what now

docs/wf_mcp_capability_sources.md

@@ -198,6 +198,9 @@ The code now has the first capability-source layer in place.
   Python callables. Inventory exposes `NodeSpecInventory` contracts instead:
   names, descriptions, outcomes, schemas, and execution flags, but never the
   wrapped function object itself.
+- Reducer inventory follows the same rule: executable reducer definitions stay
+  private, while `ReducerInventory` exposes only reducer names, descriptions,
+  and config schemas.
 - `WfMcpService.capability_sources` is the canonical in-memory registry.
 - Planner node lookup reads `CapabilitySource.capabilities.node_specs`
   directly; the old `SpecSource` compatibility layer has been removed.

src/wf_platform/__init__.py

@@ -4,6 +4,7 @@ from .sources import (
     CapabilityBuckets,
     CapabilitySource,
     NodeSpecInventory,
+    ReducerInventory,
     SourceCapabilityInventory,
     SourceInventory,
     SourceKind,
@@ -19,6 +20,7 @@ __all__ = [
     "CapabilitySource",
     "CapabilityRef",
     "NodeSpecInventory",
+    "ReducerInventory",
     "SourceCapabilityInventory",
     "SourceInventory",
     "SourceKind",

src/wf_platform/sources.py

@@ -55,6 +55,14 @@ class NodeSpecInventory(BaseModel):
     accepts_context: bool
 
 
+class ReducerInventory(BaseModel):
+    """Serializable public contract for one pure reducer."""
+
+    name: str
+    description: str | None = None
+    config_schema: JsonObject
+
+
 class SourceCapabilityInventory(BaseModel):
     """Serializable names owned by one source, grouped by capability kind."""
 
@@ -62,6 +70,7 @@ class SourceCapabilityInventory(BaseModel):
     node_specs: tuple[str, ...] = ()
     node_spec_details: tuple[NodeSpecInventory, ...] = ()
     reducers: tuple[str, ...] = ()
+    reducer_details: tuple[ReducerInventory, ...] = ()
     prompts: tuple[str, ...] = ()
     resources: tuple[str, ...] = ()
 
@@ -148,6 +157,17 @@ class CapabilitySource:
                     )
                 ),
                 reducers=tuple(sorted(self.capabilities.reducers)),
+                reducer_details=tuple(
+                    ReducerInventory(
+                        name=reducer.name,
+                        description=reducer.description,
+                        config_schema=reducer.config_schema,
+                    )
+                    for reducer in sorted(
+                        self.capabilities.reducers.values(),
+                        key=lambda reducer: reducer.name,
+                    )
+                ),
                 prompts=tuple(sorted(self.capabilities.prompts)),
                 resources=tuple(sorted(self.capabilities.resources)),
             ),

tests/platform/test_inventory.py

@@ -3,7 +3,13 @@ from __future__ import annotations
 from pydantic import BaseModel, Field
 
 from wf_authoring import node
-from wf_platform import CapabilityBuckets, CapabilitySource, NodeSpecInventory
+from wf_core import ReducerSpec
+from wf_platform import (
+    CapabilityBuckets,
+    CapabilitySource,
+    NodeSpecInventory,
+    ReducerInventory,
+)
 
 
 class EchoInput(BaseModel):
@@ -37,3 +43,26 @@ def test_source_inventory_exposes_serializable_node_spec_details() -> None:
     assert detail.outcomes == ("ok",)
     assert detail.input_schema["properties"]["text"]["description"] == "Text to echo."
     assert "fn" not in dumped["capabilities"]["node_spec_details"][0]
+
+
+def test_source_inventory_exposes_serializable_reducer_details() -> None:
+    source = CapabilitySource(
+        id="wf.std",
+        kind="system",
+        capabilities=CapabilityBuckets(
+            reducers={
+                "wf.std.max": ReducerSpec(
+                    name="wf.std.max",
+                    description="Keep the greater value.",
+                    config_schema={"type": "object", "properties": {}},
+                )
+            }
+        ),
+    )
+
+    detail = source.as_inventory().capabilities.reducer_details[0]
+
+    assert isinstance(detail, ReducerInventory)
+    assert detail.name == "wf.std.max"
+    assert detail.description == "Keep the greater value."
+    assert detail.config_schema == {"type": "object", "properties": {}}