feat(debugger): integrate NX Tcl Remote Debugger into NX Postprocessor

Embed the NX Tcl Remote Debugger into the NX Postprocessor extension.
Add a new debugging client, protocol, and adapter logic to
drive attach/launch, breakpoints, stepping, and evaluation
via the runtime adapter.

- Introduced a client debugger with a new adapter and protocol
- Wired attach/launch, breakpoints, stepping, and evaluation
- Updated docs and licensing to reflect the embedded debugger

.vscodeignore

@@ -9,6 +9,7 @@ vite.config.js
 .prettierrc.json
 esbuild.js
 .gitea
+**/.ruff_cache/**
 .venv/**
 .nox/**
 server/.venv/**
@@ -18,4 +19,7 @@ server/.nox/**
 **/requirements.in
 **/server/src/_debug_server.py
 server/noxfile.py
-client/**
+server/.claude/**
+server/tests/**
+client/**
+dist/**/*.map

CHANGELOG.md

@@ -1,5 +1,11 @@
 ## Unreleased
 
+- Integrate the NX Tcl Remote Debugger directly into NX Postprocessor Support
+- Add `nx-tcl` attach configurations and breakpoint support for TCL and DEF files
+- Support breakpoints, stepping, stack frames, variables, watches, evaluation, logpoints, hit conditions, and Tcl error stops
+- Add generation-safe stack and variable references so delayed VS Code requests cannot address stale NX frames
+- Add command-buffer breakpoint handling for `LIB_GE_command_buffer_edit_*` source bodies
+- Extend the README with launch configuration, path mapping, and debugger usage
 - Prevent truncated TCL inlay hints and add configurable parameter hint modes
 - Add inlay hints for built-in NX procedures, variadic arguments, and visible ranges
 - Add inlay hint documentation and navigation to custom procedure definitions

README.md

@@ -1,6 +1,6 @@
 # NX Postprocessor Support
 
-A comprehensive VS Code extension providing language support for NX CAM postprocessor development, including CDL, TCL, and DEF files.
+A comprehensive VS Code extension providing language support and remote debugging for NX CAM postprocessor development, including CDL, TCL, and DEF files.
 
 ## Features
 
@@ -10,6 +10,7 @@ A comprehensive VS Code extension providing language support for NX CAM postproc
 - **Intelligent Code Analysis** - Linting and error detection for postprocessor code
 - **Auto-completion** - Context-aware code completion for faster development
 - **Signature Help** - Shows parameters and documentation for custom and NX procedures
+- **NX Tcl Remote Debugger** - Breakpoints, stepping, call stack, scopes, variables, watches, evaluation, logpoints, hit conditions, and Tcl error stops directly in a running NX Post process
 
 ## Supported File Types
 
@@ -24,6 +25,10 @@ A comprehensive VS Code extension providing language support for NX CAM postproc
 3. Open any `.cdl`, `.tcl`, or `.def` file
 4. The extension will automatically activate and provide language support
 
+The former standalone `NX Tcl Remote Debugger` extension is no longer required. Disable or
+uninstall `local-nx.nx-tcl-debug` before using the integrated debugger because both extensions
+register the same `nx-tcl` debug type.
+
 ## Configuration
 
 The extension can be configured through VS Code settings:
@@ -38,6 +43,49 @@ TCL files default to unlimited inlay hint length so that VS Code does not
 truncate later parameter names on a line. An explicit user setting for
 `editor.inlayHints.maximumLength` still takes precedence.
 
+## NX Tcl Remote Debugger
+
+### Add a VS Code attach configuration
+
+Create `.vscode/launch.json` through **Run and Debug: create a launch.json file** and select
+**NX Tcl: Attach to NX Post**, or use this configuration:
+
+```json
+{
+  "version": "0.2.0",
+  "configurations": [
+    {
+      "type": "nx-tcl",
+      "request": "attach",
+      "name": "Attach to NX Post Tcl",
+      "host": "127.0.0.1",
+      "port": 4711,
+      "connectTimeout": 120000,
+      "stopOnEntry": false,
+      "breakOnError": true,
+      "localRoot": "${workspaceFolder}"
+    }
+  ]
+}
+```
+
+When VS Code and NX see the source through different roots, set `remoteRoot` to the root used by
+NX and keep `localRoot` as the corresponding workspace root.
+
+### Start debugging
+
+1. Set breakpoints on executable Tcl or DEF commands.
+2. Start **Attach to NX Post Tcl** in VS Code before running the postprocessor.
+3. Start postprocessing in NX.
+4. Use Continue, Step Over, Step Into, Step Out, Pause, Variables, Watch, and the Debug Console as
+   with a normal source debugger.
+
+Breakpoints remain active and stop at every real invocation. Use a hit condition such as `1` for
+a one-time stop. Blank lines, comments, declarations, and multiline Tcl commands may be relocated
+to the nearest executable command; VS Code shows the resolved line. Dynamic
+`LIB_GE_command_buffer_edit_*` bodies are mapped back to their original source and owning Tcl
+procedure.
+
 ## Usage
 
 Simply open any supported file type and enjoy:
@@ -48,6 +96,7 @@ Simply open any supported file type and enjoy:
 - Code formatting (Format Document command)
 - Hover information
 - Signature help while entering procedure arguments
+- Remote NX Tcl debugging with breakpoints and full stepping
 
 ## Development and debugging
 
@@ -56,6 +105,7 @@ Install the root and client dependencies before the first debug session:
 ```powershell
 npm install
 npm install --prefix client
+npm run test:debugger
 ```
 
 Use one of the checked-in VS Code launch configurations:
@@ -78,4 +128,5 @@ This extension is actively maintained. For issues or feature requests, please vi
 
 ## License
 
-AGPL-3.0 License - see LICENSE file for details.
+AGPL-3.0 License - see LICENSE file for details. The embedded NX Tcl Remote Debugger adapter
+retains its MIT notice in `debugger/NX_TCL_DEBUGGER_LICENSE.txt`.

client/src/debugger/debugAdapter.js

@@ -0,0 +1,650 @@
+'use strict';
+
+const path = require('path');
+const { RuntimeConnection, encodeHex, decodeHex } = require('./protocol');
+
+const THREAD_ID = 1;
+
+class NxDebugAdapter {
+  constructor(input = process.stdin, output = process.stdout) {
+    this.input = input;
+    this.output = output;
+    this.inputBuffer = Buffer.alloc(0);
+    this.sequence = 1;
+    this.runtime = null;
+    this.terminated = false;
+    this.explicitDisconnect = false;
+    this.localRoot = '';
+    this.remoteRoot = '';
+    this.nextBreakpointId = 1;
+    // VS Code can expose the same physical file through more than one source
+    // identity (for example, drive mappings or differently cased workspace
+    // roots). SETBPS replaces all breakpoints for a runtime path, so retain
+    // each DAP source group and send their union to NX.
+    this.sourceBreakpointGroups = new Map();
+    this.pendingStartRequest = null;
+    this.resumeInProgress = 0;
+    this.pendingStoppedEvents = [];
+    this.isPaused = false;
+    // DAP frame/variable IDs can outlive a stop in the VS Code UI. Runtime
+    // levels and references, however, are valid only for the current Tcl
+    // pause. Give every stop adapter-owned IDs so a late request can never
+    // accidentally address a same-numbered frame from a later pause.
+    this.nextFrameId = 1;
+    this.frameReferences = new Map();
+    this.runtimeToFrameReference = new Map();
+    this.nextVariablesReference = 1;
+    this.variableReferences = new Map();
+    this.runtimeToVariableReference = new Map();
+
+    input.on('data', (chunk) => this.onData(chunk));
+    input.on('end', () => this.dispose());
+    input.resume();
+  }
+
+  onData(chunk) {
+    this.inputBuffer = Buffer.concat([this.inputBuffer, chunk]);
+    while (true) {
+      const headerEnd = this.inputBuffer.indexOf('\r\n\r\n');
+      if (headerEnd < 0) return;
+      const header = this.inputBuffer.subarray(0, headerEnd).toString('ascii');
+      const match = /Content-Length:\s*(\d+)/i.exec(header);
+      if (!match) throw new Error('missing DAP Content-Length header');
+      const contentLength = Number(match[1]);
+      const messageEnd = headerEnd + 4 + contentLength;
+      if (this.inputBuffer.length < messageEnd) return;
+      const payload = this.inputBuffer.subarray(headerEnd + 4, messageEnd).toString('utf8');
+      this.inputBuffer = this.inputBuffer.subarray(messageEnd);
+      const message = JSON.parse(payload);
+      if (message.type === 'request') {
+        this.handleRequest(message).catch((error) => this.sendErrorResponse(message, error));
+      }
+    }
+  }
+
+  send(message) {
+    message.seq = this.sequence++;
+    const json = JSON.stringify(message);
+    this.output.write(`Content-Length: ${Buffer.byteLength(json, 'utf8')}\r\n\r\n${json}`);
+  }
+
+  sendResponse(request, body = {}) {
+    this.send({
+      type: 'response',
+      request_seq: request.seq,
+      success: true,
+      command: request.command,
+      body,
+    });
+  }
+
+  sendErrorResponse(request, error) {
+    this.send({
+      type: 'response',
+      request_seq: request.seq,
+      success: false,
+      command: request.command,
+      message: error instanceof Error ? error.message : String(error),
+    });
+  }
+
+  sendEvent(event, body = {}) {
+    this.send({ type: 'event', event, body });
+  }
+
+  async handleRequest(request) {
+    const args = request.arguments || {};
+    switch (request.command) {
+      case 'initialize':
+        this.sendResponse(request, {
+          supportsConfigurationDoneRequest: true,
+          supportsConditionalBreakpoints: true,
+          supportsHitConditionalBreakpoints: true,
+          supportsLogPoints: true,
+          supportsEvaluateForHovers: true,
+          supportsSetVariable: true,
+          supportsExceptionFilterOptions: true,
+          exceptionBreakpointFilters: [
+            { filter: 'tclError', label: 'Tcl errors', description: 'Break when a Tcl command returns TCL_ERROR' },
+          ],
+          supportsTerminateRequest: true,
+        });
+        break;
+
+      case 'attach':
+      case 'launch':
+        await this.attach(args);
+        this.pendingStartRequest = request;
+        this.sendEvent('initialized');
+        break;
+
+      case 'configurationDone':
+        await this.runtime.request('CONFIGDONE');
+        this.sendResponse(request);
+        if (this.pendingStartRequest) {
+          this.sendResponse(this.pendingStartRequest);
+          this.pendingStartRequest = null;
+        }
+        break;
+
+      case 'setBreakpoints':
+        await this.setBreakpoints(request, args);
+        break;
+
+      case 'setExceptionBreakpoints': {
+        const filters = args.filters || [];
+        await this.runtime.request('SETEXCEPTIONS', filters);
+        this.sendResponse(request, {
+          breakpoints: filters.map(() => ({ verified: true })),
+        });
+        break;
+      }
+
+      case 'threads':
+        this.sendResponse(request, { threads: [{ id: THREAD_ID, name: 'NX Post Tcl' }] });
+        break;
+
+      case 'stackTrace':
+        await this.stackTrace(request);
+        break;
+
+      case 'scopes':
+        await this.scopes(request, args);
+        break;
+
+      case 'variables':
+        await this.variables(request, args);
+        break;
+
+      case 'evaluate':
+        await this.evaluate(request, args);
+        break;
+
+      case 'setVariable':
+        await this.setVariable(request, args);
+        break;
+
+      case 'continue':
+        await this.resume(request, 'CONTINUE', { allThreadsContinued: true });
+        break;
+
+      case 'next':
+        await this.resume(request, 'NEXT');
+        break;
+
+      case 'stepIn':
+        await this.resume(request, 'STEPIN');
+        break;
+
+      case 'stepOut':
+        await this.resume(request, 'STEPOUT');
+        break;
+
+      case 'pause':
+        await this.runtime.request('PAUSE');
+        this.sendResponse(request);
+        break;
+
+      case 'disconnect':
+      case 'terminate':
+        await this.disconnect(request);
+        break;
+
+      default:
+        this.sendResponse(request);
+        break;
+    }
+  }
+
+  async attach(args) {
+    const host = args.host || '127.0.0.1';
+    const port = Number(args.port || 4711);
+    const timeout = Number(args.connectTimeout || 120000);
+    this.localRoot = args.localRoot ? path.resolve(args.localRoot) : '';
+    this.remoteRoot = args.remoteRoot ? this.normalizePath(args.remoteRoot) : '';
+    this.sourceBreakpointGroups.clear();
+    this.isPaused = false;
+    this.resetStoppedReferences(true);
+
+    this.runtime = new RuntimeConnection();
+    this.runtime.on('event', (name, fields) => this.onRuntimeEvent(name, fields));
+    this.runtime.on('runtimeError', (error) => {
+      this.sendEvent('output', { category: 'stderr', output: `NX: ${error.message}\n` });
+    });
+    this.runtime.on('close', () => {
+      if (!this.explicitDisconnect) this.sendTerminated();
+    });
+
+    const started = Date.now();
+    let lastError;
+    while (Date.now() - started < timeout) {
+      try {
+        await this.runtime.connect(host, port);
+        lastError = null;
+        break;
+      } catch (error) {
+        lastError = error;
+        await new Promise((resolve) => setTimeout(resolve, 250));
+      }
+    }
+    if (lastError) {
+      throw new Error(`could not connect to NX at ${host}:${port}: ${lastError.message}`);
+    }
+    await this.runtime.request('CONFIG', [args.stopOnEntry ? 1 : 0, args.breakOnError ? 1 : 0]);
+  }
+
+  async setBreakpoints(request, args) {
+    const sourcePath = args.source && args.source.path ? args.source.path : '';
+    const remotePath = this.toRemotePath(sourcePath);
+    const sourceKey = this.breakpointSourceKey(args.source, sourcePath);
+    const remoteKey = this.breakpointRemoteKey(remotePath);
+    const requested = args.breakpoints || (args.lines || []).map((line) => ({ line }));
+    const records = requested.map((breakpoint) => ({
+      id: this.nextBreakpointId++,
+      line: breakpoint.line,
+      condition: breakpoint.condition || '',
+      hitCondition: breakpoint.hitCondition || '',
+      logMessage: breakpoint.logMessage || '',
+    }));
+    if (!this.isTclSource(sourcePath)) {
+      this.sourceBreakpointGroups.delete(sourceKey);
+      // VS Code forwards breakpoints from every language to every active debug
+      // session. Clear any stale runtime entry left by an older adapter, but do
+      // not make the NX Tcl runtime parse or instrument a Python source file.
+      await this.runtime.request('SETBPS', [encodeHex(remotePath), 0]);
+      this.sendResponse(request, {
+        breakpoints: records.map((breakpoint) => ({
+          id: breakpoint.id,
+          verified: false,
+          line: breakpoint.line,
+          source: args.source,
+          message: 'NX Tcl Remote Debugger supports breakpoints only in .tcl and .def files',
+        })),
+      });
+      return;
+    }
+
+    this.sourceBreakpointGroups.set(sourceKey, { remotePath, remoteKey, records });
+
+    // Collapse exact duplicates shared by aliases, while remembering which
+    // runtime breakpoint represents every DAP breakpoint ID. This keeps hit
+    // counts and log points from firing twice for one Tcl command.
+    const mergedBreakpoints = [];
+    const mergedBySignature = new Map();
+    const representativeById = new Map();
+    for (const group of this.sourceBreakpointGroups.values()) {
+      if (group.remoteKey !== remoteKey) continue;
+      for (const breakpoint of group.records) {
+        const signature = this.breakpointSignature(breakpoint);
+        let representative = mergedBySignature.get(signature);
+        if (!representative) {
+          representative = breakpoint;
+          mergedBySignature.set(signature, representative);
+          mergedBreakpoints.push(representative);
+        }
+        representativeById.set(breakpoint.id, representative.id);
+      }
+    }
+
+    const fields = [encodeHex(remotePath), mergedBreakpoints.length];
+    for (const breakpoint of mergedBreakpoints) {
+      fields.push(
+        breakpoint.id,
+        breakpoint.line,
+        encodeHex(breakpoint.condition),
+        encodeHex(breakpoint.hitCondition),
+        encodeHex(breakpoint.logMessage),
+      );
+    }
+    const runtimeResponse = await this.runtime.request('SETBPS', fields);
+    const responseFields = runtimeResponse.fields || [];
+    const responseCount = Number(responseFields[0] || 0);
+    const responseStride = responseFields.length >= 1 + responseCount * 4 ? 4 : 2;
+    const runtimeBreakpoints = new Map();
+    let responseCursor = 1;
+    for (let index = 0; index < responseCount; index++) {
+      const id = Number(responseFields[responseCursor++]);
+      const line = Number(responseFields[responseCursor++]);
+      let verified = true;
+      let message = '';
+      if (responseStride === 4) {
+        verified = responseFields[responseCursor++] === '1';
+        message = decodeHex(responseFields[responseCursor++]);
+      }
+      runtimeBreakpoints.set(id, { line, verified, message });
+    }
+    this.sendResponse(request, {
+      breakpoints: records.map((breakpoint) => {
+        const representativeId = representativeById.get(breakpoint.id);
+        const runtimeBreakpoint = runtimeBreakpoints.get(representativeId);
+        const result = {
+          id: breakpoint.id,
+          verified: runtimeBreakpoint ? runtimeBreakpoint.verified : false,
+          line: runtimeBreakpoint && runtimeBreakpoint.line ? runtimeBreakpoint.line : breakpoint.line,
+          source: args.source,
+        };
+        if (runtimeBreakpoint && runtimeBreakpoint.message) result.message = runtimeBreakpoint.message;
+        return result;
+      }),
+    });
+  }
+
+  async stackTrace(request) {
+    if (!this.isPaused) {
+      this.sendResponse(request, { stackFrames: [], totalFrames: 0 });
+      return;
+    }
+    const { fields } = await this.runtime.request('STACK');
+    const count = Number(fields[0] || 0);
+    const stackFrames = [];
+    let cursor = 1;
+    for (let index = 0; index < count; index++) {
+      const runtimeId = Number(fields[cursor++]);
+      const name = decodeHex(fields[cursor++]);
+      const remoteFile = decodeHex(fields[cursor++]);
+      const line = Number(fields[cursor++]);
+      const column = Number(fields[cursor++]);
+      const localFile = this.toLocalPath(remoteFile);
+      const frame = {
+        id: this.toAdapterFrameId(runtimeId),
+        name: name || '<Tcl>',
+        line: line || 1,
+        column: column || 1,
+      };
+      if (localFile) frame.source = { name: path.basename(localFile), path: localFile };
+      stackFrames.push(frame);
+    }
+    this.sendResponse(request, { stackFrames, totalFrames: stackFrames.length });
+  }
+
+  async scopes(request, args) {
+    const runtimeFrameId = this.frameReferences.get(Number(args.frameId));
+    if (!this.isPaused || runtimeFrameId === undefined) {
+      this.sendResponse(request, { scopes: [] });
+      return;
+    }
+    const { fields } = await this.runtime.request('SCOPES', [runtimeFrameId]);
+    const count = Number(fields[0] || 0);
+    const scopes = [];
+    let cursor = 1;
+    for (let index = 0; index < count; index++) {
+      const variablesReference = this.toAdapterVariablesReference(Number(fields[cursor++]));
+      const name = decodeHex(fields[cursor++]);
+      cursor++; // wire label: expensive
+      const expensive = fields[cursor++] === '1';
+      scopes.push({ name, variablesReference, expensive });
+    }
+    this.sendResponse(request, { scopes });
+  }
+
+  async variables(request, args) {
+    const runtimeReference = this.variableReferences.get(Number(args.variablesReference));
+    if (!this.isPaused || runtimeReference === undefined) {
+      this.sendResponse(request, { variables: [] });
+      return;
+    }
+    const { fields } = await this.runtime.request('VARIABLES', [
+      runtimeReference,
+      args.start || 0,
+      args.count || 0,
+      encodeHex(args.filter || ''),
+    ]);
+    const count = Number(fields[0] || 0);
+    const variables = [];
+    let cursor = 1;
+    for (let index = 0; index < count; index++) {
+      variables.push({
+        name: decodeHex(fields[cursor++]),
+        value: decodeHex(fields[cursor++]),
+        type: decodeHex(fields[cursor++]),
+        variablesReference: this.toAdapterVariablesReference(Number(fields[cursor++])),
+        indexedVariables: Number(fields[cursor++]) || undefined,
+        namedVariables: Number(fields[cursor++]) || undefined,
+      });
+    }
+    this.sendResponse(request, { variables });
+  }
+
+  async evaluate(request, args) {
+    // VS Code can refresh Watch/Hover expressions after Continue but before
+    // it has processed the next stopped event. Do not forward that transient
+    // request to the running NX interpreter (which correctly rejects it).
+    if (!this.isPaused) {
+      this.sendResponse(request, {
+        result: '<NX is running; evaluation is available while paused>',
+        type: 'unavailable',
+        variablesReference: 0,
+      });
+      return;
+    }
+    let runtimeFrameId = 0;
+    if (Number(args.frameId) > 0) {
+      runtimeFrameId = this.frameReferences.get(Number(args.frameId));
+      if (runtimeFrameId === undefined) {
+        this.sendResponse(request, {
+          result: '<stack frame is no longer available>',
+          type: 'unavailable',
+          variablesReference: 0,
+        });
+        return;
+      }
+    }
+    const { fields } = await this.runtime.request('EVALUATE', [runtimeFrameId, encodeHex(args.expression || '')]);
+    this.sendResponse(request, {
+      result: decodeHex(fields[0]),
+      type: decodeHex(fields[1]),
+      variablesReference: this.toAdapterVariablesReference(Number(fields[2])),
+      indexedVariables: Number(fields[3]) || undefined,
+      namedVariables: Number(fields[4]) || undefined,
+    });
+  }
+
+  async setVariable(request, args) {
+    const runtimeReference = this.variableReferences.get(Number(args.variablesReference));
+    if (!this.isPaused || runtimeReference === undefined) {
+      throw new Error('variable is no longer available');
+    }
+    const { fields } = await this.runtime.request('SETVARIABLE', [
+      runtimeReference,
+      encodeHex(args.name),
+      encodeHex(args.value),
+    ]);
+    this.sendResponse(request, {
+      value: decodeHex(fields[0]),
+      type: decodeHex(fields[1]),
+      variablesReference: this.toAdapterVariablesReference(Number(fields[2])),
+      indexedVariables: Number(fields[3]) || undefined,
+      namedVariables: Number(fields[4]) || undefined,
+    });
+  }
+
+  async resume(request, command, responseBody = {}) {
+    this.isPaused = false;
+    this.resetStoppedReferences();
+    this.resumeInProgress++;
+    try {
+      await this.runtime.request(command);
+      // The runtime can hit the next breakpoint immediately and place its
+      // STOPPED event in the same TCP packet as this response. Always publish
+      // the DAP resume transition before releasing such a queued stop.
+      this.sendResponse(request, responseBody);
+      this.sendEvent('continued', { threadId: THREAD_ID, allThreadsContinued: true });
+    } finally {
+      this.resumeInProgress--;
+      if (this.resumeInProgress === 0) this.flushStoppedEvents();
+    }
+  }
+
+  async disconnect(request) {
+    this.explicitDisconnect = true;
+    this.isPaused = false;
+    this.resetStoppedReferences();
+    if (this.runtime && !this.runtime.closed) {
+      try {
+        await this.runtime.request('DISCONNECT', [], 2000);
+      } catch (_) {
+        // The runtime may close immediately after acknowledging detach.
+      }
+      this.runtime.close();
+    }
+    this.sendResponse(request);
+    this.sendTerminated();
+  }
+
+  onRuntimeEvent(name, fields) {
+    switch (name) {
+      case 'HELLO':
+        this.sendEvent('output', {
+          category: 'console',
+          output: `NX runtime ${decodeHex(fields[0])}, Tcl ${decodeHex(fields[1])}, PID ${fields[2]}\n`,
+        });
+        break;
+      case 'STOPPED':
+        this.isPaused = true;
+        this.resetStoppedReferences();
+        this.publishStoppedEvent({
+          reason: decodeHex(fields[0]) || 'pause',
+          threadId: THREAD_ID,
+          allThreadsStopped: true,
+          text: decodeHex(fields[3]) || undefined,
+        });
+        break;
+      case 'OUTPUT':
+        this.sendEvent('output', { category: 'stdout', output: decodeHex(fields[0]) });
+        break;
+      default:
+        this.sendEvent('output', { category: 'console', output: `NX event ${name}\n` });
+    }
+  }
+
+  publishStoppedEvent(body) {
+    if (this.resumeInProgress > 0) {
+      this.pendingStoppedEvents.push(body);
+      return;
+    }
+    this.sendEvent('stopped', body);
+  }
+
+  flushStoppedEvents() {
+    const queued = this.pendingStoppedEvents;
+    this.pendingStoppedEvents = [];
+    for (const body of queued) this.sendEvent('stopped', body);
+  }
+
+  resetStoppedReferences(resetCounters = false) {
+    this.frameReferences.clear();
+    this.runtimeToFrameReference.clear();
+    this.variableReferences.clear();
+    this.runtimeToVariableReference.clear();
+    if (resetCounters) {
+      this.nextFrameId = 1;
+      this.nextVariablesReference = 1;
+    }
+  }
+
+  toAdapterFrameId(runtimeId) {
+    const normalized = Number(runtimeId);
+    if (!Number.isFinite(normalized) || normalized <= 0) return 0;
+    let adapterId = this.runtimeToFrameReference.get(normalized);
+    if (adapterId !== undefined) return adapterId;
+    adapterId = this.nextFrameId++;
+    this.runtimeToFrameReference.set(normalized, adapterId);
+    this.frameReferences.set(adapterId, normalized);
+    return adapterId;
+  }
+
+  toAdapterVariablesReference(runtimeReference) {
+    const normalized = Number(runtimeReference);
+    if (!Number.isFinite(normalized) || normalized <= 0) return 0;
+    let adapterReference = this.runtimeToVariableReference.get(normalized);
+    if (adapterReference !== undefined) return adapterReference;
+    adapterReference = this.nextVariablesReference++;
+    this.runtimeToVariableReference.set(normalized, adapterReference);
+    this.variableReferences.set(adapterReference, normalized);
+    return adapterReference;
+  }
+
+  isTclSource(sourcePath) {
+    const extension = path.extname(String(sourcePath || '')).toLowerCase();
+    return extension === '.tcl' || extension === '.def';
+  }
+
+  breakpointSourceKey(source = {}, sourcePath = '') {
+    if (source && Number(source.sourceReference) > 0) {
+      return `reference:${source.sourceReference}`;
+    }
+    // Deliberately preserve spelling and case here: they are precisely what
+    // distinguish two VS Code source identities that map to the same runtime
+    // path. Runtime comparison is handled separately below.
+    return `path:${String(sourcePath || '')}`;
+  }
+
+  breakpointRemoteKey(remotePath) {
+    let normalized = this.normalizePath(remotePath);
+    if (process.platform === 'win32' || /^[A-Za-z]:\//.test(normalized) || normalized.startsWith('//')) {
+      normalized = normalized.toLowerCase();
+    }
+    return normalized;
+  }
+
+  breakpointSignature(breakpoint) {
+    return JSON.stringify([
+      Number(breakpoint.line),
+      breakpoint.condition || '',
+      breakpoint.hitCondition || '',
+      breakpoint.logMessage || '',
+    ]);
+  }
+
+  normalizePath(value) {
+    const normalized = String(value || '').replace(/\\/g, '/');
+    if (normalized === '/' || /^[A-Za-z]:\/$/.test(normalized)) return normalized;
+    return normalized.replace(/\/+$/, '');
+  }
+
+  samePathPrefix(candidate, prefix) {
+    let normalizedCandidate = this.normalizePath(candidate);
+    let normalizedPrefix = this.normalizePath(prefix);
+    if (process.platform === 'win32') {
+      normalizedCandidate = normalizedCandidate.toLowerCase();
+      normalizedPrefix = normalizedPrefix.toLowerCase();
+    }
+    if (normalizedCandidate === normalizedPrefix) return true;
+    const boundaryPrefix = normalizedPrefix.endsWith('/') ? normalizedPrefix : `${normalizedPrefix}/`;
+    return normalizedCandidate.startsWith(boundaryPrefix);
+  }
+
+  toRemotePath(localPath) {
+    const normalized = this.normalizePath(path.resolve(localPath || '.'));
+    const localRoot = this.normalizePath(this.localRoot);
+    if (localRoot && this.remoteRoot && this.samePathPrefix(normalized, localRoot)) {
+      return this.remoteRoot + normalized.slice(localRoot.length);
+    }
+    return normalized;
+  }
+
+  toLocalPath(remotePath) {
+    const normalized = this.normalizePath(remotePath);
+    if (this.remoteRoot && this.localRoot && this.samePathPrefix(normalized, this.remoteRoot)) {
+      const suffix = normalized.slice(this.remoteRoot.length).replace(/^\//, '');
+      return path.join(this.localRoot, ...suffix.split('/'));
+    }
+    return process.platform === 'win32' ? normalized.replace(/\//g, '\\') : normalized;
+  }
+
+  sendTerminated() {
+    if (this.terminated) return;
+    this.terminated = true;
+    this.sendEvent('terminated');
+  }
+
+  dispose() {
+    if (this.runtime) this.runtime.close();
+  }
+}
+
+if (require.main === module) {
+  new NxDebugAdapter();
+}
+
+module.exports = { NxDebugAdapter, THREAD_ID };

client/src/debugger/inlineAdapter.js

@@ -0,0 +1,68 @@
+'use strict';
+
+const { PassThrough } = require('node:stream');
+const { NxDebugAdapter } = require('./debugAdapter');
+
+function frameMessage(message) {
+  const json = JSON.stringify(message);
+  return `Content-Length: ${Buffer.byteLength(json, 'utf8')}\r\n\r\n${json}`;
+}
+
+class NxInlineDebugAdapter {
+  constructor() {
+    this.input = new PassThrough();
+    this.output = new PassThrough();
+    this.outputBuffer = Buffer.alloc(0);
+    this.listeners = new Set();
+    this.disposed = false;
+
+    this.onDidSendMessage = (listener, thisArgs, disposables) => {
+      const registration = { listener, thisArgs };
+      this.listeners.add(registration);
+      const disposable = {
+        dispose: () => this.listeners.delete(registration),
+      };
+      if (Array.isArray(disposables)) disposables.push(disposable);
+      return disposable;
+    };
+
+    this.output.on('data', (chunk) => this.onOutput(chunk));
+    this.adapter = new NxDebugAdapter(this.input, this.output);
+  }
+
+  handleMessage(message) {
+    if (!this.disposed) this.input.write(frameMessage(message));
+  }
+
+  onOutput(chunk) {
+    this.outputBuffer = Buffer.concat([this.outputBuffer, chunk]);
+    while (true) {
+      const headerEnd = this.outputBuffer.indexOf('\r\n\r\n');
+      if (headerEnd < 0) return;
+      const header = this.outputBuffer.subarray(0, headerEnd).toString('ascii');
+      const match = /Content-Length:\s*(\d+)/i.exec(header);
+      if (!match) throw new Error('missing DAP Content-Length header from NX adapter');
+      const contentLength = Number(match[1]);
+      const messageEnd = headerEnd + 4 + contentLength;
+      if (this.outputBuffer.length < messageEnd) return;
+
+      const payload = this.outputBuffer.subarray(headerEnd + 4, messageEnd).toString('utf8');
+      this.outputBuffer = this.outputBuffer.subarray(messageEnd);
+      const message = JSON.parse(payload);
+      for (const { listener, thisArgs } of [...this.listeners]) {
+        listener.call(thisArgs, message);
+      }
+    }
+  }
+
+  dispose() {
+    if (this.disposed) return;
+    this.disposed = true;
+    this.adapter.dispose();
+    this.input.end();
+    this.output.destroy();
+    this.listeners.clear();
+  }
+}
+
+module.exports = { NxInlineDebugAdapter, frameMessage };

client/src/debugger/protocol.js

@@ -0,0 +1,116 @@
+'use strict';
+
+const net = require('net');
+const { EventEmitter } = require('events');
+
+function encodeHex(value) {
+  return Buffer.from(String(value ?? ''), 'utf8').toString('hex') || '-';
+}
+
+function decodeHex(value) {
+  if (!value || value === '-') return '';
+  return Buffer.from(value, 'hex').toString('utf8');
+}
+
+class RuntimeConnection extends EventEmitter {
+  constructor() {
+    super();
+    this.socket = null;
+    this.buffer = '';
+    this.nextRequestId = 1;
+    this.pending = new Map();
+    this.closed = false;
+  }
+
+  connect(host, port) {
+    return new Promise((resolve, reject) => {
+      const socket = net.createConnection({ host, port });
+      const onError = (error) => {
+        socket.destroy();
+        reject(error);
+      };
+      socket.once('error', onError);
+      socket.once('connect', () => {
+        socket.removeListener('error', onError);
+        this.socket = socket;
+        this.closed = false;
+        socket.setEncoding('utf8');
+        socket.on('data', (chunk) => this.onData(chunk));
+        socket.on('error', (error) => this.emit('runtimeError', error));
+        socket.on('close', () => this.onClose());
+        resolve();
+      });
+    });
+  }
+
+  request(command, fields = [], timeoutMs = 30000) {
+    if (!this.socket || this.closed) {
+      return Promise.reject(new Error('NX runtime is not connected'));
+    }
+    const id = this.nextRequestId++;
+    const normalized = fields.map((field) => String(field ?? ''));
+    if (normalized.some((field) => field.includes('\t') || field.includes('\n'))) {
+      return Promise.reject(new Error('protocol fields must be hex-encoded before transmission'));
+    }
+
+    return new Promise((resolve, reject) => {
+      const timer = setTimeout(() => {
+        this.pending.delete(id);
+        reject(new Error(`NX ${command} request timed out`));
+      }, timeoutMs);
+      this.pending.set(id, { resolve, reject, timer, command });
+      this.socket.write(['REQ', id, command, ...normalized].join('\t') + '\n');
+    });
+  }
+
+  close() {
+    this.closed = true;
+    if (this.socket) this.socket.destroy();
+    this.socket = null;
+  }
+
+  onData(chunk) {
+    this.buffer += chunk;
+    let newline;
+    while ((newline = this.buffer.indexOf('\n')) >= 0) {
+      const line = this.buffer.slice(0, newline).replace(/\r$/, '');
+      this.buffer = this.buffer.slice(newline + 1);
+      if (line) this.onLine(line);
+    }
+  }
+
+  onLine(line) {
+    const fields = line.split('\t');
+    if (fields[0] === 'RES') {
+      const id = Number(fields[1]);
+      const pending = this.pending.get(id);
+      if (!pending) return;
+      this.pending.delete(id);
+      clearTimeout(pending.timer);
+      if (fields[2] === 'OK') {
+        pending.resolve({ command: fields[3], fields: fields.slice(4) });
+      } else {
+        pending.reject(new Error(decodeHex(fields[4]) || `NX ${pending.command} failed`));
+      }
+      return;
+    }
+    if (fields[0] === 'EVENT') {
+      this.emit('event', fields[1], fields.slice(2));
+      return;
+    }
+    this.emit('runtimeError', new Error(`unrecognized NX message: ${line}`));
+  }
+
+  onClose() {
+    if (this.closed) return;
+    this.closed = true;
+    for (const pending of this.pending.values()) {
+      clearTimeout(pending.timer);
+      pending.reject(new Error('NX runtime disconnected'));
+    }
+    this.pending.clear();
+    this.emit('close');
+  }
+}
+
+module.exports = { RuntimeConnection, encodeHex, decodeHex };

client/src/debugger/register.ts

@@ -0,0 +1,42 @@
+import * as vscode from "vscode"
+
+// The adapter is shared with the standalone NX Tcl Remote Debugger. It is
+// bundled by esbuild into this extension, so no child process or additional
+// VS Code extension is required.
+// eslint-disable-next-line @typescript-eslint/no-var-requires
+const { NxInlineDebugAdapter } = require("./inlineAdapter")
+
+class NxDebugAdapterFactory implements vscode.DebugAdapterDescriptorFactory {
+    createDebugAdapterDescriptor(): vscode.ProviderResult<vscode.DebugAdapterDescriptor> {
+        return new vscode.DebugAdapterInlineImplementation(new NxInlineDebugAdapter())
+    }
+}
+
+function resolveDebugConfiguration(
+    folder: vscode.WorkspaceFolder | undefined,
+    config: vscode.DebugConfiguration
+): vscode.DebugConfiguration {
+    const resolved = { ...config }
+    if (!resolved.type) resolved.type = "nx-tcl"
+    if (!resolved.request) resolved.request = "attach"
+    if (!resolved.name) resolved.name = "Attach to NX Post Tcl"
+    if (!resolved.host) resolved.host = "127.0.0.1"
+    if (!resolved.port) resolved.port = 4711
+    if (!resolved.connectTimeout) resolved.connectTimeout = 120000
+    if (resolved.stopOnEntry === undefined) resolved.stopOnEntry = false
+    if (resolved.breakOnError === undefined) resolved.breakOnError = true
+    if (!resolved.localRoot && folder) resolved.localRoot = folder.uri.fsPath
+    return resolved
+}
+
+export function registerNxTclDebugger(context: vscode.ExtensionContext): void {
+    const factory = new NxDebugAdapterFactory()
+    context.subscriptions.push(
+        vscode.debug.registerDebugAdapterDescriptorFactory("nx-tcl", factory),
+        vscode.debug.registerDebugConfigurationProvider("nx-tcl", {
+            resolveDebugConfiguration
+        })
+    )
+}
+
+export { resolveDebugConfiguration }

client/src/extension.ts

@@ -29,10 +29,13 @@ import { checkIfConfigurationChanged, getInterpreterFromSetting } from "./common
 import { loadServerDefaults } from "./common/setup"
 import { getLSClientTraceLevel } from "./common/utilities"
 import { createOutputChannel, onDidChangeConfiguration, registerCommand } from "./common/vscodeapi"
+import { registerNxTclDebugger } from "./debugger/register"
 
 let client: LanguageClient | undefined
 
 export async function activate(context: vscode.ExtensionContext) {
+    registerNxTclDebugger(context)
+
     // This is required to get server name and module. This should be
     // the first thing that we do in this extension.
     const serverInfo = loadServerDefaults()

debugger/NX_TCL_DEBUGGER_LICENSE.txt

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2026 NX Tcl Remote Debugger contributors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "nx-post-support",
-  "version": "2025.9.200",
+  "version": "2026.8.201",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "nx-post-support",
-      "version": "2025.9.200",
+      "version": "2026.8.201",
       "devDependencies": {
         "@types/vscode": "^1.96.0",
         "@vscode/vsce": "^3.2.1",

package.json

@@ -1,10 +1,16 @@
 {
   "name": "nx-post-support",
   "displayName": "NX Postprocessor Support",
-  "description": "VS Code extension for NX CAM postprocessor development with syntax highlighting, formatting, linting, and auto-completion for CDL, TCL, and DEF files",
-  "version": "2026.8.100",
+  "description": "VS Code extension for NX CAM postprocessor development with language support and remote Tcl debugging for CDL, TCL, and DEF files",
+  "version": "2026.8.201",
   "publisher": "Christoph",
   "icon": "images/nx-1.png",
+  "activationEvents": [
+    "onLanguage:tcl",
+    "onLanguage:cdl",
+    "onLanguage:def",
+    "onDebug"
+  ],
   "extensionDependencies": [
     "ms-python.python"
   ],
@@ -23,15 +29,109 @@
     "UDE",
     "Postprocessor",
     "NX CAM",
-    "Siemens NX"
+    "Siemens NX",
+    "debugger",
+    "remote debugging"
   ],
   "engines": {
     "vscode": "^1.96.0"
   },
   "categories": [
-    "Programming Languages"
+    "Programming Languages",
+    "Debuggers"
   ],
   "contributes": {
+    "breakpoints": [
+      {
+        "language": "tcl"
+      },
+      {
+        "language": "def"
+      }
+    ],
+    "debuggers": [
+      {
+        "type": "nx-tcl",
+        "label": "NX Tcl Remote Debugger",
+        "languages": [
+          "tcl",
+          "def"
+        ],
+        "configurationAttributes": {
+          "attach": {
+            "required": [
+              "host",
+              "port"
+            ],
+            "properties": {
+              "host": {
+                "type": "string",
+                "default": "127.0.0.1",
+                "description": "Host on which the NX Tcl runtime is listening."
+              },
+              "port": {
+                "type": "number",
+                "default": 4711,
+                "description": "TCP port of the NX Tcl runtime."
+              },
+              "connectTimeout": {
+                "type": "number",
+                "default": 120000,
+                "description": "How long VS Code retries until NX starts the runtime, in milliseconds."
+              },
+              "stopOnEntry": {
+                "type": "boolean",
+                "default": false,
+                "description": "Stop on the first traced Tcl command."
+              },
+              "breakOnError": {
+                "type": "boolean",
+                "default": true,
+                "description": "Stop when a traced Tcl command returns TCL_ERROR."
+              },
+              "localRoot": {
+                "type": "string",
+                "description": "Local source root opened in VS Code."
+              },
+              "remoteRoot": {
+                "type": "string",
+                "description": "Corresponding source root on the NX host when it differs from localRoot."
+              }
+            }
+          }
+        },
+        "initialConfigurations": [
+          {
+            "type": "nx-tcl",
+            "request": "attach",
+            "name": "Attach to NX Post Tcl",
+            "host": "127.0.0.1",
+            "port": 4711,
+            "connectTimeout": 120000,
+            "stopOnEntry": false,
+            "breakOnError": true,
+            "localRoot": "${workspaceFolder}"
+          }
+        ],
+        "configurationSnippets": [
+          {
+            "label": "NX Tcl: Attach to NX Post",
+            "description": "Attach VS Code to an NX runtime embedded in NX Post.",
+            "body": {
+              "type": "nx-tcl",
+              "request": "attach",
+              "name": "Attach to NX Post Tcl",
+              "host": "127.0.0.1",
+              "port": 4711,
+              "connectTimeout": 120000,
+              "stopOnEntry": false,
+              "breakOnError": true,
+              "localRoot": "${workspaceFolder}"
+            }
+          }
+        ]
+      }
+    ],
     "languages": [
       {
         "id": "tcl",
@@ -151,7 +251,8 @@
     "compile": "node esbuild.js --production",
     "compile:debug": "node esbuild.js",
     "watch": "node esbuild.js --watch",
-    "package": "node esbuild.js --production"
+    "package": "node esbuild.js --production",
+    "test:debugger": "node --test test/debugger.test.js"
   },
   "devDependencies": {
     "@types/vscode": "^1.96.0",

test/debugger.test.js

@@ -0,0 +1,63 @@
+"use strict"
+
+const test = require("node:test")
+const assert = require("node:assert/strict")
+const { PassThrough } = require("node:stream")
+const { NxDebugAdapter } = require("../client/src/debugger/debugAdapter")
+const manifest = require("../package.json")
+
+function dapMessage(message) {
+    const json = JSON.stringify(message)
+    return `Content-Length: ${Buffer.byteLength(json, "utf8")}\r\n\r\n${json}`
+}
+
+function readDapMessage(stream) {
+    return new Promise((resolve, reject) => {
+        let buffer = Buffer.alloc(0)
+        const timer = setTimeout(() => reject(new Error("DAP response timed out")), 2000)
+        const onData = (chunk) => {
+            buffer = Buffer.concat([buffer, chunk])
+            const headerEnd = buffer.indexOf("\r\n\r\n")
+            if (headerEnd < 0) return
+            const header = buffer.subarray(0, headerEnd).toString("ascii")
+            const match = /Content-Length:\s*(\d+)/i.exec(header)
+            if (!match) return
+            const length = Number(match[1])
+            if (buffer.length < headerEnd + 4 + length) return
+            clearTimeout(timer)
+            stream.removeListener("data", onData)
+            resolve(JSON.parse(buffer.subarray(headerEnd + 4, headerEnd + 4 + length)))
+        }
+        stream.on("data", onData)
+    })
+}
+
+test("integrated manifest contributes the NX Tcl debugger", () => {
+    const debuggerContribution = manifest.contributes.debuggers.find(
+        (entry) => entry.type === "nx-tcl"
+    )
+    assert.ok(debuggerContribution)
+    assert.deepEqual(debuggerContribution.languages, ["tcl", "def"])
+    assert.deepEqual(
+        manifest.contributes.breakpoints.map((entry) => entry.language),
+        ["tcl", "def"]
+    )
+})
+
+test("integrated adapter answers a DAP initialize request", async () => {
+    const input = new PassThrough()
+    const output = new PassThrough()
+    const adapter = new NxDebugAdapter(input, output)
+    const responsePromise = readDapMessage(output)
+
+    input.write(
+        dapMessage({ seq: 1, type: "request", command: "initialize", arguments: {} })
+    )
+    const response = await responsePromise
+    adapter.dispose()
+
+    assert.equal(response.success, true)
+    assert.equal(response.command, "initialize")
+    assert.equal(response.body.supportsConfigurationDoneRequest, true)
+    assert.equal(response.body.supportsSetVariable, true)
+})