helper to specifially rewrite proxied tool answer

docs/mcp_protocol_proxy_inventory.md

@@ -100,6 +100,10 @@ Tool simulate-research-query requires task augmentation (taskSupport: 'required'
   templates.
 - Tool-result resource links: incomplete; embedded resource URIs need explicit
   rewrite or a documented limitation.
+- `wf_mcp.proxy_results` now contains pure typed helpers for rewriting
+  `mcp.types.ResourceLink` content inside `mcp.types.CallToolResult`. These
+  helpers are not wired into the FastMCP proxy runtime yet because FastMCP does
+  not currently expose a result-transform hook.
 - Session resources: unresolved; needs a focused test because session affinity
   may matter.
 - Tasks: unsupported; task-required tools should remain clearly diagnosed until

src/wf_mcp/proxy_results/__init__.py

@@ -0,0 +1,11 @@
+from .resource_links import (
+    ResourceUriRewriter,
+    rewrite_call_tool_result_resource_links,
+    rewrite_resource_link_content,
+)
+
+__all__ = [
+    "ResourceUriRewriter",
+    "rewrite_call_tool_result_resource_links",
+    "rewrite_resource_link_content",
+]

src/wf_mcp/proxy_results/resource_links.py

@@ -0,0 +1,37 @@
+from __future__ import annotations
+
+from collections.abc import Callable
+
+import mcp.types as mcp_types
+
+ResourceUriRewriter = Callable[[str], str]
+
+
+def rewrite_resource_link_content(
+    content: mcp_types.ContentBlock,
+    rewrite_uri: ResourceUriRewriter,
+) -> mcp_types.ContentBlock:
+    """Return content with ResourceLink URI rewritten through a proxy mapper.
+
+    FastMCP's Namespace transform rewrites listed resource URIs, but tool-call
+    results can also contain typed ResourceLink content. This helper is pure and
+    uses the official MCP models so it can be reused by a future proxy hook.
+    """
+    if not isinstance(content, mcp_types.ResourceLink):
+        return content
+    return content.model_copy(update={"uri": rewrite_uri(str(content.uri))})
+
+
+def rewrite_call_tool_result_resource_links(
+    result: mcp_types.CallToolResult,
+    rewrite_uri: ResourceUriRewriter,
+) -> mcp_types.CallToolResult:
+    """Return a copy of a tool result with ResourceLink content URIs rewritten."""
+    return result.model_copy(
+        update={
+            "content": [
+                rewrite_resource_link_content(content, rewrite_uri)
+                for content in result.content
+            ]
+        }
+    )

src/wf_mcp/transparent_proxy/admin.py

@@ -145,4 +145,3 @@ async def _send_reload_notifications(ctx: Context, result: ProxyReloadResult) ->
     sink = FastMcpContextNotificationSink(ctx)
     for event in reload_change_events(result):
         await sink.send_event(event)
-

tests/wf_mcp/test_notifications.py

@@ -38,7 +38,9 @@ def test_maps_capability_change_events_to_mcp_list_changed_notifications() -> No
         resource_notifications[0].root,
         mcp_types.ResourceListChangedNotification,
     )
-    assert resource_notifications[0].root.method == "notifications/resources/list_changed"
+    assert (
+        resource_notifications[0].root.method == "notifications/resources/list_changed"
+    )
     assert isinstance(
         prompt_notifications[0].root,
         mcp_types.PromptListChangedNotification,
@@ -75,7 +77,9 @@ def test_fastmcp_context_notification_sink_sends_projected_notifications() -> No
         await sink.send_event(
             make_event("resources_changed", connection_id="demo.personal")
         )
-        await sink.send_event(make_event("workflow_artifact_saved", workflow_name="demo"))
+        await sink.send_event(
+            make_event("workflow_artifact_saved", workflow_name="demo")
+        )
 
     asyncio.run(run())
 

tests/wf_mcp/test_proxy_results.py

@@ -0,0 +1,75 @@
+from __future__ import annotations
+
+import mcp.types as mcp_types
+
+from wf_mcp.proxy_results import (
+    rewrite_call_tool_result_resource_links,
+    rewrite_resource_link_content,
+)
+
+
+def test_rewrites_resource_link_content_with_official_mcp_type() -> None:
+    content = _resource_link("demo://resource/dynamic/text/2")
+
+    rewritten = rewrite_resource_link_content(
+        content,
+        lambda uri: uri.replace("demo://", "demo://everything.default/"),
+    )
+
+    assert isinstance(rewritten, mcp_types.ResourceLink)
+    assert str(rewritten.uri) == "demo://everything.default/resource/dynamic/text/2"
+    assert rewritten.name == "dynamic-text"
+    assert rewritten.mimeType == "text/plain"
+    assert str(content.uri) == "demo://resource/dynamic/text/2"
+
+
+def test_non_resource_link_content_is_returned_unchanged() -> None:
+    content = mcp_types.TextContent(type="text", text="ordinary text")
+
+    rewritten = rewrite_resource_link_content(
+        content,
+        lambda uri: f"rewritten:{uri}",
+    )
+
+    assert rewritten is content
+
+
+def test_rewrites_resource_links_inside_call_tool_result() -> None:
+    result = mcp_types.CallToolResult(
+        content=[
+            mcp_types.TextContent(type="text", text="see linked resource"),
+            _resource_link("demo://resource/dynamic/text/2"),
+        ],
+        structuredContent={"ok": True},
+        _meta={"source": "fixture"},
+    )
+
+    rewritten = rewrite_call_tool_result_resource_links(
+        result,
+        lambda uri: uri.replace("demo://", "demo://everything.default/"),
+    )
+
+    assert rewritten is not result
+    assert rewritten.structuredContent == {"ok": True}
+    assert rewritten.meta == {"source": "fixture"}
+    assert rewritten.content[0] is result.content[0]
+    rewritten_link = rewritten.content[1]
+    original_link = result.content[1]
+    assert isinstance(rewritten_link, mcp_types.ResourceLink)
+    assert isinstance(original_link, mcp_types.ResourceLink)
+    assert str(rewritten_link.uri) == (
+        "demo://everything.default/resource/dynamic/text/2"
+    )
+    assert str(original_link.uri) == "demo://resource/dynamic/text/2"
+
+
+def _resource_link(uri: str) -> mcp_types.ResourceLink:
+    """Build ResourceLink through validation because Pydantic accepts URI strings."""
+    return mcp_types.ResourceLink.model_validate(
+        {
+            "type": "resource_link",
+            "name": "dynamic-text",
+            "uri": uri,
+            "mimeType": "text/plain",
+        }
+    )

tests/wf_mcp/test_transparent_proxy.py

@@ -553,9 +553,7 @@ def test_transparent_proxy_runtime_reload_publishes_local_change_events() -> Non
 
     events = sink.list_events()[initial_event_count:]
     event_kinds = [event.kind for event in events]
-    catalog_changed = [
+    catalog_changed = [event for event in events if event.kind == "catalog_changed"]
-        event for event in events if event.kind == "catalog_changed"
-    ]
     assert result["reloaded"] is True
     assert "tools_changed" in event_kinds
     assert "resources_changed" in event_kinds