chore(release/candidate): release 1.26.0

[Jacksunwei]

🤖 I have created a release beep boop

1.26.0 (2026-02-24)

⚠ BREAKING CHANGES

• skill: colocate default skill SI with skilltoolset

Features

• [Core]

  • Add intra-invocation compaction and token compaction pre-request (485fcb8)
  • Use --memory_service_uri in ADK CLI run command (a7b5097)

• [Models]

  • Add /chat/completions integration to ApigeeLlm (9c4c445)
  • Add /chat/completions streaming support to Apigee LLM (121d277)
  • Expand LiteLlm supported models and add registry tests (d5332f4)

• [Tools]

  • Add load_skill_from_dir() method (9f7d5b3)
  • Agent Skills spec compliance — validation, aliases, scripts, and auto-injection (223d9a7)
  • BigQuery ADK support for search catalog tool (bef3f11)
  • Make skill instruction optimizable and can adapt to user tasks (21be6ad)
  • Pass trace context in MCP tool call's _meta field with OpenTelemetry propagator (bcbfeba)

• [Evals]

  • Introduce User Personas to the ADK evaluation framework (6a808c6)

• [Services]

  • Add generate/create modes for Vertex AI Memory Bank writes (811e50a)
  • Add support for memory consolidation via Vertex AI Memory Bank (4a88804)

• [A2A]

  • Add interceptor framework to A2aAgentExecutor (87fcd77)

• [Auth]

  • Add native support for id_token in OAuth2 credentials (33f7d11)
  • Support ID token exchange in ServiceAccountCredentialExchanger (7be90db), closes #4458

• [Integrations]

  • Agent Registry in ADK (abaa929)
  • Add schema auto-upgrade, tool provenance, HITL tracing, and span hierarchy fix to BigQuery Agent Analytics plugin (4260ef0)
  • Change default BigQuery table ID and update docstring (7557a92)
  • Update Agent Registry to create AgentCard from info in get agents endpoint (c33d614)

• [Web]

  • Enable dependency injection for agent loader in FastAPI app gen (34da2d5)

Bug Fixes

• Add OpenAI strict JSON schema enforcement in LiteLLM (2dbd1f2), closes #4573
• Add push notification config store to agent_to_a2a (4ca904f), closes #4126
• Add support for injecting a custom google.genai.Client into Gemini models (48105b4), closes #2560
• Add support for injecting a custom google.genai.Client into Gemini models (c615757), closes #2560
• Check both input_stream parameter name and its annotation to decide whether it's a streaming tool that accept input stream (d56cb41)
• deps: Increase pydantic lower version to 2.7.0 (dbd6420)
• edit copybara and BUILD config for new adk/integrations folder (added with Agent Registry) (37d52b4)
• Expand add_memory to accept MemoryEntry (f27a9cf)
• Fix pickling lock errors in McpSessionManager (4e2d615)
• fix typo in PlanReActPlanner instruction (6d53d80)
• handle UnicodeDecodeError when loading skills in ADK (3fbc27f)
• Improve BigQuery Agent Analytics plugin reliability and code quality (ea03487)
• Include list of skills in every message and remove list_skills tool from system instruction (4285f85)
• Invoke on_tool_error_callback for missing tools in live mode (e6b601a)
• Keep query params embedded in OpenAPI paths when using httpx (ffbcc0a), closes #4555
• Only relay the LiveRequest after tools is invoked (b53bc55)
• Parallelize tool resolution in LlmAgent.canonical_tools() (7478bda)
• race condition in table creation for DatabaseSessionService (fbe9ecc)
• Refactor LiteLLM streaming response parsing for compatibility with LiteLLM 1.81+ (e8019b1), closes #4225
• remove duplicate session GET when using API server, unbreak auto_session_create when using API server (445dc18)
• Remove experimental decorators from user persona data models (eccdf6d)
• Replace the global DEFAULT_USER_PERSONA_REGISTRY with a function call to get_default_persona_registry (2703613)
• skill: coloate default skill SI with skilltoolset (fc1f1db)
• Update agent_engine_sandbox_code_executor in ADK (ee8d956)
• Update agent_engine_sandbox_code_executor in ADK (dab80e4)
• Update sample skills agent to use weather-skill instead of weather_skill (8f54281)
• update Spanner query tools to async functions (1dbcecc)
• use correct msg_out/msg_err keys for Agent Engine sandbox output (b1e33a9)
• web: allow session resume without new message (30b2ed3)

Code Refactoring

• Extract reusable function for building agent transfer instructions (e1e0d63)
• Extract reusable private methods (976a238)
• Extract reusable private methods (42eeaef)
• Extract reusable private methods (706f9fe)

Documentation

• add thinking_config in generate_content_config in example agent (c6b1c74)

---

This PR was generated with Release Please. See documentation.

[gemini-code-assist]

Summary of Changes

Hello @Jacksunwei, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request marks a significant milestone with the release of version 2.0.0 for the ADK Python library. It bundles a substantial collection of new features, critical bug fixes, and code refactorings aimed at enhancing the library's capabilities, stability, and developer experience. Key areas of improvement include expanded LLM integrations, advanced agent functionalities, refined memory management, and robust authentication mechanisms, alongside general code quality and documentation updates.

Highlights

• Breaking Change: The default skill instruction (SI) has been collocated with the skilltoolset, which is a breaking change.
• New Features: Added comprehensive support for /chat/completions in ApigeeLlm, including streaming capabilities. Introduced new generate/create modes for Vertex AI Memory Bank writes and support for memory consolidation.
• Agent Enhancements: Implemented an interceptor framework for A2aAgentExecutor, introduced an Agent Registry in ADK, and improved Agent Skills for spec compliance with validation, aliases, scripts, and auto-injection.
• Authentication and Analytics: Added native support for id_token in OAuth2 credentials and enhanced the BigQuery Agent Analytics plugin with schema auto-upgrade, tool provenance, HITL tracing, and span hierarchy fixes.
• Bug Fixes and Refactoring: Addressed numerous bugs including OpenAI strict JSON schema enforcement in LiteLLM, race conditions in DatabaseSessionService, and improved LiteLLM streaming response parsing. Several reusable private methods and functions were extracted for better code organization.

🧠 New Feature in Public Preview: You can now enable Memory to help Gemini Code Assist learn from your team's feedback. This makes future code reviews more consistent and personalized to your project's style. Click here to enable Memory in your admin console.

Changelog

• .github/.release-please-manifest.json
  • Updated the project version from "1.25.1" to "2.0.0".
• CHANGELOG.md
  • Added release notes for version 2.0.0, detailing breaking changes, new features, bug fixes, code refactoring, and documentation updates.
• src/google/adk/version.py
  • Updated the __version__ string from "1.25.1" to "2.0.0".

Activity

• No human activity has been recorded for this pull request.

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[gemini-code-assist]

Code Review

This pull request prepares for the 2.0.0 release by updating the version in the manifest and version file, and adding the corresponding changelog. The changes are appropriate for a release. I've found a minor typo in the changelog that should be corrected before merging.