and their per-step usage is partial, not authoritative); the terminal result event emits a usage event followed by a done event carrying the same RunResult a non-streaming run() would produce. An empty prompt throws synchronously at the stream() call, before any process spawns. If the stream ends with no result event: a timeout yields a done result with status: 'incomplete' (never an error event); a non-zero exit yields an error event with the exit code and the child's stderr tail.

Models

availableModels() returns a static catalog and spawns nothing, because Fleet.route() calls it on the routing hot path:

id	latency	note
gemini-3.6-flash-high	fast
gemini-3.6-flash-medium	fast
gemini-3.6-flash-low	fast
gemini-3.5-flash-high	fast
gemini-3.5-flash-medium	fast
gemini-3.5-flash-low	fast
gemini-3.1-pro-high	slow
gemini-3.1-pro-low	slow
claude-sonnet-4-6	fast	resold — selecting it spends Anthropic quota, not Gemini's
claude-opus-4-6-thinking	slow	resold — selecting it spends Anthropic quota, not Gemini's
gpt-oss-120b-medium	fast	resold — selecting it spends the provider's quota, not Gemini's

Resold models

Three catalog entries are reachable through agy but bill an other vendor's quota, not Google's. Routing another vendor's quota through the Gemini adapter defeats the point of a multi-vendor fleet — prefer registering that vendor's own adapter instead.

There is no auth-mode gating — every entry is selectable under one Google login. The latency classes are a provisional pin (a best guess at interactive-vs-deep-reasoning behavior, not measured). No entry is marked default: when a task names no model, run() omits --model and the CLI applies its own default — claiming a default here would be false. A model id outside this catalog still runs, with a model <id> not in known catalog note on the result.

Static vs live

availableModels() is the fast, hermetic path for routing. The authoritative but slow counterpart is fetchLiveModels(), which runs agy models, skips the Fetching available models... chatter line, and parses each TAB-separated id\tlabel row:

import { fetchLiveModels } from '@toragonite/agent-mesh-gemini'
const live = await fetchLiveModels() // ModelInfo[] — or [] on any failure

Any failure (spawn error, non-zero exit, timeout, unparseable output) resolves to []; it never throws.

Auth

authStatus() runs agy models — the only auth probe Antigravity exposes, since there is no readable local credential file and no status/login subcommand. Exit 0 with at least one parseable model line reports { loggedIn: true, mode: 'google' }; anything else (non-zero exit, missing binary, timeout, unparseable output) reports { loggedIn: false }. It never throws and never returns a detail — the CLI exposes no account identifier.

This costs a network round-trip, so it is deliberately not on the routing path — only availableModels() (static) is.

Quota

quota() returns null unconditionally, and capabilities.quota is false. Antigravity exposes no usage endpoint that has been verified. This is a deliberate "unknown headroom" signal, not a stub filled in casually: fabricating { allowed: true, windows: [] } would tell the Fleet's router that an exhausted account has full headroom. Returning null instead means the router treats Gemini's headroom as unconfirmed rather than believing a fabricated full tank — it still considers the adapter, just without quota-ranking it against vendors that report real usage. Never throws.

Behaviour notes

• Trailing-newline normalization. agy terminates its printed answer with a newline the other agent-mesh vendors do not emit. For cross-vendor comparability, run()/resume() and the stream's done result strip exactly one trailing newline (\r\n or \n) from the final text. Interior newlines are preserved, and a second trailing newline is kept. Streaming text deltas are passed through raw — only the final assembled text is normalized.
• allowedTools is ignored. agy has no equivalent flag, so task.allowedTools is dropped and the result carries an allowedTools not supported by agy; ignored note.
• account.configDir → AGY_HOME. There is no documented config-dir env var for agy. When you pass account.configDir, the adapter sets AGY_HOME to it and adds a note that Antigravity account isolation via this variable is unverified. An explicitly passed account with no configDir means the ambient login and does not inherit a default account's directory.
• Latency. A one-word answer is observed at 12–15 seconds (versus ~5s for Claude Code/Codex); agy's own --print-timeout defaults to 5m0s. Set timeoutMs generously — a timeout resolves status: 'incomplete' (it never throws), so too tight a cap silently truncates real answers.
• No secrets. No token or credential value appears in any result, note, detail, error, or raw. There are no tokens on this path, but the rule holds regardless.