Pi Antigravity Guard

@benjamolina/pi-antigravity-guard is a static Pi extension that registers the text-only antigravity-guard provider. It uses Pi-managed OAuth credentials and the existing Antigravity OAuth endpoint and quota path; it does not provide alternate credential routes, quota pools, fallback, or model substitution.

Use

Install the package in Pi, then run:

/login antigravity-guard

Choose browser login, or choose manual login and paste the complete callback URL. The loopback callback uses fixed port 51121; browser callback failures, remote shells, and port conflicts can use the manual callback-URL flow.

Text registration is not tool enablement

All seven rows below are registered for text. The exact antigravity-gemini-3.8-flash off route is enabled for tools from recorded direct evidence; every other production route is not enabled for tools, so its context with a declaration, assistant tool call, or tool result fails locally before any network request. Text-only requests retain their released behavior.

| Public ID | Exposed Pi levels | Tool state | Admission | |---|---|---|---| | antigravity-gemini-3.8-flash | off, low, medium, high | Enabled (off, low, medium, high) | pi-json-tool-loop/gemini-3.8-flash-off-v1 | | antigravity-gemini-3.7-flash | off, low, medium, high | Enabled (off, low, medium, high) | pi-json-tool-loop/gemini-3.7-flash-off-v1 | | antigravity-gemini-3.6-flash | off, low, medium, high | Enabled (off, low, medium, high) | pi-json-tool-loop/gemini-3.6-flash-off-v1 | | antigravity-gemini-3.1-pro | off, low, high | Enabled (off, low, high) | pi-json-tool-loop/gemini-3.1-pro-off-v1 | | antigravity-claude-sonnet-4.6 | off, high | Enabled (off, high) | pi-json-tool-loop/claude-sonnet-4.6-off-v1 | | antigravity-claude-opus-4.6-thinking | off, high | Enabled (off, high) | pi-json-tool-loop/claude-opus-4.6-thinking-off-v1 | | antigravity-gpt-oss-120b | off, medium | Enabled (off, medium) | pi-json-tool-loop/gpt-oss-120b-off-v1 |

off is available for every row even though it is omitted from Pi's level map; omitted reasoning also selects that row's off route. Unsupported levels are not advertised and are rejected before transport. antigravity-gemini-3.5-flash is not registered or advertised as supported because its recorded HTTP-200 response lacks the strict terminal metadata required for admission. A future fixture-qualified route remains disabled for ordinary tool use; only separately authorized direct validation for the exact route may make it enabled.

Claude Sonnet and Claude Opus remain disabled until declaration, call, result replay, thinking-signature, resume, interruption, and continuation evidence is recorded for each exact route. Only Gemini 3.8 Flash off is enabled by this package release.

Opt-in direct tool-loop validation

Maintainers can run npm run build:pi followed by npx tsx scripts/pi-tool-loop-probe.ts --live --expect-enabled to verify the directly admitted Gemini 3.8 Flash off route. The isolated runner invokes Pi in --mode json, passes the deterministic non-terminating pi_evidence_echo prompt positionally, drains its event stream, and completes after Pi emits agent_end and the child exits. It stores only the passing route and sanitized assertions; it never stores message contents, tool details, names, IDs, arguments, credentials, headers, or raw provider output. Other routes remain fail-closed.

Tool preflight boundaries

Tool-bearing requests are never silently downgraded to text. When an exact route is eventually enabled, declarations are retained in order and omitted or auto choice serializes as AUTO; explicit none serializes as NONE. Forced, required, named, unknown, and constrained-sampling choices are rejected before transport.

Only the evidence-enabled Gemini 3.8 Flash off route uses the parametersJsonSchema profile. Its hermetically verified preflight preserves ordinary JSON Schema constraints and JSON values in canonical immutable output, including safe local RFC 6901 $ref expansion (# and #/...) with resolved definitions removed. External, malformed, unresolved, cyclic, or otherwise unsafe references fail closed before transport. This is local serialization and safety evidence, not direct live backend acceptance of constrained or reference-based schemas. Tool results must match the exact call ID and name, remain text-only, and are replayed in assistant source-call order; image-bearing or ambiguous results are rejected. A missing persisted result uses the documented failed response only during context reconstruction.

Text catalog limits and safety

| Public ID | Exposed Pi levels | Context / output | |---|---|---:| | antigravity-gemini-3.8-flash | off, low, medium, high | 1,048,576 / 65,536 | | antigravity-gemini-3.7-flash | off, low, medium, high | 1,048,576 / 65,536 | | antigravity-gemini-3.6-flash | off, low, medium, high | 1,048,576 / 65,536 | | antigravity-gemini-3.1-pro | off, low, high | 1,048,576 / 65,535 | | antigravity-claude-sonnet-4.6 | off, high | 250,000 / 64,000 | | antigravity-claude-opus-4.6-thinking | off, high | 250,000 / 64,000 | | antigravity-gpt-oss-120b | off, medium | 131,072 / 32,768 |

An explicit maxTokens must be a positive integer no greater than the row's output limit. For a route with a positive finite thinking budget, it must also be greater than that budget. When maxTokens is omitted, the provider uses 4,096 unless a larger finite thinking budget needs a 1,024-token answer reserve, always bounded by the row's output limit. Custom thinkingBudgets are unsupported and rejected.

• Costs are reported as zero because subscription usage is unpriced, not because access is free.
• The catalog is static: it performs no startup or runtime model discovery, catalog synchronization, or dynamic registration.
• It has no account rotation, quota fallback, model substitution, image support, or enabled tools beyond the directly admitted Gemini 3.8 Flash off route.

To remove it, disable or uninstall @benjamolina/pi-antigravity-guard and reload Pi. Removal does not delete Pi-managed credentials or revoke tokens.