adk: v1.6.0

1.6.0 (2026-08-05)

Features

• Add bearerTokenUserBuilder for A2A authentication (Part 1/2) (#562) (f077722)
• CLI-level A2A authenticator for the dev server and Cloud Run deploy (Part 2/2) (#559) (0c0bba2)
• Support ttl and expireTime session-expiration options in VertexAiSessionService.createSession (#561) (b390217)
• tools: add getUserChoiceTool and requestInputTool for parity with adk-python (#506) (03abf76)
• Validate tool callback response types and prevent state event pollution (#505) (b99f21b)

Bug Fixes

• a2a: stop restoring event branch from A2A peer metadata (#606) (0000925)
• accept the derived allowedTools alias in skill frontmatter validation (#560) (fcfd043)
• artifacts: isolate in-memory composite keys (#576) (693a1d7)
• core: fall back to node:crypto so randomUUID cannot throw on Node (#599) (3dc1b20)
• core: use a cryptographically secure source for randomUUID (#577) (81bcc8d)
• detect PowerShell 7+ (pwsh) in the UnsafeLocalCodeExecutor SHELL branch (#568) (ce0e474)
• fail fast when a Vertex AI Express Mode API key cannot be used (#563) (e1112c6)
• gate the set_model_response workaround on canUseOutputSchemaWithTools (adk-python parity) (#580) (5b65ee1)
• parse JSON bodies only in the toA2a server (drop express.urlencoded) (#558) (605b469)
• pass -NoProfile to spawned PowerShell and /D to cmd.exe in UnsafeLocalCodeExecutor (#566) (b56761b)
• reject zip-slip entries and non-bare skill names when loading zipped skills (adk-python parity) (#584) (4fe80b0)
• runner: persist events returned by onEventCallback (#575) (c4c5582)
• security: prevent prototype pollution via untrusted map keys (#619) (2c07ad3)
• surface root-cause MCP session errors instead of swallowing them (#527) (13d7304)
• treat @google/genai ApiError 404 as session not found in VertexAiSessionService (#567) (5331c77)
• utils: fix sibling-directory escape in materializeFiles path check (#603) (868ca1f)