CHANGELOG.md

@@ -16,6 +16,12 @@ The format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 
 ### Added
 
+- **TDD: MCPToolAdapter.infer_resource_slots() TypeError with null properties** (#10470):
+  Added a TDD issue-capture Behave scenario that reproduces the bug where
+  `MCPToolAdapter.infer_resource_slots()` raises `TypeError` when the input schema
+  contains `{"properties": None}`. The test is tagged `@tdd_expected_fail` and will
+  pass (by inversion) until the underlying bug is fixed.
+
 - **Architecture Pool Supervisor Milestone Assignment** (#7521): Added a "PR Workflow
   for Major Changes" section to the `architecture-pool-supervisor` agent definition
   documenting the milestone assignment step for spec PRs. The agent now has

features/steps/tdd_mcp_infer_resource_slots_null_properties_steps.py

@@ -0,0 +1,60 @@
+"""Step definitions for features/tdd_mcp_infer_resource_slots_null_properties.feature.
+
+TDD issue-capture scenario for #10470: MCPToolAdapter.infer_resource_slots()
+raises TypeError when the input schema has a null "properties" value.
+
+The bug: input_schema.get("properties", {}) returns None (not {}) when the
+key exists with a null value, causing TypeError on iteration.
+"""
+
+from __future__ import annotations
+
+from behave import given, then, when
+from behave.runner import Context
+
+from cleveragents.mcp.adapter import MCPToolAdapter
+
+
+@given("an MCP tool input schema where properties key is null")
+def step_given_null_properties_schema(context: Context) -> None:
+    """Set up an input schema where 'properties' key exists but has a null value."""
+    context.mcp_tool_name = "test_tool"
+    context.mcp_input_schema = {"properties": None}
+    context.infer_type_error = None
+    context.inferred_slots_result = None
+
+
+@when("I call infer_resource_slots with the null properties schema")
+def step_when_infer_slots_null_properties(context: Context) -> None:
+    """Call infer_resource_slots() and capture any TypeError raised."""
+    try:
+        context.inferred_slots_result = MCPToolAdapter.infer_resource_slots(
+            context.mcp_tool_name,
+            context.mcp_input_schema,
+        )
+    except TypeError as exc:
+        context.infer_type_error = exc
+
+
+@then("no TypeError should have been raised during slot inference")
+def step_then_no_type_error(context: Context) -> None:
+    """Assert that no TypeError was raised during infer_resource_slots()."""
+    assert context.infer_type_error is None, (
+        f"Expected no TypeError, but got: {context.infer_type_error!r}\n"
+        "Bug: infer_resource_slots() raises TypeError when 'properties' is None. "
+        "Fix: use `input_schema.get('properties') or {}` instead of "
+        "`input_schema.get('properties', {})`."
+    )
+
+
+@then("the inferred slots result should be an empty list")
+def step_then_slots_empty_list(context: Context) -> None:
+    """Assert that the result of infer_resource_slots() is an empty list."""
+    result = context.inferred_slots_result
+    assert result is not None, (
+        "inferred_slots_result is None — infer_resource_slots() likely raised "
+        "an exception before returning."
+    )
+    assert result == [], (
+        f"Expected infer_resource_slots() to return [], got: {result!r}"
+    )

features/tdd_mcp_infer_resource_slots_null_properties.feature

@@ -0,0 +1,12 @@
+@tdd_issue @tdd_issue_10470
+Feature: TDD Issue #10470 — MCPToolAdapter.infer_resource_slots() raises TypeError when properties is null
+  MCPToolAdapter.infer_resource_slots() uses input_schema.get("properties", {}) to retrieve
+  the properties dict. When the key exists but has a null value ({"properties": None}),
+  dict.get() returns None instead of the default {}, causing a TypeError when iterating.
+
+  @tdd_expected_fail
+  Scenario: infer_resource_slots() with null properties does not raise TypeError
+    Given an MCP tool input schema where properties key is null
+    When I call infer_resource_slots with the null properties schema
+    Then no TypeError should have been raised during slot inference
+    And the inferred slots result should be an empty list