Merge remote-tracking branch 'origin/v2/fix/1909-salvage-malformed-list-items' into v2/fix/1909-salvage-malformed-list-items

clients/web/src/test/core/mcp/inspectorClient-initial-logging-era.test.ts

@@ -0,0 +1,127 @@
+import { describe, it, expect } from "vitest";
+import type { JSONRPCMessage, Transport } from "@modelcontextprotocol/client";
+import { InspectorClient } from "@inspector/core/mcp/inspectorClient.js";
+import {
+  MODERN_PROTOCOL_VERSION,
+  eraToVersionNegotiation,
+} from "@inspector/core/mcp/types.js";
+
+/**
+ * Regression coverage for #1990: the connect-time `initialLoggingLevel` must be
+ * gated on the negotiated era, not on the server capability alone.
+ *
+ * `logging/setLevel` is a legacy-era method, and the modern wire era rejects it
+ * outright ("Method 'logging/setLevel' is not supported by the negotiated
+ * protocol version"). Because the call sat in `connect()`'s post-handshake
+ * sequence, that rejection failed the *connection* — so the CLI (the one caller
+ * that passes `initialLoggingLevel`, hardcoded to "debug" in
+ * `clients/cli/src/cli.ts`) could not run *any* method against a modern server
+ * that advertised `logging`, logging-related or not.
+ *
+ * The two cases below are the era split: legacy still sends the request with the
+ * configured level, modern connects cleanly and never puts the method on the
+ * wire. The modern half asserts on the sent methods rather than on connect
+ * succeeding alone — a server that happens to answer the method would hide the
+ * regression behind a green connect.
+ *
+ * A fake transport carries both. The modern leg needs no `initialize` at all:
+ * the SDK negotiates with a `server/discover` probe and adopts that result's
+ * capabilities directly, which is also what lets one small class serve both eras
+ * by answering whichever handshake arrives.
+ */
+class CapabilityAdvertisingTransport implements Transport {
+  onmessage?: (message: JSONRPCMessage) => void;
+  onclose?: () => void;
+  onerror?: (error: Error) => void;
+
+  /** Every method this client put on the wire, in order. */
+  readonly sentMethods: string[] = [];
+
+  /** The params of the `logging/setLevel` request, if one was sent. */
+  loggingSetLevelParams?: Record<string, unknown>;
+
+  async start(): Promise<void> {}
+
+  async close(): Promise<void> {
+    this.onclose?.();
+  }
+
+  async send(message: JSONRPCMessage): Promise<void> {
+    if (!("method" in message)) return;
+    this.sentMethods.push(message.method);
+
+    // The modern era's handshake: one probe, answered with the capabilities the
+    // client then treats as the server's.
+    if (message.method === "server/discover" && "id" in message) {
+      this.reply(message.id, {
+        supportedVersions: [MODERN_PROTOCOL_VERSION],
+        capabilities: { logging: {} },
+      });
+      return;
+    }
+
+    // The legacy era's handshake.
+    if (message.method === "initialize" && "id" in message) {
+      const params = message.params as { protocolVersion: string };
+      this.reply(message.id, {
+        protocolVersion: params.protocolVersion,
+        capabilities: { logging: {} },
+        serverInfo: { name: "logging-server", version: "1.0.0" },
+      });
+      return;
+    }
+
+    if (message.method === "logging/setLevel" && "id" in message) {
+      this.loggingSetLevelParams = message.params as Record<string, unknown>;
+      this.reply(message.id, {});
+      return;
+    }
+  }
+
+  private reply(id: string | number, result: Record<string, unknown>): void {
+    // The SDK resolves the request from its own microtask; delivering
+    // synchronously from inside `send()` is the earliest any server could.
+    this.onmessage?.({ jsonrpc: "2.0", id, result });
+  }
+}
+
+async function connectWith(
+  era: "legacy" | "modern",
+): Promise<CapabilityAdvertisingTransport> {
+  const transport = new CapabilityAdvertisingTransport();
+  const client = new InspectorClient(
+    { type: "streamable-http", url: "https://mcp.example/mcp" },
+    {
+      environment: { transport: () => ({ transport }) },
+      versionNegotiation: eraToVersionNegotiation(era),
+      initialLoggingLevel: "debug",
+    },
+  );
+
+  await client.connect();
+  expect(client.getProtocolEra()).toBe(era);
+  await client.disconnect();
+
+  return transport;
+}
+
+describe("InspectorClient connect() initial logging level, by era (#1990)", () => {
+  it("sends logging/setLevel on a legacy connection", async () => {
+    const transport = await connectWith("legacy");
+
+    expect(transport.sentMethods).toContain("logging/setLevel");
+    expect(transport.loggingSetLevelParams).toMatchObject({ level: "debug" });
+  });
+
+  it("never sends logging/setLevel on a modern connection", async () => {
+    const transport = await connectWith("modern");
+
+    // Modern has no session-scoped level: the equivalent is the per-request
+    // `io.modelcontextprotocol/logLevel` `_meta` opt-in, driven by the
+    // `modernLogLevel` server setting rather than by `initialLoggingLevel`.
+    expect(transport.sentMethods).not.toContain("logging/setLevel");
+    // The server did advertise logging, so the capability check alone would
+    // have let the call through — the era gate is what stops it.
+    expect(transport.sentMethods).toContain("server/discover");
+  });
+});

core/mcp/inspectorClient.ts

@@ -1977,8 +1977,23 @@ export class InspectorClient extends InspectorClientEventTarget {
       // capabilities and wipe tools/prompts/resources to empty on every connect.
       await this.fetchServerInfo();
 
-      // Set initial logging level if configured and server supports it
+      // Set initial logging level if configured and server supports it.
-      if (this.initialLoggingLevel && this.capabilities?.logging) {
+      //
+      // Era-gated (#1990): `logging/setLevel` is a legacy-era method, and the
+      // modern wire era rejects it outright — so an unconditional call here
+      // failed the *connect* of every modern server advertising `logging`,
+      // taking down commands that have nothing to do with logging. Modern has
+      // no session-scoped level at all: the equivalent is the per-request
+      // `io.modelcontextprotocol/logLevel` `_meta` opt-in, which
+      // `modernLogLevel` already drives from the server settings (see
+      // {@link setModernLogLevel}). So the right behavior on modern is to skip
+      // this call rather than translate it — `initialLoggingLevel` names a
+      // mechanism that era does not have.
+      if (
+        this.initialLoggingLevel &&
+        this.capabilities?.logging &&
+        this.protocolEra !== "modern"
+      ) {
         await this.client.setLoggingLevel(
           this.initialLoggingLevel,
           this.getRequestOptions(),

core/mcp/types.ts

@@ -919,8 +919,16 @@ export interface InspectorClientOptions {
   pipeStderr?: boolean;
 
   /**
-   * Initial logging level to set after connection (if server supports logging)
+   * Initial logging level to set after connection, via `logging/setLevel`.
-   * If not provided, logging level will not be set automatically
+   * If not provided, the logging level will not be set automatically.
+   *
+   * **Legacy era only (#1990).** `logging/setLevel` is a legacy-era method, and
+   * the modern (2026-07-28) era rejects it — so this option is ignored on a
+   * modern connection even when the server advertises `logging`. Modern has no
+   * session-scoped level at all: the equivalent is the per-request
+   * `io.modelcontextprotocol/logLevel` `_meta` opt-in, configured through the
+   * `modernLogLevel` server setting and applied via
+   * `InspectorClient.setModernLogLevel()`.
    */
   initialLoggingLevel?: LoggingLevel;