feat: Add mcp-session-id header to HTTP request trace attributes

Author: swcollard

.changesets/feat_trace_session_id.md

@@ -0,0 +1,3 @@
+### feat: Add mcp-session-id header to HTTP request trace attributes
+
+Includes the value of the [Mcp-Session-Id](https://modelcontextprotocol.io/specification/2025-06-18/basic/transports#session-management) HTTP header as an attribute of the trace for HTTP requests to the MCP Server

crates/apollo-mcp-server/src/server/states/starting.rs

@@ -222,6 +222,7 @@ impl Starting {
                                 "mcp_server",
                                 method = %request.method(),
                                 uri = %request.uri(),
+                                session_id = %request.headers().get("mcp-session-id").and_then(|v| v.to_str().ok()).unwrap_or("none"),
                                 status_code = tracing::field::Empty,
                             )
                         })

crates/apollo-mcp-server/src/telemetry_attributes.rs

@@ -29,6 +29,9 @@ impl TelemetryAttribute {
             TelemetryAttribute::ClientVersion => {
                 Key::from_static_str(TelemetryAttribute::ClientVersion.as_str())
             }
+            TelemetryAttribute::SessionId => {
+                Key::from_static_str(TelemetryAttribute::SessionId.as_str())
+            }
         }
     }
 

crates/apollo-mcp-server/telemetry.toml

@@ -7,6 +7,7 @@ success = "Sucess flag indicator"
 raw_operation = "Graphql operation text and metadata used for Tool generation"
 client_name = "The client name that initializes with the MCP Server"
 client_version = "The client version that initializes with the MCP Server"
+session_id = "The value of the Mcp-Session-Id header in the HTTP request"
 
 [metrics.apollo.mcp]
 "initialize.count" = "Number of times initialize has been called"