Remove port-finding logic for MCP server's HTTP transport

internal/cmd/mcp_start_http.go

@@ -7,6 +7,7 @@ import (
 	"log/slog"
 	"net"
 	"net/http"
+	"strconv"
 
 	"github.com/spf13/cobra"
 
@@ -24,7 +25,7 @@ func buildMCPHTTPCmd(app *common.App) *cobra.Command {
 		Short: "Start MCP server with HTTP transport",
 		Long: `Start the MCP server using HTTP transport.
 
-The server will automatically find an available port if the specified port is busy.`,
+The server listens on the given port and fails if that port is already in use.`,
 		Example: `  # Start HTTP server on default port 8080
   tiger mcp start http
 
@@ -64,27 +65,14 @@ func startHTTPServer(cmd *cobra.Command, app *common.App, host string, port int)
 	}
 	defer server.Close()
 
-	// Find available port and get the listener
-	listener, actualPort, err := getListener(host, port)
+	address := net.JoinHostPort(host, strconv.Itoa(port))
+	listener, err := net.Listen("tcp", address)
 	if err != nil {
-		logger.Error("Failed to get listener",
-			slog.String("host", host),
-			slog.Int("port", port),
-			slog.Any("error", err),
-		)
-		return fmt.Errorf("failed to get listener: %w", err)
+		logger.Error("Failed to listen", slog.Any("error", err))
+		return fmt.Errorf("failed to listen: %w", err)
 	}
 	defer listener.Close()
 
-	if actualPort != port {
-		logger.Info("Specified port was busy, using alternative port",
-			slog.Int("requested_port", port),
-			slog.Int("actual_port", actualPort),
-		)
-	}
-
-	address := fmt.Sprintf("%s:%d", host, actualPort)
-
 	// Create HTTP server
 	httpServer := &http.Server{
 		Handler: server.HTTPHandler(),
@@ -128,15 +116,3 @@ func startHTTPServer(cmd *cobra.Command, app *common.App, host string, port int)
 	}
 	return nil
 }
-
-// getListener finds an available port starting from the specified port and returns the listener
-func getListener(host string, startPort int) (net.Listener, int, error) {
-	for port := startPort; port < startPort+100; port++ {
-		address := fmt.Sprintf("%s:%d", host, port)
-		listener, err := net.Listen("tcp", address)
-		if err == nil {
-			return listener, port, nil
-		}
-	}
-	return nil, 0, fmt.Errorf("no available port found in range %d-%d", startPort, startPort+99)
-}

internal/cmd/mcp_start_http_test.go

@@ -12,7 +12,7 @@ import (
 )
 
 // freePort returns a port nothing is listening on, and (when hold is true)
-// keeps it occupied for the rest of the test so the command has to fall back.
+// keeps it occupied for the rest of the test so binding it fails.
 func freePort(t *testing.T, hold bool) int {
 	t.Helper()
 	listener, err := net.Listen("tcp", "localhost:0")
@@ -56,27 +56,13 @@ INFO Tiger MCP server started address=localhost:%d
 `, port) + shutdown),
 		},
 		{
-			// The port scan walks forward from the requested one. Which port
-			// it lands on depends on what else is running, so only the
-			// fallback itself is asserted.
-			name: "falls back to another port when the requested one is busy",
-			args: []string{"mcp", "start", "http", "--port", fmt.Sprint(busyPort)},
-			opts: append(noDocsProxy(nil), withContext(cancelled)),
-			wantStderr: matchLogPort(fmt.Sprintf(`INFO Docs MCP proxy is disabled
-INFO Specified port was busy, using alternative port requested_port=%d actual_port=<port>
-INFO Tiger MCP server started address=localhost:<port>
-`, busyPort) + shutdown),
-		},
-		{
-			// 192.0.2.1 is TEST-NET-1: it resolves to nothing local, so
-			// every port in the scan range fails to bind.
-			name:    "reports when no port in range is available",
-			args:    []string{"mcp", "start", "http", "--host", "192.0.2.1"},
+			name:    "fails when the requested port is busy",
+			args:    []string{"mcp", "start", "http", "--port", fmt.Sprint(busyPort)},
 			opts:    append(noDocsProxy(nil), withContext(cancelled)),
-			wantErr: "failed to get listener: no available port found in range 8080-8179",
-			wantStderr: matchLog(`INFO Docs MCP proxy is disabled
-ERROR Failed to get listener host=192.0.2.1 port=8080 error="no available port found in range 8080-8179"
-`),
+			wantErr: fmt.Sprintf("failed to listen: listen tcp 127.0.0.1:%d: bind: address already in use", busyPort),
+			wantStderr: matchLog(fmt.Sprintf(`INFO Docs MCP proxy is disabled
+ERROR Failed to listen error="listen tcp 127.0.0.1:%d: bind: address already in use"
+`, busyPort)),
 		},
 		{
 			name:    "rejects positional args",

internal/cmd/mcp_test.go

@@ -3,7 +3,6 @@ package cmd
 import (
 	"maps"
 	"regexp"
-	"strings"
 	"testing"
 )
 
@@ -31,16 +30,3 @@ func matchLog(want string) matcher {
 		assertOutput(t, logTimestamp.ReplaceAllString(got, ""), want)
 	})
 }
-
-// matchLogPort is matchLog for output naming a port the OS picked rather than
-// one the test chose. The want text is matched literally except for "<port>",
-// which stands in for any port number.
-func matchLogPort(want string) matcher {
-	re := regexp.MustCompile("^" + strings.ReplaceAll(regexp.QuoteMeta(want), "<port>", `\d+`) + "$")
-	return matchFunc(func(t *testing.T, got string) {
-		t.Helper()
-		if stripped := logTimestamp.ReplaceAllString(got, ""); !re.MatchString(stripped) {
-			t.Errorf("log = %q, want %q (<port> matching any port)", stripped, want)
-		}
-	})
-}