docs(integrations): say that mcp records tool arguments and results by default

docs/integrations/(frameworks)/mcp.mdx

@@ -1,7 +1,7 @@
 ---
 title: Model Context Protocol
 description: Trace requests across official TypeScript MCP SDK v2 client and server transports.
-lastModified: 2026-10-18
+lastModified: 2026-11-10
 seo:
   title: "Model Context Protocol (MCP) Tracing"
   description: "Trace Model Context Protocol requests across client and server transports of the official TypeScript MCP SDK v2, with tool names, errors, and trace context."
@@ -97,6 +97,7 @@ Each JSON-RPC request makes a client span on the side that sends it and a server
 - The protocol version, and the session ID when the transport has one
 - The tool name for `tools/call`, the prompt name for `prompts/get`, and the resource URI for `resources/read`, `resources/subscribe`, and `resources/unsubscribe`
 - Errors: JSON-RPC error responses and tool results marked `isError`
+- The tool arguments and the tool result of `tools/call`, from version 0.3.0 (see [Control payload capture](#control-payload-capture))
 
 Both spans record the JSON-RPC error code. The client span is always marked as an error. The server span is not marked as an error when the code means the caller sent a bad request, such as a parse error, an unknown method, or invalid params.
 
@@ -108,29 +109,34 @@ Trace context travels in MCP request metadata by default, so the server span con
 
 - Notifications. They do not produce spans.
 - Metrics. The integration does not emit any.
-- Tool arguments and results, unless you turn on payload capture.
 
 ## Control payload capture
 
-Tool arguments and successful tool results are not captured by default. Turn them on for a transport only when that content is safe to send:
+From version 0.3.0, `tools/call` spans record the tool arguments and the tool result. This includes a result marked `isError`, whose content usually says why the tool failed. Earlier versions record them only with `capturePayloads: true`, and never record the content of a failed result.
+
+The core SDK's settings decide what reaches the span:
+
+- `captureInput: false` drops the arguments.
+- `captureOutput: false` drops the result.
+- `mask` and `maxAttributeLength` apply to both.
+
+To keep tool content out of one transport while the SDK captures other content, turn payload capture off:
 
 ```ts
 const transport = instrumentMcpTransport(mcpTransport, {
-  capturePayloads: true,
+  capturePayloads: false,
 });
 ```
 
-The core SDK's `captureInput`, `captureOutput`, `mask`, and `maxAttributeLength` settings still apply. `capturePayloads` lets tool content reach those controls; it does not override them. A failed tool result is marked as an error, but its content is not captured as output.
-
-With payload capture off, method names, tool and prompt names, resource URIs, request and session IDs, and error details are still recorded. Keep secrets out of those fields.
+Error codes and the JSON-RPC error message are recorded with every setting, and `captureOutput: false` and `mask` do not apply to them. Method names, tool and prompt names, resource URIs, and request and session IDs are also recorded with every setting. Keep secrets out of those fields.
 
 ## Options
 
 `instrumentMcpTransport(transport, options)` accepts:
 
 | Option | Type | Default | Description |
 | --- | --- | --- | --- |
-| `capturePayloads` | `boolean` | `false` | Capture tool arguments and successful tool results |
+| `capturePayloads` | `boolean` | `true` (`false` before 0.3.0) | Capture tool arguments and tool results |
 | `propagateBaggage` | `boolean` | `false` | Send and accept OpenTelemetry baggage in MCP request metadata |
 
 Configure the API key, service name, environment, and content controls with [`init()` options](/sdk/typescript#configure-init).