[UPDATE PRIMITIVE] Add MCP prompt argument completions for VS Code slash command UX

extensions/vscode/esbuild.config.js

@@ -37,6 +37,7 @@ const testSuiteConfig = {
     'test/suite/bridge.integration.test.ts',
     'test/suite/copydb-e2e.integration.test.ts',
     'test/suite/extension.integration.test.ts',
+    'test/suite/mcp-completion-e2e.integration.test.ts',
     'test/suite/mcp-prompt-e2e.integration.test.ts',
     'test/suite/mcp-resource-e2e.integration.test.ts',
     'test/suite/mcp-server.integration.test.ts',

extensions/vscode/src/codeql/cli-resolver.ts

@@ -32,6 +32,7 @@ const KNOWN_LOCATIONS = [
 export class CliResolver extends DisposableObject {
   private cachedPath: string | undefined | null = null; // null = not yet resolved
   private cachedVersion: string | undefined;
+  private resolvePromise: Promise<string | undefined> | null = null;
 
   constructor(
     private readonly logger: Logger,
@@ -57,6 +58,21 @@ export class CliResolver extends DisposableObject {
       return this.cachedPath;
     }
 
+    // Return the in-flight promise if a resolution is already in progress
+    if (this.resolvePromise) {
+      return this.resolvePromise;
+    }
+
+    this.resolvePromise = this.doResolve();
+    try {
+      return await this.resolvePromise;
+    } finally {
+      this.resolvePromise = null;
+    }
+  }
+
+  /** Internal resolution logic. Called at most once per cache cycle. */
+  private async doResolve(): Promise<string | undefined> {
     this.logger.debug('Resolving CodeQL CLI path...');
 
     // Strategy 1: CODEQL_PATH env var
@@ -74,9 +90,13 @@ export class CliResolver extends DisposableObject {
     // Strategy 2: which/command -v
     const whichPath = await this.resolveFromPath();
     if (whichPath) {
-      this.logger.info(`CodeQL CLI found on PATH: ${whichPath}`);
-      this.cachedPath = whichPath;
-      return whichPath;
+      const validated = await this.validateBinary(whichPath);
+      if (validated) {
+        this.logger.info(`CodeQL CLI found on PATH: ${whichPath}`);
+        this.cachedPath = whichPath;
+        return whichPath;
+      }
+      this.logger.warn(`Found 'codeql' on PATH at '${whichPath}' but it failed validation.`);
     }
 
     // Strategy 3: vscode-codeql managed distribution
@@ -106,6 +126,7 @@ export class CliResolver extends DisposableObject {
   invalidateCache(): void {
     this.cachedPath = null;
     this.cachedVersion = undefined;
+    this.resolvePromise = null;
   }
 
   /** Check if a path exists and responds to `--version`. */

extensions/vscode/src/server/pack-installer.ts

@@ -153,10 +153,21 @@ export class PackInstaller extends DisposableObject {
     const actualCliVersion = this.cliResolver.getCliVersion();
     const targetCliVersion = this.getTargetCliVersion();
 
+    if (actualCliVersion) {
+      this.logger.info(
+        `Detected CodeQL CLI version: ${actualCliVersion}, target: ${targetCliVersion}.`,
+      );
+    } else {
+      this.logger.info(
+        `CodeQL CLI version could not be determined. Target: ${targetCliVersion}. ` +
+        'Using bundled pack install.',
+      );
+    }
+
     if (downloadEnabled && actualCliVersion && actualCliVersion !== targetCliVersion) {
       this.logger.info(
         `CodeQL CLI version ${actualCliVersion} differs from VSIX target ${targetCliVersion}. ` +
-        'Attempting to download compatible tool query packs...',
+        'Attempting to install compatible tool query packs...',
       );
       const downloaded = await this.downloadPacksForCliVersion(
         codeqlPath, actualCliVersion, languages,
@@ -165,7 +176,11 @@ export class PackInstaller extends DisposableObject {
         return;
       }
       this.logger.info(
-        'Pack download did not succeed for all languages — falling back to bundled pack install.',
+        'Pack install did not succeed for all languages — falling back to bundled pack install.',
+      );
+    } else if (actualCliVersion && actualCliVersion === targetCliVersion) {
+      this.logger.info(
+        `CLI and target versions match (${actualCliVersion}). Using bundled pack install.`,
       );
     }
 
@@ -195,24 +210,29 @@ export class PackInstaller extends DisposableObject {
     }
 
     this.logger.info(
-      `Downloading ql-mcp tool query packs v${packVersion} for CodeQL CLI ${cliVersion}...`,
+      `Installing ql-mcp tool query packs v${packVersion} for CodeQL CLI ${cliVersion}...`,
     );
 
     let allSucceeded = true;
+    let successCount = 0;
     for (const lang of languages) {
       const packRef =
         `${PackInstaller.PACK_SCOPE}/ql-mcp-${lang}-tools-src@${packVersion}`;
-      this.logger.info(`Downloading ${packRef}...`);
+      this.logger.info(`Installing ${packRef}...`);
       try {
         await this.runCodeqlPackDownload(codeqlPath, packRef);
-        this.logger.info(`Downloaded ${packRef}.`);
+        this.logger.info(`Installed ${packRef}.`);
+        successCount++;
       } catch (err) {
         this.logger.error(
-          `Failed to download ${packRef}: ${err instanceof Error ? err.message : String(err)}`,
+          `Failed to install ${packRef}: ${err instanceof Error ? err.message : String(err)}`,
         );
         allSucceeded = false;
       }
     }
+    this.logger.info(
+      `Pack install complete: ${successCount}/${languages.length} languages succeeded.`,
+    );
     return allSucceeded;
   }
 
@@ -226,9 +246,11 @@ export class PackInstaller extends DisposableObject {
     languages: string[],
   ): Promise<void> {
     const qlRoot = this.getQlpackRoot();
+    let successCount = 0;
 
     for (const lang of languages) {
       const packDir = join(qlRoot, 'ql', lang, 'tools', 'src');
+      const packName = `${PackInstaller.PACK_SCOPE}/ql-mcp-${lang}-tools-src`;
 
       // Check if the pack directory exists
       try {
@@ -238,16 +260,20 @@ export class PackInstaller extends DisposableObject {
         continue;
       }
 
-      this.logger.info(`Installing CodeQL pack dependencies for ${lang}...`);
+      this.logger.info(`Installing CodeQL pack dependencies for ${packName} (${lang})...`);
       try {
         await this.runCodeqlPackInstall(codeqlPath, packDir);
-        this.logger.info(`Pack dependencies installed for ${lang}.`);
+        this.logger.info(`Pack dependencies installed for ${packName} (${lang}).`);
+        successCount++;
       } catch (err) {
         this.logger.error(
           `Failed to install pack dependencies for ${lang}: ${err instanceof Error ? err.message : String(err)}`,
         );
       }
     }
+    this.logger.info(
+      `Bundled pack install complete: ${successCount}/${languages.length} languages succeeded.`,
+    );
   }
 
   /** Run `codeql pack install` for a single pack directory. */

extensions/vscode/src/server/server-manager.ts

@@ -124,8 +124,7 @@ export class ServerManager extends DisposableObject {
     // VSIX bundle or monorepo server is present — no npm install required.
     if (this.getBundledQlRoot()) {
       this.logger.info(
-        `Using bundled server (v${this.getExtensionVersion()}). ` +
-        'No npm install required.',
+        `Bundled server ready (v${this.getExtensionVersion()}).`,
       );
       return false;
     }

extensions/vscode/test/codeql/cli-resolver.test.ts

@@ -434,4 +434,121 @@ describe('CliResolver', () => {
       expect(result).toBe(expectedPath);
     });
   });
+
+  describe('PATH resolution version detection', () => {
+    let originalEnv: string | undefined;
+
+    beforeEach(() => {
+      originalEnv = process.env.CODEQL_PATH;
+      delete process.env.CODEQL_PATH;
+    });
+
+    afterEach(() => {
+      if (originalEnv === undefined) {
+        delete process.env.CODEQL_PATH;
+      } else {
+        process.env.CODEQL_PATH = originalEnv;
+      }
+    });
+
+    it('should detect CLI version when resolved via PATH', async () => {
+      // `which codeql` succeeds, then `codeql --version` returns version
+      vi.mocked(execFile).mockImplementation(
+        (_cmd: any, _args: any, callback: any) => {
+          const cmd = String(_cmd);
+          const args = Array.isArray(_args) ? _args : [];
+          if (cmd === 'which' || cmd === 'where') {
+            callback(null, '/usr/local/bin/codeql\n', '');
+          } else if (args.includes('--version')) {
+            callback(null, 'CodeQL CLI 2.24.1\n', '');
+          }
+          return {} as any;
+        },
+      );
+
+      vi.mocked(access).mockResolvedValue(undefined as any);
+
+      const result = await resolver.resolve();
+      expect(result).toBe('/usr/local/bin/codeql');
+      expect(resolver.getCliVersion()).toBe('2.24.1');
+    });
+
+    it('should fall through when PATH binary fails validation', async () => {
+      // `which codeql` returns a path, but --version fails
+      vi.mocked(execFile).mockImplementation(
+        (_cmd: any, _args: any, callback: any) => {
+          const cmd = String(_cmd);
+          if (cmd === 'which' || cmd === 'where') {
+            callback(null, '/broken/codeql\n', '');
+          } else {
+            callback(new Error('not a valid binary'), '', '');
+          }
+          return {} as any;
+        },
+      );
+
+      // access fails for everything (including known locations)
+      vi.mocked(access).mockRejectedValue(new Error('ENOENT'));
+
+      const result = await resolver.resolve();
+      expect(result).toBeUndefined();
+      expect(resolver.getCliVersion()).toBeUndefined();
+    });
+  });
+
+  describe('concurrent resolution', () => {
+    let originalEnv: string | undefined;
+
+    beforeEach(() => {
+      originalEnv = process.env.CODEQL_PATH;
+      process.env.CODEQL_PATH = '/usr/local/bin/codeql';
+    });
+
+    afterEach(() => {
+      if (originalEnv === undefined) {
+        delete process.env.CODEQL_PATH;
+      } else {
+        process.env.CODEQL_PATH = originalEnv;
+      }
+    });
+
+    it('should not duplicate resolution work for concurrent calls', async () => {
+      vi.mocked(access).mockResolvedValue(undefined as any);
+      vi.mocked(execFile).mockImplementation(
+        (_cmd: any, _args: any, callback: any) => {
+          callback(null, 'CodeQL CLI 2.25.1\n', '');
+          return {} as any;
+        },
+      );
+
+      // Fire two concurrent resolve() calls
+      const [result1, result2] = await Promise.all([
+        resolver.resolve(),
+        resolver.resolve(),
+      ]);
+
+      expect(result1).toBe('/usr/local/bin/codeql');
+      expect(result2).toBe('/usr/local/bin/codeql');
+      // Should only validate once, not twice
+      expect(access).toHaveBeenCalledTimes(1);
+    });
+
+    it('should allow re-resolution after invalidateCache', async () => {
+      vi.mocked(access).mockResolvedValue(undefined as any);
+      vi.mocked(execFile).mockImplementation(
+        (_cmd: any, _args: any, callback: any) => {
+          callback(null, 'CodeQL CLI 2.25.1\n', '');
+          return {} as any;
+        },
+      );
+
+      await resolver.resolve();
+      resolver.invalidateCache();
+
+      const result = await resolver.resolve();
+      expect(result).toBe('/usr/local/bin/codeql');
+      // access called twice: once before invalidation, once after
+      expect(access).toHaveBeenCalledTimes(2);
+    });
+  });
 });