build(deps): bump google-adk from 2.7.1 to 2.9.0

[dependabot]

Bumps google-adk from 2.7.1 to 2.9.0.

Release notes

Sourced from google-adk's releases.

v2.9.0

Changelog

2.9.0 (2026-09-10)

Highlights

This release focuses on agent resilience and ecosystem integration by introducing automatic model failover, native voice support via LiveKit, and compatibility with MCP SDK 2.x.

• Models: Safeguard agent uptime by automatically failing over to backup models when the primary model encounters errors. (c300b8d)
• Integrations: Build rich voice and telephony agents using the newly added LiveKit runner. (f277d91)
• Workflows: Simplify graph workflow management by authoring and loading ADK 2.0 graphs directly from declarative YAML configurations. (2a9461b)
• MCP: Work with MCP SDK 2.x servers as well as 1.x. Installs continue to resolve 1.x by default; install 2.x deliberately to opt in. (856acf2)

Breaking changes

• Workflow node resumption: A node that failed now runs again when the workflow resumes, where before it replayed as though it had completed. Make node bodies idempotent: a node that performs an external side effect and then fails will perform that side effect again on every resume.
• GCS tool local paths: The GCS tools now read and write local files only inside the directory named by local_file_root, and refuse local file access entirely when that setting is absent. Paths may be absolute or relative, and are judged by where they resolve.
• In-memory sessions only: InMemorySessionService now raises SessionNotFoundError when an event is appended to a session it does not hold, instead of accepting the event and discarding it. The database-backed services already behaved this way, so this affects in-memory sessions alone.

Two further changes are marked breaking in the commit log but do not affect a default installation. Nested workflow retry changes behavior only for a node that already sets retry_config. The MCP SDK 2.x field handling applies only if you install MCP 2.x deliberately, which this release does not resolve to.

⚠ BREAKING CHANGES

• retry a nested workflow when a node inside it fails
• confine GCS tool local file paths to a configured root
• rerun a failed node on resume instead of replaying it as complete
• raise SessionNotFoundError when appending to an unknown session
• mcp: under MCP SDK 2.x, fields a server sends that the SDK does not declare no longer reach the caller. 2.x closed its models, so an unknown key on a CallToolResult, or on a tool declaration read via raw_mcp_tool, is discarded during validation before ADK sees it. _meta is unaffected: it is a declared field and still arrives. Nothing in ADK can restore the others; a server that relies on vendor extensions should move them under _meta. On 1.x they still arrive as before.

Features

• add a2a_state_forwarding sample (1b28de4)
• add FallbackModel for automatic failover between models (c300b8d)
• add get_authenticated_url and get_signed_url to GcsArtifactService (10ac52b)
• add ignore_args option to tool trajectory evaluation (e2a213f)
• add transfer_reason to transfer_to_agent to prevent loops (22ab4d8)
• agent evaluations print detailed results when all tests pass (e1ae543), closes #3891
• generalize docker build and run for multicloud environments (0673f05)
• integrations: add LiveKit runner for voice and telephony (f277d91)
• load ADK 2.0 graph workflows from YAML configuration (2a9461b)
• mcp: support MCP SDK 2.x alongside 1.x (856acf2)
• support hyphenated column names in BigQuery tools (b736b0d)

... (truncated)

Changelog

Sourced from google-adk's changelog.

2.9.0 (2026-09-10)

Highlights

This release focuses on agent resilience and ecosystem integration by introducing automatic model failover, native voice support via LiveKit, and compatibility with MCP SDK 2.x.

• Models: Safeguard agent uptime by automatically failing over to backup models when the primary model encounters errors. (c300b8d)
• Integrations: Build rich voice and telephony agents using the newly added LiveKit runner. (f277d91)
• Workflows: Simplify graph workflow management by authoring and loading ADK 2.0 graphs directly from declarative YAML configurations. (2a9461b)
• MCP: Upgrade to MCP SDK 2.x capabilities seamlessly while retaining full backward compatibility with 1.x servers. (856acf2)

Breaking changes

• Workflow node resumption: A node that failed now runs again when the workflow resumes, where before it replayed as though it had completed. Make node bodies idempotent: a node that performs an external side effect and then fails will perform that side effect again on every resume.
• GCS tool local paths: The GCS tools now read and write local files only inside the directory named by local_file_root, and refuse local file access entirely when that setting is absent. Paths may be absolute or relative, and are judged by where they resolve.
• In-memory sessions only: InMemorySessionService now raises SessionNotFoundError when an event is appended to a session it does not hold, instead of accepting the event and discarding it. The database-backed services already behaved this way, so this affects in-memory sessions alone.

Two further changes are marked breaking in the commit log but do not affect a default installation. Nested workflow retry changes behavior only for a node that already sets retry_config. The MCP SDK 2.x field handling applies only if you install MCP 2.x deliberately, which this release does not resolve to.

⚠ BREAKING CHANGES

• retry a nested workflow when a node inside it fails
• confine GCS tool local file paths to a configured root
• rerun a failed node on resume instead of replaying it as complete
• raise SessionNotFoundError when appending to an unknown session
• mcp: under MCP SDK 2.x, fields a server sends that the SDK does not declare no longer reach the caller. 2.x closed its models, so an unknown key on a CallToolResult, or on a tool declaration read via raw_mcp_tool, is discarded during validation before ADK sees it. _meta is unaffected: it is a declared field and still arrives. Nothing in ADK can restore the others; a server that relies on vendor extensions should move them under _meta. On 1.x they still arrive as before.

Features

• add a2a_state_forwarding sample (1b28de4)
• add FallbackModel for automatic failover between models (c300b8d)
• add get_authenticated_url and get_signed_url to GcsArtifactService (10ac52b)
• add ignore_args option to tool trajectory evaluation (e2a213f)
• add transfer_reason to transfer_to_agent to prevent loops (22ab4d8)
• agent evaluations print detailed results when all tests pass (e1ae543), closes #3891
• generalize docker build and run for multicloud environments (0673f05)
• integrations: add LiveKit runner for voice and telephony (f277d91)
• load ADK 2.0 graph workflows from YAML configuration (2a9461b)
• mcp: support MCP SDK 2.x alongside 1.x (856acf2)
• support hyphenated column names in BigQuery tools (b736b0d)
• telemetry: add ability to track skill loads (0cd24c8)
• telemetry: add script execution instrumentation (0dbc37d)
• telemetry: export logs over OTLP to telemetry.googleapis.com (5e6df42)

... (truncated)

Commits

• 1679384 chore: update last-release-sha for next main release
• ff85018 chore(release/candidate): release 2.9.0 (#7075)
• 48b28de fix(gcs): judge a local path by where it lands, not by whether it is absolute
• fb45e24 fix(flows): move before_tool_callback from prepare phase into per-tool execution
• 46edaa2 fix(mcp): keep resolving MCP 1.x by default
• 187a693 chore: release as 2.9.0
• b65be01 fix(bigquery): lazy-load Dataplex so BigQueryToolset imports without it
• 2880fbf docs: correct the heading in the llms-full.txt pointer
• 903f37f fix: defer local state/event mutation until Vertex append succeeds
• e4f1700 fix: keep the tool filter and name prefix when cloning a skill toolset
• Additional commits viewable in compare view

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