setup

Those arguments must never reach a shell

$ARGUMENTS is substituted into this file as text, so a shell receiving it would evaluate whatever it contains — $(…), backticks, ;, |. Measured on the job commands: $(echo INJECTED) was executed before Node ever started.

Read the argument text, then assemble the command from fixed pieces only. Never place the argument text, or any fragment of it, into a command, and never pass it as a single quoted string. Every value below must be one you checked against its list and then wrote out yourself — chosen, never copied:

• --engine <value>: auto, gemini, agy
• --probe-agy, --probe-gemini, --enable-review-gate, --disable-review-gate, --json: literal flags, no value

If a value is not in its set, stop and say so rather than passing it through to find out.

Run this exactly as written — --json belongs inside the quoted argument string. A token placed beside that quoted string makes it a second argv element, and every flag inside it is then read as one positional and ignored, which is how /gemini:setup --engine gemini came back reporting a different engine:

node "${CLAUDE_PLUGIN_ROOT}/scripts/gemini-companion.mjs" setup --json [verified flags]

Gemini CLI and AGY are first-class supported engines. Each is a conditional dependency: the user only needs the binary for the engine they select. In auto mode Gemini is checked first because it exposes the plugin's JSON/model contract, then AGY is checked; that order does not make AGY an optional or lower-tier integration. Drive the install decisions below off the setup JSON's requestedEngine field, which already resolves both the --engine flag and the GEMINI_ENGINE environment variable — do not branch on the raw $ARGUMENTS text.

If the result says Gemini CLI is unavailable (gemini.available is false), npm is available, and requestedEngine is not agy:

• Use AskUserQuestion exactly once to ask whether Claude should install Gemini CLI now.
• Put the install option first and suffix it with (Recommended).
• Use these two options:
  • Install Gemini CLI (Recommended)
  • Skip for now
• If the user chooses install, run:

npm install -g @google/gemini-cli

• Then rerun:

node "${CLAUDE_PLUGIN_ROOT}/scripts/gemini-companion.mjs" setup --json [verified flags]

When requestedEngine is agy and AGY is unavailable (agy.available is false):

• Use AskUserQuestion exactly once to ask whether Claude should install AGY now.
• Put the install option first and suffix it with (Recommended).
• Use these two options:
  • Install AGY (Recommended)
  • Skip for now
• If the user chooses install, run:

curl -fsSL https://antigravity.google/cli/install.sh | bash

• Then rerun:

node "${CLAUDE_PLUGIN_ROOT}/scripts/gemini-companion.mjs" setup --json [verified flags]

Do not ask about installation when:

• the selected engine is already available (even if it still needs authentication), or
• Gemini CLI is the missing selected/auto candidate and npm is unavailable, or
• the only missing engine is AGY and requestedEngine is not agy. In that case AGY is not the selected conditional dependency, so do not push its installation.

When requestedEngine is agy and AGY is unavailable, the AGY install prompt above takes precedence even if Gemini CLI is already present — the user routed to AGY (via --engine agy or GEMINI_ENGINE=agy), so do not silently fall back to Gemini.

AGY authentication cannot be read off disk, so an unprobed --engine agy reports readyState: "partial" with agyAuth.state: "unknown" — that is "not checked", not "not signed in". When the user asks whether AGY is ready, or when they are about to act on a partial verdict, rerun with --probe-agy:

node "${CLAUDE_PLUGIN_ROOT}/scripts/gemini-companion.mjs" setup --json --probe-agy [verified flags]

It asks AGY a read-only question the account has to answer, so it verifies the login without starting a turn or spending quota (AGY 1.1.11+; below that it declines and says so). A verified AGY then reports readyState: "ready"; a probe that comes back logged-out reports not-ready, and the fix is to run agy once interactively — or to use one of AGY's non-interactive credentials (ADC and Enterprise/WIF on 1.1.10+, GEMINI_API_KEY with modelProvider: "gemini" on 1.1.13+).