test: drop strictPort and document the port collision instead

strictPort was a new test-server config option — plus its validation and 18
tests — invented solely to keep one fixture's hard-coded issuer port honest.
That is infrastructure built for a screenshot, so it goes.

test-servers/src is now byte-identical to v2/main again. The fixture keeps its
fixed port and docs/test-servers.md carries the caveat instead, written to be
actionable rather than merely cautionary: the failure mode is confusing rather
than obvious, since a relocated server leaves discovery pointing at whatever
unrelated process holds 8091, so the note says to check the port before
believing what the flow does.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018MvNbmAtQuWhDvzi4yXDju
Signed-off-by: cliffhall <cliff@futurescale.com>

test-servers/configs/oauth-insecure-token-endpoint-http.json

@@ -21,7 +21,6 @@
   },
   "transport": {
     "type": "streamable-http",
-    "port": 8091,
-    "strictPort": true
+    "port": 8091
   }
 }

test-servers/src/composable-test-server.ts

@@ -456,17 +456,6 @@ export interface ServerConfig {
     | undefined; // Optional callback to customize resource handler during registration
   serverType?: "sse" | "streamable-http"; // Transport type (default: "streamable-http")
   port?: number; // Port to use (optional, will find available port if not specified)
-  /**
-   * Refuse to relocate: bind {@link port} exactly, or fail with EADDRINUSE.
-   *
-   * Off by default, because walking to the next free port is what lets several
-   * fixtures run side by side. It exists for a fixture whose *advertised*
-   * configuration hard-codes the port — `oauth-insecure-token-endpoint-http.json`
-   * puts it in an OAuth issuer — where relocating leaves the server announcing
-   * one port while its metadata still points at another process entirely, and
-   * the fixture silently stops reproducing what it exists to reproduce.
-   */
-  strictPort?: boolean;
   /**
    * Whether to advertise listChanged capability for each list type
    * If enabled, modification tools will send list_changed notifications

test-servers/src/load-config.ts

@@ -119,8 +119,6 @@ export interface ConfigFile {
   transport: {
     type: "stdio" | "streamable-http" | "sse";
     port?: number;
-    /** Bind `port` exactly, or fail — see `ServerConfig.strictPort`. */
-    strictPort?: boolean;
     /**
      * Serve the modern (2026-07-28) protocol era via the SDK's
      * `createMcpHandler` (only valid with `type: "streamable-http"`). `true`
@@ -198,48 +196,6 @@ function validateConfig(
       `Invalid config in ${filePath}: transport.type must be stdio, streamable-http, or sse`,
     );
   }
-  // `strictPort` is consumed as a plain truthiness check at bind time, so a
-  // string `"false"` would read as *enabled* and silently disable the port walk
-  // — the opposite of what the author wrote. Validate the type here, where the
-  // file is being trusted, rather than letting it through as a `ConfigFile`.
-  if (
-    transport.strictPort !== undefined &&
-    typeof transport.strictPort !== "boolean"
-  ) {
-    throw new Error(
-      `Invalid config in ${filePath}: transport.strictPort must be a boolean`,
-    );
-  }
-
-  // Beyond the type: reject every combination that cannot honor the flag's
-  // contract, because each of them fails *silently* — the fixture looks strict
-  // and relocates anyway, which is the failure the flag exists to prevent.
-  //
-  //  - a string port (`"0"`, `"8091"`) is truthy, so it slips past the runtime
-  //    "no port to be strict about" guard, and Node then coerces `"0"` to the
-  //    dynamic port 0;
-  //  - a non-integer or out-of-range port cannot be bound as written;
-  //  - on `stdio` there is no listener at all, and `resolveConfig` drops the
-  //    flag, so it silently does nothing.
-  if (transport.strictPort === true) {
-    if (transportType === "stdio") {
-      throw new Error(
-        `Invalid config in ${filePath}: transport.strictPort requires an HTTP transport (streamable-http or sse)`,
-      );
-    }
-    const port = transport.port;
-    if (
-      typeof port !== "number" ||
-      !Number.isInteger(port) ||
-      port < 1 ||
-      port > 65535
-    ) {
-      throw new Error(
-        `Invalid config in ${filePath}: transport.strictPort requires transport.port to be an integer in 1-65535 (got ${JSON.stringify(port)})`,
-      );
-    }
-  }
-
   // Only reject *enabling* modern on a non-HTTP transport; a falsy `modern`
   // (e.g. `false`) is a no-op that `resolveConfig` normalizes away.
   if (transport.modern && transportType !== "streamable-http") {

test-servers/src/resolve-config.ts

@@ -102,7 +102,6 @@ export function resolveConfig(config: ConfigFile): ServerConfig {
       ? (transport.type as "sse" | "streamable-http")
       : undefined,
     port: isHttp ? transport.port : undefined,
-    strictPort: isHttp ? transport.strictPort : undefined,
   };
 
   // Normalize the modern flag: `true` is shorthand for the default (dual-era

test-servers/src/test-server-http.ts

@@ -400,39 +400,9 @@ export class TestServerHttp {
     const serverType = this.config.serverType ?? "streamable-http";
     const requestedPort = this.config.port;
 
-    // `strictPort` means "bind exactly this port, or fail". With no fixed port
-    // to bind there is nothing to be strict about, and falling through to an
-    // OS-assigned one would let a misconfigured fixture look strict while
-    // relocating on every run — the exact failure the flag exists to prevent,
-    // now silent. Reject the combination instead.
-    if (
-      this.config.strictPort &&
-      (typeof requestedPort !== "number" ||
-        !Number.isInteger(requestedPort) ||
-        requestedPort < 1 ||
-        requestedPort > 65535)
-    ) {
-      // `loadConfig` rejects these for a config file; this covers a
-      // programmatic caller, and specifically a value that is *truthy* but not
-      // bindable as written — a string `"0"` slips past a bare falsiness check
-      // and Node then coerces it to the dynamic port 0, so the fixture looks
-      // strict and relocates anyway.
-      throw new Error(
-        `strictPort requires an explicit port as an integer in 1-65535 (got ${JSON.stringify(requestedPort)}): ` +
-          "there is nothing to bind strictly otherwise.",
-      );
-    }
-
     // If a port is explicitly requested, find an available port starting from that value
-    // Otherwise, use 0 to let the OS assign an available port.
-    // `strictPort` opts out of the walk: bind the requested port or fail loudly
-    // (see the field's doc comment — a relocated server whose advertised config
-    // hard-codes the port is worse than one that does not start).
-    const port = requestedPort
-      ? this.config.strictPort
-        ? requestedPort
-        : await findAvailablePort(requestedPort)
-      : 0;
+    // Otherwise, use 0 to let the OS assign an available port
+    const port = requestedPort ? await findAvailablePort(requestedPort) : 0;
 
     if (serverType === "streamable-http") {
       return this.startHttp(port);