Add transform system for modifying components in provider chains

docs/development/upgrade-guide.mdx

@@ -21,7 +21,7 @@ FastMCP v3 introduces a unified provider architecture for sourcing components. A
 - **LocalProvider** stores decorator-registered components (`@mcp.tool`, etc.)
 - **FastMCPProvider** wraps another FastMCP server for composition
 - **ProxyProvider** connects to remote MCP servers
-- **TransformingProvider** adds namespacing and renaming
+- **Transforms** modify components (namespacing, renaming) via `add_transform()`
 
 See [Providers](/servers/providers/overview) for the complete documentation.
 

docs/development/v3-notes/v3-features.mdx

@@ -24,7 +24,7 @@ class Provider:
 Providers support:
 - **Lifecycle management**: `async def lifespan()` for setup/teardown
 - **Visibility control**: `enable()` / `disable()` with keys, tags, and allowlist mode
-- **Transformation chaining**: `provider.with_transforms(namespace=..., tool_renames=...)`
+- **Transform stacking**: `provider.add_transform(Namespace(...))`, `provider.add_transform(ToolTransform(...))`
 
 ### LocalProvider
 
@@ -91,27 +91,32 @@ def greet(name: str) -> str:
     return f"Hello, {name}!"
 
 # Mount with namespace
-main.add_provider(FastMCPProvider(sub).with_namespace("sub"))
+provider = FastMCPProvider(sub)
+provider.add_transform(Namespace("sub"))
+main.add_provider(provider)
 # Tool accessible as "sub_greet"
 ```
 
-### TransformingProvider
+### Transforms
 
-`TransformingProvider` (`src/fastmcp/server/providers/transforming.py`) wraps any provider to apply namespace prefixes and tool renames. Usually accessed via `provider.with_transforms()`.
+Transforms modify components (tools, resources, prompts) as they flow through the system. Available transforms:
+
+- `Namespace` - adds prefixes to names and path segments to URIs
+- `ToolTransform` - modifies tool schemas (rename, description, tags)
+- `Visibility` - filters components (internal, backs enable/disable API)
 
 ```python
-provider = SomeProvider().with_transforms(
-    namespace="api",
-    tool_renames={"verbose_tool_name": "short"}
-)
+from fastmcp.server.transforms import Namespace, ToolTransform
+from fastmcp.tools.tool_transform import ToolTransformConfig
+
+provider = SomeProvider()
+provider.add_transform(Namespace("api"))
+provider.add_transform(ToolTransform({
+    "api_verbose_tool_name": ToolTransformConfig(name="short")
+}))
 
 # Stacking composes transformations
-provider = (
-    SomeProvider()
-    .with_transforms(namespace="api")
-    .with_transforms(tool_renames={"api_foo": "bar"})
-)
-# "foo" → "api_foo" → "bar"
+# "foo" → "api_foo" (namespace) → could rename further with ToolTransform
 ```
 
 ---

docs/docs.json

@@ -20,10 +20,7 @@
     "primary": "#2d00f7"
   },
   "contextual": {
-    "options": [
-      "copy",
-      "view"
-    ]
+    "options": ["copy", "view"]
   },
   "description": "The fast, Pythonic way to build MCP servers and clients.",
   "errors": {
@@ -108,10 +105,10 @@
                 "icon": "layer-group",
                 "pages": [
                   "servers/providers/overview",
+                  "servers/providers/transforms",
                   "servers/providers/local",
                   "servers/providers/filesystem",
                   "servers/providers/mounting",
-                  "servers/providers/namespacing",
                   "servers/providers/proxy",
                   "servers/providers/custom"
                 ]
@@ -120,6 +117,7 @@
                 "group": "Features",
                 "icon": "stars",
                 "pages": [
+                  "servers/visibility",
                   "servers/tasks",
                   "servers/context",
                   "servers/elicitation",
@@ -162,10 +160,7 @@
               {
                 "group": "Essentials",
                 "icon": "cube",
-                "pages": [
-                  "clients/client",
-                  "clients/transports"
-                ]
+                "pages": ["clients/client", "clients/transports"]
               },
               {
                 "group": "Core Operations",
@@ -192,10 +187,7 @@
               {
                 "group": "Authentication",
                 "icon": "user-shield",
-                "pages": [
-                  "clients/auth/oauth",
-                  "clients/auth/bearer"
-                ]
+                "pages": ["clients/auth/oauth", "clients/auth/bearer"]
               }
             ]
           },
@@ -205,10 +197,7 @@
               {
                 "group": "Providers",
                 "icon": "globe",
-                "pages": [
-                  "integrations/fastapi",
-                  "integrations/openapi"
-                ]
+                "pages": ["integrations/fastapi", "integrations/openapi"]
               },
               {
                 "group": "Authentication",
@@ -262,7 +251,6 @@
           {
             "group": "Patterns",
             "pages": [
-              "patterns/tool-transformation",
               "patterns/decorating-methods",
               "patterns/cli",
               "patterns/contrib",
@@ -571,6 +559,14 @@
     {
       "destination": "/servers/providers/mounting",
       "source": "/servers/composition"
+    },
+    {
+      "destination": "/servers/providers/transforms",
+      "source": "/servers/providers/namespacing"
+    },
+    {
+      "destination": "/servers/providers/transforms",
+      "source": "/patterns/tool-transformation"
     }
   ],
   "search": {