refactor(mcp): match Python MCP client instrumentation exactly

Reverted enhancements to match the Python MCP client implementation
precisely. The Python client instrumentation does NOT set:
- TRACELOOP_WORKFLOW_NAME on any spans
- TRACELOOP_SPAN_KIND on generic method spans (only on tool calls)
- TRACELOOP_ENTITY_NAME on generic method spans (only on tool calls)

Changes:
1. Session span:
   - Use "session" string literal instead of enum
   - Remove TRACELOOP_WORKFLOW_NAME

2. Tool call spans:
   - Use "tool" string literal instead of enum
   - Keep TRACELOOP_ENTITY_NAME (tool name)
   - Remove TRACELOOP_WORKFLOW_NAME

3. Generic method spans (tools/list, resources/read, etc):
   - Remove TRACELOOP_SPAN_KIND
   - Remove TRACELOOP_ENTITY_NAME
   - Keep TRACELOOP_ENTITY_INPUT/OUTPUT

All 6 tests passing ✓
Sample app verified ✓

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: nirga

packages/instrumentation-mcp/src/instrumentation.ts

@@ -28,7 +28,6 @@ import {
 } from "@opentelemetry/instrumentation";
 import {
   SpanAttributes,
-  TraceloopSpanKindValues,
   CONTEXT_KEY_ALLOW_TRACE_CONTENT,
 } from "@traceloop/ai-semantic-conventions";
 import { McpInstrumentationConfig } from "./types";
@@ -247,23 +246,13 @@ export class McpInstrumentation extends InstrumentationBase {
 
       span.setAttribute(
         SpanAttributes.TRACELOOP_SPAN_KIND,
-        TraceloopSpanKindValues.SESSION,
+        "session",
       );
       span.setAttribute(
         SpanAttributes.TRACELOOP_ENTITY_NAME,
         "mcp.client.session",
       );
 
-      // Add client/server name as workflow name
-      // eslint-disable-next-line @typescript-eslint/no-explicit-any
-      const clientInfo = (this as any)._clientInfo;
-      if (clientInfo && clientInfo.name) {
-        span.setAttribute(
-          SpanAttributes.TRACELOOP_WORKFLOW_NAME,
-          `${clientInfo.name}.mcp`,
-        );
-      }
-
       // Create a context with this session span
       const sessionContext = trace.setSpan(context.active(), span);
 
@@ -332,20 +321,13 @@ export class McpInstrumentation extends InstrumentationBase {
       const method = request.method;
       const params = request.params;
 
-      // Determine span name and kind based on method
+      // Determine span name based on method
       let spanName: string;
-      let spanKind: string;
-      let entityName: string;
-
       if (method === "tools/call") {
         const toolName = (params as MCPToolCallParams)?.name || "unknown";
         spanName = `${toolName}.tool`;
-        entityName = toolName;
-        spanKind = TraceloopSpanKindValues.TOOL;
       } else {
         spanName = `${method}.mcp`;
-        entityName = method;
-        spanKind = TraceloopSpanKindValues.UNKNOWN;
       }
 
       // Use the stored session context as parent if available
@@ -360,21 +342,11 @@ export class McpInstrumentation extends InstrumentationBase {
         parentContext,
       );
 
-      span.setAttribute(SpanAttributes.TRACELOOP_SPAN_KIND, spanKind);
-      span.setAttribute(SpanAttributes.TRACELOOP_ENTITY_NAME, entityName);
-
-      // Add workflow name from client/server info (similar to Python implementation)
-      // eslint-disable-next-line @typescript-eslint/no-explicit-any
-      const clientInfo = (this as any)._clientInfo;
-      // eslint-disable-next-line @typescript-eslint/no-explicit-any
-      const serverInfo = (this as any).server?._serverInfo;
-
-      const info = clientInfo || serverInfo;
-      if (info && info.name) {
-        span.setAttribute(
-          SpanAttributes.TRACELOOP_WORKFLOW_NAME,
-          `${info.name}.mcp`,
-        );
+      // Only set span kind and entity name for tool calls (matching Python implementation)
+      if (method === "tools/call") {
+        const toolName = (params as MCPToolCallParams)?.name || "unknown";
+        span.setAttribute(SpanAttributes.TRACELOOP_SPAN_KIND, "tool");
+        span.setAttribute(SpanAttributes.TRACELOOP_ENTITY_NAME, toolName);
       }
 
       // Add input attributes if traceContent is enabled

packages/instrumentation-mcp/test/instrumentation.test.ts

@@ -248,16 +248,12 @@ describe("Test MCP instrumentation", function () {
     const sessionSpan = sessionSpans[0];
     assert.strictEqual(
       sessionSpan.attributes[SpanAttributes.TRACELOOP_SPAN_KIND],
-      TraceloopSpanKindValues.SESSION,
+      "session",
     );
     assert.strictEqual(
       sessionSpan.attributes[SpanAttributes.TRACELOOP_ENTITY_NAME],
       "mcp.client.session",
     );
-    assert.strictEqual(
-      sessionSpan.attributes[SpanAttributes.TRACELOOP_WORKFLOW_NAME],
-      "test-client.mcp",
-    );
   });
 
   it("should create tool call spans with correct attributes", async () => {
@@ -331,29 +327,20 @@ describe("Test MCP instrumentation", function () {
     const sessionSpan = sessionSpans[0];
     assert.strictEqual(
       sessionSpan.attributes[SpanAttributes.TRACELOOP_SPAN_KIND],
-      TraceloopSpanKindValues.SESSION,
-    );
-    assert.strictEqual(
-      sessionSpan.attributes[SpanAttributes.TRACELOOP_WORKFLOW_NAME],
-      "test-client.mcp",
+      "session",
     );
 
     // Verify tool span
     assert.ok(toolSpans.length > 0, "Should create tool span");
     const toolSpan = toolSpans[0];
     assert.strictEqual(
       toolSpan.attributes[SpanAttributes.TRACELOOP_SPAN_KIND],
-      TraceloopSpanKindValues.TOOL,
+      "tool",
     );
     assert.strictEqual(
       toolSpan.attributes[SpanAttributes.TRACELOOP_ENTITY_NAME],
       "test_tool",
     );
-    // Verify workflow name is also set on tool spans (matching Python implementation)
-    assert.strictEqual(
-      toolSpan.attributes[SpanAttributes.TRACELOOP_WORKFLOW_NAME],
-      "test-client.mcp",
-    );
 
     // Verify tool span has input/output (since traceContent is enabled by default)
     const input = JSON.parse(