docs: migrate example field reads to snake_case for MCP SDK v2

docs/clients/client.mdx

@@ -135,7 +135,7 @@ def greet(name: str) -> str:
 
 async with Client(mcp) as client:
     # Initialization already happened automatically
-    print(f"Server: {client.initialize_result.serverInfo.name}")
+    print(f"Server: {client.initialize_result.server_info.name}")
     print(f"Instructions: {client.initialize_result.instructions}")
     print(f"Capabilities: {client.initialize_result.capabilities.tools}")
 ```
@@ -154,7 +154,7 @@ async with client:
 
     # Initialize manually with custom timeout
     result = await client.initialize(timeout=10.0)
-    print(f"Server: {result.serverInfo.name}")
+    print(f"Server: {result.server_info.name}")
 
     # Now ready for operations
     tools = await client.list_tools()

docs/clients/elicitation.mdx

@@ -69,7 +69,7 @@ The handler receives four parameters:
 </ResponseField>
 
 <ResponseField name="params" type="ElicitRequestParams">
-  The original MCP elicitation parameters, including the raw JSON schema in `params.requestedSchema`
+  The original MCP elicitation parameters, including the raw JSON schema in `params.requested_schema`
 </ResponseField>
 
 <ResponseField name="context" type="RequestContext">

docs/clients/resources.mdx

@@ -53,7 +53,7 @@ async with client:
     for item in content:
         if hasattr(item, 'text'):
             print(f"Text content: {item.text}")
-            print(f"MIME type: {item.mimeType}")
+            print(f"MIME type: {item.mime_type}")
 ```
 
 Binary resources include images, PDFs, and other non-text data:
@@ -65,7 +65,7 @@ async with client:
     for item in content:
         if hasattr(item, 'blob'):
             print(f"Binary content: {len(item.blob)} bytes")
-            print(f"MIME type: {item.mimeType}")
+            print(f"MIME type: {item.mime_type}")
 
             # Save to file
             with open("downloaded_logo.png", "wb") as f:

docs/clients/sampling.mdx

@@ -42,7 +42,7 @@ async def sampling_handler(
         conversation.append(f"{message.role}: {content}")
 
     # Use the system prompt if provided
-    system_prompt = params.systemPrompt or "You are a helpful assistant."
+    system_prompt = params.system_prompt or "You are a helpful assistant."
 
     # Integrate with your LLM service here
     return "Generated response based on the messages"

docs/clients/tools.mdx

@@ -175,7 +175,7 @@ async with client:
     result = await client.call_tool_mcp("my_tool", {"param": "value"})
     # result -> fastmcp.types.CallToolResult
 
-    if result.isError:
+    if result.is_error:
         print(f"Tool failed: {result.content}")
     else:
         print(f"Tool succeeded: {result.content}")

docs/development/tests.mdx

@@ -228,7 +228,7 @@ async def test_tool_schema_generation():
         return {"amount": amount, "tax": amount * rate, "total": amount * (1 + rate)}
     
     tools = mcp.list_tools()
-    schema = tools[0].inputSchema
+    schema = tools[0].input_schema
     
     # First run: snapshot() is empty, gets auto-populated
     # Subsequent runs: compares against stored snapshot

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

@@ -1205,8 +1205,8 @@ When `list_page_size` is set, `tools/list`, `resources/list`, `resources/templat
 ```python
 async with Client(server) as client:
     result = await client.list_tools_mcp()
-    while result.nextCursor:
-        result = await client.list_tools_mcp(cursor=result.nextCursor)
+    while result.next_cursor:
+        result = await client.list_tools_mcp(cursor=result.next_cursor)
 ```
 
 Documentation: [Pagination](/servers/pagination)

docs/servers/icons.mdx

@@ -19,7 +19,7 @@ from fastmcp.types import Icon
 
 icon = Icon(
     src="https://example.com/icon.png",
-    mimeType="image/png",
+    mime_type="image/png",
     sizes=["48x48"]
 )
 ```
@@ -27,7 +27,7 @@ icon = Icon(
 The fields serve different purposes:
 
 - **src**: URL or data URI pointing to the icon image
-- **mimeType** (optional): MIME type of the image (e.g., "image/png", "image/svg+xml")
+- **mime_type** (optional): MIME type of the image (e.g., "image/png", "image/svg+xml")
 - **sizes** (optional): Array of size descriptors (e.g., ["48x48"], ["any"])
 
 ## Server Icons
@@ -44,12 +44,12 @@ mcp = FastMCP(
     icons=[
         Icon(
             src="https://weather.example.com/icon-48.png",
-            mimeType="image/png",
+            mime_type="image/png",
             sizes=["48x48"]
         ),
         Icon(
             src="https://weather.example.com/icon-96.png",
-            mimeType="image/png",
+            mime_type="image/png",
             sizes=["96x96"]
         ),
     ]
@@ -121,7 +121,7 @@ from fastmcp.utilities.types import Image
 # SVG icon as data URI
 svg_icon = Icon(
     src="data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSIyNCIgaGVpZ2h0PSIyNCI+PHBhdGggZD0iTTEyIDJDNi40OCAyIDIgNi40OCAyIDEyczQuNDggMTAgMTAgMTAgMTAtNC40OCAxMC0xMFMxNy41MiAyIDEyIDJ6Ii8+PC9zdmc+",
-    mimeType="image/svg+xml"
+    mime_type="image/svg+xml"
 )
 
 @mcp.tool(icons=[svg_icon])

docs/servers/pagination.mdx

@@ -34,7 +34,7 @@ def analyze(data: str) -> dict:
 # ... many more tools, resources, prompts
 ```
 
-When `list_page_size` is configured, the `tools/list`, `resources/list`, `resources/templates/list`, and `prompts/list` endpoints all paginate their responses. Each response includes a `nextCursor` field when more results exist, which clients use to fetch subsequent pages.
+When `list_page_size` is configured, the `tools/list`, `resources/list`, `resources/templates/list`, and `prompts/list` endpoints all paginate their responses. Each response includes a `next_cursor` field when more results exist, which clients use to fetch subsequent pages.
 
 ### Cursor Format
 
@@ -66,12 +66,12 @@ async with Client(server) as client:
     print(f"Page 1: {len(result.tools)} tools")
 
     # Continue fetching while more pages exist
-    while result.nextCursor:
-        result = await client.list_tools_mcp(cursor=result.nextCursor)
+    while result.next_cursor:
+        result = await client.list_tools_mcp(cursor=result.next_cursor)
         print(f"Next page: {len(result.tools)} tools")
 ```
 
-The `_mcp` methods return the raw MCP protocol objects, which include both the items and the `nextCursor` for the next page. When `nextCursor` is `None`, you've reached the end of the result set.
+The `_mcp` methods return the raw MCP protocol objects, which include both the items and the `next_cursor` for the next page. When `next_cursor` is `None`, you've reached the end of the result set.
 
 All four list operations support manual pagination:
 

docs/servers/sampling.mdx

@@ -443,7 +443,7 @@ async def research(question: str, ctx: Context) -> str:
             tool_results.append(
                 ToolResultContent(
                     type="tool_result",
-                    toolUseId=call.id,
+                    tool_use_id=call.id,
                     content=[TextContent(type="text", text=result)],
                 )
             )
@@ -452,14 +452,14 @@ async def research(question: str, ctx: Context) -> str:
         messages.append(SamplingMessage(role="user", content=tool_results))
 ```
 
-To report an error to the LLM, set `isError=True` on the tool result:
+To report an error to the LLM, set `is_error=True` on the tool result:
 
 ```python
 tool_result = ToolResultContent(
     type="tool_result",
-    toolUseId=call.id,
+    tool_use_id=call.id,
     content=[TextContent(type="text", text="Permission denied")],
-    isError=True,
+    is_error=True,
 )
 ```
 

docs/servers/tools.mdx

@@ -746,7 +746,7 @@ ToolResult(content="Hello, world!")
 # List of content blocks
 ToolResult(content=[
     TextContent(type="text", text="Result: 42"),
-    ImageContent(type="image", data="base64...", mimeType="image/png")
+    ImageContent(type="image", data="base64...", mime_type="image/png")
 ])
 ```