CAMEL-26396: camel-jbang - AI tools: the MCP server never takes itself for an integration

docs/user-manual/modules/ROOT/pages/camel-jbang-mcp.adoc

@@ -812,7 +812,8 @@ help validate and scaffold that workflow, following the rules of the `rest-opena
 NOTE: Runtime tools require a running Camel application started via `camel run`. They communicate with the
 application through the file-based IPC protocol in `~/.camel/`. All tools accept an optional `nameOrPid`
 parameter; when omitted, the server auto-discovers the running Camel process (this works when exactly one
-process is running).
+process is running). The MCP server itself is never one of them: it is not listed, not selected when no name is
+given, and a call that names its pid is refused.
 
 ==== Process Discovery
 

dsl/camel-cli-connector/src/main/java/org/apache/camel/cli/connector/FileCliConnectorTransport.java

@@ -62,13 +62,16 @@ public class FileCliConnectorTransport extends ServiceSupport implements CliConn
     private CliSnapshotProducer snapshots;
     private Runnable shutdown;
     private ScheduledExecutorService executor;
+    private volatile Thread pollThread;
     private ScheduledFuture<?> scheduledFuture;
     private int delay = 1000;
     private long counter;
     private final Map<File, PendingAction> pending = new HashMap<>();
 
     // an action file this young that cannot be read may still be written: the Camel CLI before 4.24 writes it in place
     private static final long UNREADABLE_GRACE_MS = 2000;
+    // how long a stop waits for the poll in flight before it removes the files
+    private static final long STOP_POLL_TIMEOUT_MS = 5000;
 
     private record PendingAction(File output, boolean replyAlways, CompletableFuture<CliActionOutcome> outcome) {
     }
@@ -108,6 +111,7 @@ protected void doStart() throws Exception {
             String threadName = ThreadHelper.resolveThreadName(null, "LocalCliConnector");
             Thread thread = new Thread(r, threadName);
             thread.setDaemon(true);
+            pollThread = thread;
             return thread;
         });
 
@@ -436,6 +440,7 @@ protected void doStop() throws Exception {
         if (scheduledFuture != null) {
             scheduledFuture.cancel(false);
         }
+        awaitPoll();
         synchronized (this) {
             pending.forEach((request, action) -> {
                 action.outcome().cancel(true);
@@ -480,6 +485,29 @@ protected void doStop() throws Exception {
         }
     }
 
+    /**
+     * Waits a little for the poll in flight: a status written after the files are removed would stay behind, and the
+     * Camel CLI would list this process as a running integration after its Camel has stopped (CAMEL-26396). Not when
+     * the poll itself stops the transport, which would wait for itself.
+     */
+    private void awaitPoll() {
+        if (executor == null) {
+            return;
+        }
+        // the poll is cancelled, so the thread ends once the poll in flight is done
+        executor.shutdown();
+        if (Thread.currentThread() == pollThread) {
+            return;
+        }
+        try {
+            if (!executor.awaitTermination(STOP_POLL_TIMEOUT_MS, TimeUnit.MILLISECONDS)) {
+                LOG.debug("The poll of the Camel CLI connector has not finished within {} millis", STOP_POLL_TIMEOUT_MS);
+            }
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+        }
+    }
+
     private static String getPid() {
         return String.valueOf(ProcessHandle.current().pid());
     }

dsl/camel-cli-connector/src/test/java/org/apache/camel/cli/connector/FileCliConnectorTransportStopTest.java

@@ -0,0 +1,146 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.camel.cli.connector;
+
+import java.io.File;
+import java.nio.file.Path;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+import org.apache.camel.impl.DefaultCamelContext;
+import org.apache.camel.util.json.JsonObject;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+import org.junit.jupiter.api.parallel.Isolated;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.awaitility.Awaitility.await;
+
+/**
+ * CAMEL-26396: a stop waits for the status write in flight, so a stopped integration leaves no status file behind. The
+ * Camel CLI lists a live process with a status file as a running integration: the MCP server, whose scratch contexts
+ * ran with the connector, listed itself and took itself for the integration to evaluate in.
+ * <p>
+ * Isolated because it changes {@code user.home}, and every connector in this JVM writes files named after the same pid.
+ */
+@Isolated
+class FileCliConnectorTransportStopTest {
+
+    private static final String PID = String.valueOf(ProcessHandle.current().pid());
+
+    @TempDir
+    Path home;
+
+    private String oldHome;
+    private DefaultCamelContext context;
+
+    @BeforeEach
+    void useHome() {
+        oldHome = System.getProperty("user.home");
+        System.setProperty("user.home", home.toString());
+        context = new DefaultCamelContext();
+    }
+
+    @AfterEach
+    void restoreHome() {
+        context.stop();
+        System.setProperty("user.home", oldHome);
+    }
+
+    @Test
+    void aStatusWriteInFlightDoesNotOutliveTheStop() throws Exception {
+        SlowSnapshots snapshots = new SlowSnapshots();
+        FileCliConnectorTransport transport = new FileCliConnectorTransport();
+        transport.configure(context, (action, output) -> false, snapshots, () -> {
+        });
+        transport.start();
+        File status = home.resolve(".camel").resolve(PID + "-status.json").toFile();
+        // the first poll collects the status, which takes until the test lets it go on
+        assertThat(snapshots.collecting.await(10, TimeUnit.SECONDS)).isTrue();
+
+        Thread stopper = new Thread(transport::stop, "test-stop");
+        stopper.start();
+        // the stop is done, as it was at once before the fix, or it waits for the poll
+        await().atMost(10, TimeUnit.SECONDS).until(() -> switch (stopper.getState()) {
+            case TERMINATED, WAITING, TIMED_WAITING -> true;
+            default -> false;
+        });
+        snapshots.collected.countDown();
+
+        stopper.join(10_000);
+        assertThat(stopper.isAlive()).isFalse();
+        // the poll has written the status, before the stop removed the files or after
+        snapshots.poll.join(10_000);
+        assertThat(snapshots.poll.isAlive()).isFalse();
+        assertThat(status).doesNotExist();
+    }
+
+    /**
+     * Snapshots whose status takes until the test counts down {@link #collected}.
+     */
+    private static final class SlowSnapshots implements CliSnapshotProducer {
+
+        final CountDownLatch collecting = new CountDownLatch(1);
+        final CountDownLatch collected = new CountDownLatch(1);
+        volatile Thread poll;
+
+        @Override
+        public JsonObject status() throws Exception {
+            poll = Thread.currentThread();
+            collecting.countDown();
+            collected.await(10, TimeUnit.SECONDS);
+            JsonObject context = new JsonObject();
+            context.put("name", "demo");
+            context.put("phase", 4);
+            JsonObject root = new JsonObject();
+            root.put("context", context);
+            return root;
+        }
+
+        @Override
+        public JsonObject trace() {
+            return null;
+        }
+
+        @Override
+        public JsonObject debug() {
+            return null;
+        }
+
+        @Override
+        public JsonObject messageHistory() {
+            return null;
+        }
+
+        @Override
+        public JsonObject errors() {
+            return null;
+        }
+
+        @Override
+        public JsonObject receive() {
+            return null;
+        }
+
+        @Override
+        public JsonObject activity() {
+            return null;
+        }
+    }
+}

dsl/camel-jbang/camel-jbang-core/src/main/java/org/apache/camel/dsl/jbang/core/commands/ai/ExpressionEvaluator.java

@@ -24,6 +24,7 @@
 import org.apache.camel.Expression;
 import org.apache.camel.Predicate;
 import org.apache.camel.catalog.LanguageValidationResult;
+import org.apache.camel.dsl.jbang.core.common.ScratchContextHelper;
 import org.apache.camel.impl.DefaultCamelContext;
 import org.apache.camel.main.download.DependencyDownloaderClassLoader;
 import org.apache.camel.main.download.MavenDependencyDownloader;
@@ -193,7 +194,8 @@ private static void evaluateLocally(
      */
     private static boolean evaluateWith(
             ClassLoader loader, String lang, String expression, String body, boolean predicate, JsonObject result) {
-        try (DefaultCamelContext context = new DefaultCamelContext(false)) {
+        // without the CLI connector, which would make this process, such as the MCP server, a running integration
+        try (DefaultCamelContext context = ScratchContextHelper.withoutCliConnector(new DefaultCamelContext(false))) {
             if (loader != null) {
                 // before the start: the language resolver reads the class loader as the context comes up
                 context.setApplicationContextClassLoader(loader);

dsl/camel-jbang/camel-jbang-core/src/main/java/org/apache/camel/dsl/jbang/core/commands/ai/IntegrationLauncher.java

@@ -570,6 +570,10 @@ private static String readTail(Path output) {
     public static String control(ToolContext ctx, String action) {
         ctx.requireProcess();
         long pid = ctx.pid();
+        if (pid == ProcessHandle.current().pid()) {
+            // the tools run in this process: it cannot kill itself (the JDK refuses), nor answer an action it waits for
+            throw ToolContext.thisProcess(pid);
+        }
         return switch (action) {
             case "stop" -> ctx.stopApplication();
             case "kill" -> {

dsl/camel-jbang/camel-jbang-core/src/main/java/org/apache/camel/dsl/jbang/core/commands/ai/ToolContext.java

@@ -222,12 +222,13 @@ private CamelCatalog loadCatalog() {
      * Selects the process a tool call names ({@code name} is an integration name or pid), or keeps the current
      * selection when the call names none.
      *
-     * @throws ToolExecutionException when the name matches no running process
+     * @throws ToolExecutionException when the name matches no running process, or is the pid of this process
      */
     public void selectProcess(String nameOrPid) {
         if (nameOrPid == null || nameOrPid.isBlank()) {
             return;
         }
+        refuseThisProcess(nameOrPid);
         RuntimeHelper.ProcessInfo p = RuntimeHelper.findProcess(nameOrPid);
         if (p == null) {
             throw new ToolExecutionException(
@@ -237,6 +238,27 @@ public void selectProcess(String nameOrPid) {
         selectProcess(p.pid());
     }
 
+    /**
+     * Refuses the pid of this process, which runs the tools: a status file of its own comes from a CamelContext it ran
+     * for itself, never from an integration, and it would wait for itself to answer an action (CAMEL-26396).
+     *
+     * @throws ToolExecutionException when the name or pid is the pid of this process
+     */
+    static void refuseThisProcess(String nameOrPid) {
+        if (RuntimeHelper.isThisProcess(nameOrPid)) {
+            throw thisProcess(ProcessHandle.current().pid());
+        }
+    }
+
+    /**
+     * The error for a tool call on the pid of this process (see {@link #refuseThisProcess(String)}).
+     */
+    static ToolExecutionException thisProcess(long pid) {
+        return new ToolExecutionException(
+                "pid " + pid + " is the process that runs these tools (the MCP server, camel ask or the TUI), not a"
+                                          + " Camel integration; list_processes shows the integrations");
+    }
+
     public String readStatus(String section) {
         requireProcess();
         return RuntimeHelper.readStatusSection(pid, section);

dsl/camel-jbang/camel-jbang-core/src/main/java/org/apache/camel/dsl/jbang/core/commands/ai/ToolRegistry.java

@@ -134,6 +134,7 @@ private static void registerProcessTools() {
                     if (name == null || name.isBlank()) {
                         throw new ToolExecutionException("name or PID is required");
                     }
+                    ToolContext.refuseThisProcess(name);
                     RuntimeHelper.ProcessInfo found = ctx.findProcess(name);
                     if (found == null) {
                         List<RuntimeHelper.ProcessInfo> processes = ctx.discoverProcesses();

dsl/camel-jbang/camel-jbang-core/src/main/java/org/apache/camel/dsl/jbang/core/commands/version/VersionList.java

@@ -60,10 +60,12 @@
 import org.apache.camel.dsl.jbang.core.common.RuntimeCompletionCandidates;
 import org.apache.camel.dsl.jbang.core.common.RuntimeType;
 import org.apache.camel.dsl.jbang.core.common.RuntimeTypeConverter;
+import org.apache.camel.dsl.jbang.core.common.ScratchContextHelper;
 import org.apache.camel.dsl.jbang.core.common.VersionHelper;
 import org.apache.camel.dsl.jbang.core.model.VersionListDTO;
 import org.apache.camel.main.KameletMain;
 import org.apache.camel.main.download.MavenDependencyDownloader;
+import org.apache.camel.spi.CliConnectorFactory;
 import org.apache.camel.tooling.maven.RepositoryResolver;
 import org.apache.camel.tooling.model.ReleaseModel;
 import org.apache.camel.util.StringHelper;
@@ -400,6 +402,9 @@ Stream<CamelAndRuntimeVersions> downloadReleases() {
                     mavenResolver.fresh());
         }
         KameletMain main = new KameletMain(CAMEL_INSTANCE_TYPE);
+        // only to download: without the CLI connector, which would list this process (such as the MCP server, whose
+        // camel_version_list runs this) as a running integration
+        main.bind(CliConnectorFactory.FACTORY, ScratchContextHelper.disabledCliConnectorFactory());
         try {
             main.setFresh(mavenResolver.fresh());
             main.setDownload(mavenResolver.download());

dsl/camel-jbang/camel-jbang-core/src/main/java/org/apache/camel/dsl/jbang/core/common/RuntimeHelper.java

@@ -61,10 +61,13 @@ private RuntimeHelper() {
     /**
      * Discovers all running Camel processes by scanning {@code ~/.camel/} for {@code {pid}-status.json} files and
      * verifying each PID is still alive.
+     * <p>
+     * This process is never one of them: it runs the tools (camel ask, the TUI, the MCP server), and a status file of
+     * its own comes from a CamelContext it ran for itself, not from an integration (CAMEL-26396).
      */
     public static List<ProcessInfo> discoverProcesses() {
         List<ProcessInfo> result = new ArrayList<>();
-        for (ProcessFinder.CamelProcess p : ProcessFinder.findAll()) {
+        for (ProcessFinder.CamelProcess p : others(ProcessFinder.findAll())) {
             result.add(new ProcessInfo(p.pid(), p.name(), p.contextName()));
         }
         return result;
@@ -73,20 +76,37 @@ public static List<ProcessInfo> discoverProcesses() {
     /**
      * Finds a single Camel process matching the given name or PID. Returns {@code null} if no match is found or if
      * multiple processes match. When {@code nameOrPid} is {@code null} and exactly one process is running, returns that
-     * process.
+     * process. This process never matches, also not by its pid (see {@link #discoverProcesses()}).
      *
      * @param nameOrPid a process name (with optional wildcard), a numeric PID string, or {@code null} for auto-detect
      */
     public static ProcessInfo findProcess(String nameOrPid) {
-        List<ProcessFinder.CamelProcess> found = nameOrPid != null && !nameOrPid.isBlank()
-                ? ProcessFinder.find(nameOrPid) : ProcessFinder.findAll();
+        List<ProcessFinder.CamelProcess> found = others(nameOrPid != null && !nameOrPid.isBlank()
+                ? ProcessFinder.find(nameOrPid) : ProcessFinder.findAll());
         if (found.size() == 1) {
             ProcessFinder.CamelProcess p = found.get(0);
             return new ProcessInfo(p.pid(), p.name(), p.contextName());
         }
         return null;
     }
 
+    /**
+     * Whether the name or pid is the pid of this process, which {@link #findProcess(String)} never finds.
+     *
+     * @since 4.24
+     */
+    public static boolean isThisProcess(String nameOrPid) {
+        if (nameOrPid == null || !nameOrPid.matches("\\d{1,18}")) {
+            return false;
+        }
+        return Long.parseLong(nameOrPid) == ProcessHandle.current().pid();
+    }
+
+    private static List<ProcessFinder.CamelProcess> others(List<ProcessFinder.CamelProcess> processes) {
+        long self = ProcessHandle.current().pid();
+        return processes.stream().filter(p -> p.pid() != self).toList();
+    }
+
     /**
      * Reads the full status JSON for the given process.
      *