acpx 0.17.1

Highlights: Configured runtime initialization deadlines now stop unresponsive agents and clean up abandoned launches safely. Embedding hosts gain model inspection and session-specific permissions. Antigravity joins the built-in agents; its fixed-choice questions require an interactive client, including for existing custom launchers.

Changes

• Dependencies: update fs-safe to 0.12.0 and Zod to 4.6.5, including the matching native filesystem packages.
• Agents/built-ins: add the antigravity shortcut for Google's official ACP runtime, with platform launch arguments and account setup guidance. Thanks @superbiche.
• Runtime/embedding: inspect agent models without a runtime session store, with bounded discovery and awaited process cleanup.
• Runtime/embedding: resolve session-specific client permissions without allocating a separate runtime.

Breaking

• Antigravity/questions: cancel fixed-choice interaction questions with a user-answer-required error instead of selecting an answer through tool approval. This also applies to existing custom launchers and takes precedence over --approve-all, permission policies, and embedding host permission callbacks. Continue these conversations in an interactive client supporting Antigravity questions. Thanks @superbiche.

Fixes

• ACP/capabilities: enforce --no-fs and --no-terminal against direct agent requests, keeping registered methods aligned with each connection's advertised capabilities.
• Runtime/prompt admission: accept optional synchronous host authority checks through the final native prompt write, preventing revoked prompts from reaching the agent after preparation or transport queue waits; preserve cancellation results and retire connections closed by rejected writes.
• Runtime/startup: honor the configured initialization timeout, clean up unresponsive agents and observed descendants, and retire abandoned late launches without disturbing replacement connections. Thanks @saariuslystoned.

Package and verification

• npm acpx 0.17.1
• Registry tarball
• Integrity: sha512-VafoVDYO8xE/Pd/8hTwAR6eHoSJf3K119knfFfAjCVqGy8ilGtWoVRI8z7fm+Q1o+R1vKDo58MJoxDx6YIt1tQ==
• Published: 2026-09-20T04:05:13.343Z
• Source commit: 50a47ad10a75431cbc276ec9b555d11fe1f69c84
• Release CI: all twelve jobs passed, including Node 22/24/26, coverage, mutation, conformance, Slophammer, and docs.
• Trusted publication with provenance
• Startup before/after and process-cleanup proof