From 488188cfdef3b6c37e01b1e2d8cc1392472e18dc Mon Sep 17 00:00:00 2001
From: Aarav Mittal <137450929+a2105z@users.noreply.github.com>
Date: Wed, 26 Aug 2026 07:56:22 -0500
Subject: [PATCH] fix: coerce callable AgentInfo.instruction for app-info

GET /apps/{app_name}/app-info assigned LlmAgent.instruction onto
AgentInfo.instruction (typed str). InstructionProvider callables
raised ValidationError. Coerce to a placeholder; do not resolve
providers (they can be async and need session state).

Fixes #6909
---
 src/google/adk/utils/agent_info.py       | 10 +++++
 tests/unittests/utils/test_agent_info.py | 55 ++++++++++++++++++++++++
 2 files changed, 65 insertions(+)

diff --git a/src/google/adk/utils/agent_info.py b/src/google/adk/utils/agent_info.py
index cfdf1024cc1..2fdcbfa81d3 100644
--- a/src/google/adk/utils/agent_info.py
+++ b/src/google/adk/utils/agent_info.py
@@ -33,6 +33,16 @@ class AgentInfo(pydantic.BaseModel):
   tools: list[types.Tool]
   sub_agents: list[str]
 
+  @pydantic.field_validator('instruction', mode='before')
+  @classmethod
+  def _coerce_callable_instruction(cls, value: object) -> object:
+    # LlmAgent.instruction is str | InstructionProvider. Providers may be
+    # async and may need session state, so app-info must not resolve them.
+    if callable(value):
+      name = getattr(value, '__name__', None) or type(value).__name__
+      return f'<InstructionProvider: {name}>'
+    return value
+
 
 async def get_tools_info(tools: list[ToolUnion]) -> list[Any]:
   """Returns the info for a given list of tools."""
diff --git a/tests/unittests/utils/test_agent_info.py b/tests/unittests/utils/test_agent_info.py
index f36c3e488e4..705d832723c 100644
--- a/tests/unittests/utils/test_agent_info.py
+++ b/tests/unittests/utils/test_agent_info.py
@@ -173,6 +173,61 @@ async def test_get_agents_dict_single_agent_has_no_sub_agents():
   assert agents['root'].tools == []
 
 
+@pytest.mark.asyncio
+async def test_get_agents_dict_coerces_callable_instruction():
+  def dynamic_instruction(ctx: ReadonlyContext) -> str:
+    raise RuntimeError('app-info must not resolve InstructionProvider')
+
+  agent = LlmAgent(
+      name='dyn',
+      description='Agent with a dynamic (callable) instruction.',
+      instruction=dynamic_instruction,
+  )
+
+  agents = await get_agents_dict(agent)
+
+  assert agents['dyn'].instruction == (
+      '<InstructionProvider: dynamic_instruction>'
+  )
+
+
+@pytest.mark.asyncio
+async def test_get_agents_dict_coerces_async_and_subagent_callables():
+  async def async_instruction(ctx: ReadonlyContext) -> str:
+    return 'async'
+
+  def child_instruction(ctx: ReadonlyContext) -> str:
+    return 'child'
+
+  child = LlmAgent(name='child', instruction=child_instruction)
+  root = LlmAgent(
+      name='root', instruction=async_instruction, sub_agents=[child]
+  )
+
+  agents = await get_agents_dict(root)
+
+  assert agents['root'].instruction == (
+      '<InstructionProvider: async_instruction>'
+  )
+  assert agents['child'].instruction == (
+      '<InstructionProvider: child_instruction>'
+  )
+
+
+@pytest.mark.asyncio
+async def test_get_agents_dict_coerces_instruction_provider_instance():
+  class Persona:
+
+    def __call__(self, ctx: ReadonlyContext) -> str:
+      return 'persona'
+
+  agent = LlmAgent(name='dyn', instruction=Persona())
+
+  agents = await get_agents_dict(agent)
+
+  assert agents['dyn'].instruction == '<InstructionProvider: Persona>'
+
+
 @pytest.mark.asyncio
 async def test_get_agents_dict_includes_transitively_nested_agents():
   grandchild = LlmAgent(name='grandchild')