[Somay-kousis]

Link to Issue or Description of Change

1. Link to an existing issue (if applicable):

• Closes: AgentTool's wrapped agent can't read the caller's temp: state #7595

2. Or, if no issue exists, describe the change:

Problem:

AgentTool.run_async copies the caller's state, temp: keys included, into create_session(state=...) for the nested runner. create_session drops temp: keys because they are never stored, so the wrapped agent can't see them. {temp:key?} in its instruction renders empty, {temp:key} raises KeyError, and its callbacks and tools read None.

Solution:

Split the temp: keys out of the copied state and pass them to the nested runner.run_async as state_delta. That's the public way to set temp: state for one invocation: append_event applies it to the in-memory session, then trims it from the stored event. Other keys still go through create_session as before, and nothing is persisted that wasn't before. Values that aren't JSON-serializable reach the wrapped agent unchanged, since they only live in memory.

Out of scope: temp: writes made inside the wrapped agent going back to the caller. Happy to look at that separately.

Testing Plan

Unit Tests:

• I have added or updated unit tests for my change.
• All unit tests pass locally.

test_agent_tool_reads_caller_temp_state in tests/unittests/tools/test_agent_tool.py, parametrized over each way the wrapped agent reads state: a required {temp:ticket} in its instruction, an optional {temp:ticket?}, its before_agent_callback, a tool it calls, a SequentialAgent wrapping an LlmAgent (the nested runner's legacy path), and an agent with input_schema. The caller sets a string temp: key, a temp: key holding a non-JSON-serializable object (checked by identity) and a plain key.

Before the fix:

message=f'Dynamic node {executed_name} failed',
E         google.adk.workflow._errors.DynamicNodeFailError: Dynamic node root_agent failed
ERROR    google_adk.google.adk.workflow._node_runner:_node_runner.py:163 Node execution failed with exception
ERROR    google_adk.google.adk.runners:runners.py:903 Root node tool_agent failed.
google.adk.workflow._errors.DynamicNodeFailError: Dynamic node tool_agent failed
ERROR    google_adk.google.adk.workflow._node_runner:_node_runner.py:163 Node execution failed with exception
google.adk.workflow._errors.DynamicNodeFailError: Dynamic node tool_agent failed
ERROR    google_adk.google.adk.runners:runners.py:903 Root node root_agent failed.
google.adk.workflow._errors.DynamicNodeFailError: Dynamic node root_agent failed
              message=f'Dynamic node {executed_name} failed',
E         google.adk.workflow._errors.DynamicNodeFailError: Dynamic node root_agent failed
ERROR    google_adk.google.adk.workflow._node_runner:_node_runner.py:163 Node execution failed with exception
ERROR    google_adk.google.adk.runners:runners.py:903 Root node root_agent failed.
google.adk.workflow._errors.DynamicNodeFailError: Dynamic node root_agent failed
              message=f'Dynamic node {executed_name} failed',
E         google.adk.workflow._errors.DynamicNodeFailError: Dynamic node root_agent failed
ERROR    google_adk.google.adk.workflow._node_runner:_node_runner.py:163 Node execution failed with exception
ERROR    google_adk.google.adk.runners:runners.py:903 Root node tool_agent failed.
google.adk.workflow._errors.DynamicNodeFailError: Dynamic node tool_agent failed
ERROR    google_adk.google.adk.workflow._node_runner:_node_runner.py:163 Node execution failed with exception
google.adk.workflow._errors.DynamicNodeFailError: Dynamic node tool_agent failed
ERROR    google_adk.google.adk.runners:runners.py:903 Root node root_agent failed.
google.adk.workflow._errors.DynamicNodeFailError: Dynamic node root_agent failed
FAILED tests/unittests/tools/test_agent_tool.py::test_agent_tool_reads_caller_temp_state[instruction]
FAILED tests/unittests/tools/test_agent_tool.py::test_agent_tool_reads_caller_temp_state[optional_instruction]
FAILED tests/unittests/tools/test_agent_tool.py::test_agent_tool_reads_caller_temp_state[callback]
FAILED tests/unittests/tools/test_agent_tool.py::test_agent_tool_reads_caller_temp_state[tool]
FAILED tests/unittests/tools/test_agent_tool.py::test_agent_tool_reads_caller_temp_state[sequential_agent]
FAILED tests/unittests/tools/test_agent_tool.py::test_agent_tool_reads_caller_temp_state[input_schema]
6 failed, 61 deselected in 10.40s

After the fix:

$ pytest tests/unittests/tools/test_agent_tool.py
67 passed in 6.86s

$ pytest tests/unittests/tools
3136 passed in 141.24s (0:02:21)

pyink --check and isort --check-only are clean on the changed files. mypy src/google/adk/tools/agent_tool.py reports the same one error as on main (AgentTool(agent=agent) in from_config, an existing BaseNode vs BaseAgent mismatch).

Manual End-to-End (E2E) Tests:

The script from the issue runs a coordinator LlmAgent with a tool that sets temp:ticket and an AgentTool specialist, on InMemoryRunner with fake models.

Before:

specialist instruction 'Ticket: {temp:ticket?}'
  coordinator saw: ['Ticket: ', 'Ticket: T-42', 'Ticket: T-42']
  specialist saw:  ['Ticket: ']
specialist instruction 'Ticket: {temp:ticket}'
  coordinator saw: ['Ticket: ', 'Ticket: T-42']
  specialist saw:  []
  run raised:      KeyError: "Context variable not found: `temp:ticket` in agent 'specialist'."

After:

specialist instruction 'Ticket: {temp:ticket?}'
  coordinator saw: ['Ticket: ', 'Ticket: T-42', 'Ticket: T-42']
  specialist saw:  ['Ticket: T-42']
specialist instruction 'Ticket: {temp:ticket}'
  coordinator saw: ['Ticket: ', 'Ticket: T-42', 'Ticket: T-42']
  specialist saw:  ['Ticket: T-42']

Checklist

• I have read the CONTRIBUTING.md document.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.
• I have manually tested my changes end-to-end.
• Any dependent changes have been merged and published in downstream modules.

Additional context

Open PRs touching agent_tool.py: #6020, #7045, #7249 and #7401. None changes how the caller's state reaches the nested session. #7045 re-indents the event loop, so one of the two may need a small rebase.

[adk-bot]

Thank you @Somay-kousis for your contribution! 🎉

Your changes have been successfully imported and merged via Copybara in commit 12c7bed.

Closing this PR as the changes are now in the main branch.