Shangjie Chen

refactor(a2a): relocate RemoteA2aAgent implementation and tests to a2a Move the core implementation of RemoteA2aAgent to google.adk.a2a.agent._remote_a2a_agent and export it from google.adk.a2a.agent. Retain a backward-compatible re-export shim in google.adk.agents.remote_a2a_agent. Migrate unit tests to tests/unittests/a2a/agent/ and update CI workflows and OWNERS. Co-authored-by: Shangjie Chen <deanchen@google.com> PiperOrigin-RevId: 981955554

refactor: Decompose functions.py into internal modular components (_tool_error_handler, _tool_caller, _batch_tool_executor) and deduplicate single-call async and live tool execution pipelines Co-authored-by: Shangjie Chen <deanchen@google.com> PiperOrigin-RevId: 976053981

fix(callables): extract unified CallableSpec and resolve doc and unwrap edge cases Unify callable introspection, docstring resolution, signature analysis, and type hint caching between FunctionTool and FunctionNode into a shared helper module adk/utils/_callable_utils.py, and place tool argument preprocessing in _schema_utils.py. Key changes: - Add `_callable_utils.py` defining `unwrap_callable`, `get_type_hints_cached`, and `CallableSpec` strictly focused on callable introspection and signature analysis. - Place tool argument preprocessing logic (`preprocess_args`) in `_schema_utils.py`. - Refactor `FunctionTool` to leverage `CallableSpec` for docstring resolution, signature analysis, and type hint caching, and `_schema_utils.preprocess_args` for model coercion. - Refactor `FunctionNode` to use `CallableSpec` for docstring, signature, type hints, and context parameter detection, and cache `spec.unwrapped_func`. - Fix `FunctionTool` description fallback to empty string for undocumented callables whose wrapper docstrings match default object/routine docstrings. - Fix unwrapping loops and signature introspection for builtin functions like `min`, gracefully handling signature-less callables in `FunctionTool.run_async`. - Robust type hint unwrapping: unwrapping `functools.partial` in `CallableSpec` enables resolving annotations under `from __future__ import annotations`, consistently activating Pydantic model coercion in `preprocess_args` where `typing.get_type_hints` previously failed with `TypeError`. - Add comprehensive unit tests in `tests/unittests/utils/test_callable_utils.py` and `tests/unittests/utils/test_schema_utils.py`. Co-authored-by: Shangjie Chen <deanchen@google.com> PiperOrigin-RevId: 975495673

fix: Restore `invocation_context.branch` from session history when executing a non-root agent node or resuming a sub-agent in `Runner` Any event the node authored is eligible, including a plain text turn, which is all a non-resumable sub-agent may leave behind. Tool messages are excluded: a tool's user-facing message is authored under the agent's name and carries the agent's node path, but is published on `<tool>@<function_call_id>`, so a branch whose trailing id matches a function call in the session is skipped. Nodes are matched by static node path (run ids stripped), falling back to author/name for path-less legacy events, disambiguating sub-agents that share a name. At the resume sites the scan is scoped to the invocation being resumed; the new-invocation and live paths use the most recent matching event. This supersedes the earlier (unsubmitted) cl/944151553, whose path-matching and invocation-scoping approach is folded in here. Co-authored-by: Shangjie Chen <deanchen@google.com> PiperOrigin-RevId: 970044047

feat: add optional abort_signal support to Runner, Workflow, and Nodes Support passing an asyncio.Event abort_signal to Runner.run_async to terminate agent and graph workflow execution loops early upon client disconnect or manual stop events. Closes #4796 Co-authored-by: Shangjie Chen <deanchen@google.com> PiperOrigin-RevId: 989843613

refactor(flows): relocate context and history processing into flows/llm_flows/context Move conversation history assembly, events compaction, context caching, and interactions API processing into a dedicated context/ subpackage under flows/llm_flows/. - Create flows/llm_flows/context/ containing _contents.py, _compaction.py, _cache.py, and _interactions.py. - Retain backward-compatibility shims at the original module paths (contents.py, compaction.py, _content_compaction.py, context_cache_processor.py, interactions_processor.py) with explicit symbol re-exports. - Relocate unit tests to tests/unittests/flows/llm_flows/context/ and add tests/unittests/flows/llm_flows/test_context_shims.py to verify re-exports. Co-authored-by: Shangjie Chen <deanchen@google.com> PiperOrigin-RevId: 982745684

refactor: map YAML agent configs onto agent classes by reflection Each agent class carried its own `_parse_config`, so every config field had to be wired up by hand in the class that consumed it, and a field added to one class was invisible to the others. `_AgentConfigMapper` derives the mapping from the target class instead: it reads the field annotations and resolves each YAML value to whatever that field expects -- callbacks, schemas, tools, sub-agents, models, and `*_code` references. With the mapper deriving all of that, the hand-written parsers on `LlmAgent` and `LoopAgent` have nothing left to add, and go away along with `LlmAgent._resolve_tools`. Existing 1.x configs load unchanged, a subclass overriding `_parse_config` still gets the last word on its kwargs, and the module denylist still gates every code reference. One capability is new: `agent_class` now also names `Workflow` and `FunctionNode`, which head rejected with "Invalid fully qualified name". Reflection maps onto any node class, not just the agent classes that shipped a parser, so restricting it to the latter would have been an extra rule rather than a simpler one. The graph syntax those nodes need is a follow-up. Co-authored-by: Shangjie Chen <deanchen@google.com> PiperOrigin-RevId: 972780349

feat: Implement Workflow as Tool core feature Introduce NodeTool, allowing individual Nodes and entire Workflows to be wrapped and executed as standard ADK Tools. This PR implements the core, single-turn execution capability: - Support auto-wrapping of BaseNode (Workflows) directly in Agent.tools. - Wrapping synchronous and asynchronous function nodes as NodeTools. - Providing a complete sample workflow demonstrating how to run a workflow as a tool. Resumption and multi-turn nested HITL support are skipped in this PR and will be fully enabled in the later PR. Co-authored-by: Shangjie Chen <deanchen@google.com> PiperOrigin-RevId: 943499058

fix: Support multi-turn nested HITL pause and resumption across workflows and agent tools Co-authored-by: Shangjie Chen <deanchen@google.com> PiperOrigin-RevId: 973238301

refactor: extract live flow logic from base_llm_flow into a dedicated module Co-authored-by: Shangjie Chen <deanchen@google.com> PiperOrigin-RevId: 975257909