Add PowerShell language model tools and redesign the Command Explorer

.github/copilot-instructions.md

@@ -40,10 +40,25 @@ extensions.
 
 ### PSES and Cross-Repo Work
 
-The `modules/` folder contains the PSES, PSReadLine, and PSScriptAnalyzer PowerShell modules. In development it is a
-symlink to `../PowerShellEditorServices/module` — [PowerShellEditorServices][] must be
+The `modules/` folder contains the PSES, PSReadLine, and PSScriptAnalyzer PowerShell modules. In development the whole
+folder is a symlink to `../PowerShellEditorServices/module` — [PowerShellEditorServices][] must be
 cloned as a sibling and built before `npm run compile` will succeed. For cross-repo work, use `pwsh-extension-dev.code-workspace`.
 
+**Cross-repo dev/test cycle.** Because `modules/` is a symlink into the sibling PSES checkout's
+`module/` directory, building PSES deploys its DLLs straight into the path the extension loads from —
+there is no copy step:
+
+- **Edit PSES C# (server)** → rebuild PSES (e.g. `dotnet build src/PowerShellEditorServices/PowerShellEditorServices.csproj`,
+  or `Invoke-Build Build` for a full build). The build deploys into `module/PowerShellEditorServices/bin`,
+  which the symlinked `modules/` exposes to the extension automatically. The extension (and its tests)
+  then load the new DLL — no copy, but you must rebuild PSES, since the extension does not.
+- **Edit extension TypeScript (client)** → `npm run compile`.
+- **Verify end-to-end** → `npm test`. This launches a real VS Code Extension Host with PSES connected
+  and runs the Mocha suite, exercising the locally-built PSES through the symlink. Prefer this over
+  only eyeballing the Extension Development Host: it is the way to confirm cross-repo (client + server)
+  changes actually work, and to catch regressions. After changing a setting's default or any shared
+  behavior, run the full suite — e.g. ISE-compatibility tests assert against setting defaults.
+
 ## Key Conventions
 
 - **VS Code best practices**: Follow the [Extension Guidelines](https://code.visualstudio.com/api/references/extension-guidelines) and [UX Guidelines](https://code.visualstudio.com/api/ux-guidelines/overview). Use VS Code's APIs idiomatically and prefer disposable patterns for lifecycle management.

.github/workflows/ci-test.yml

@@ -28,6 +28,9 @@ jobs:
         uses: actions/checkout@v6
         with:
           repository: PowerShell/PowerShellEditorServices
+          # TEMPORARY: test against the coupled PSES PR #2298 until it merges.
+          # Revert this `ref` before merging (see PR #5508).
+          ref: andyleejordan/lm-tools-command-explorer
           path: PowerShellEditorServices
 
       - name: Checkout vscode-powershell

.vscode-test.mjs

@@ -1,5 +1,7 @@
 import { defineConfig } from "@vscode/test-cli";
 import { existsSync } from "fs";
+import { tmpdir } from "os";
+import { join } from "path";
 
 export default defineConfig({
     files: "test/**/*.test.ts",
@@ -10,6 +12,12 @@ export default defineConfig({
         "--disable-extensions",
         // Undocumented but valid option to use a temporary profile for testing
         "--profile-temp",
+        // The default user-data-dir lives under the (deeply nested on CI)
+        // workspace path, and its IPC socket blows past macOS's 104-char
+        // unix-socket limit, causing a flaky `listen EINVAL`. Anchor it in the
+        // OS temp dir so the socket path stays short on every platform.
+        "--user-data-dir",
+        join(tmpdir(), "vscode-powershell-test"),
     ],
     workspaceFolder: `test/${existsSync("C:\\powershell-7\\pwsh.exe") ? "OneBranch" : "TestEnvironment"}.code-workspace`,
     mocha: {

package.json

@@ -125,6 +125,97 @@
         "language": "powershell"
       }
     ],
+    "languageModelTools": [
+      {
+        "name": "powershell_get_command",
+        "toolReferenceName": "getPowerShellCommand",
+        "displayName": "Get PowerShell Command",
+        "modelDescription": "Get the commands (cmdlets, functions, and scripts) available in the user's active PowerShell session, scoped by name and/or module. You must provide a 'name' and/or 'module' filter (at least one is required). Returns each matching command's name, module, default parameter set, and parameter names. Use this to discover the exact name, module, and parameters of a PowerShell command instead of guessing.",
+        "userDescription": "Lists commands available in the active PowerShell session.",
+        "canBeReferencedInPrompt": true,
+        "icon": "$(symbol-method)",
+        "tags": [
+          "powershell"
+        ],
+        "inputSchema": {
+          "type": "object",
+          "properties": {
+            "name": {
+              "type": "string",
+              "description": "Only return commands whose name matches this value (supports wildcards; bare text is matched as a substring), e.g. 'Get-ChildItem', 'ChildItem', or 'Get-*'. Provide this and/or 'module'."
+            },
+            "module": {
+              "type": "string",
+              "description": "Only return commands from this module (supports wildcards), e.g. 'Microsoft.PowerShell.Management'. Provide this and/or 'name'."
+            }
+          }
+        }
+      },
+      {
+        "name": "powershell_get_help",
+        "toolReferenceName": "getPowerShellHelp",
+        "displayName": "Get PowerShell Help",
+        "modelDescription": "Get the full help (Get-Help -Full) for a specific PowerShell command from the user's active session, including synopsis, syntax, parameter descriptions, and examples. Use this to ground answers about how a PowerShell command works and what parameters it accepts, instead of guessing.",
+        "userDescription": "Retrieves the full help for a PowerShell command.",
+        "canBeReferencedInPrompt": true,
+        "icon": "$(question)",
+        "tags": [
+          "powershell"
+        ],
+        "inputSchema": {
+          "type": "object",
+          "properties": {
+            "command": {
+              "type": "string",
+              "description": "The name of the PowerShell command to get help for, e.g. 'Get-ChildItem'."
+            }
+          },
+          "required": [
+            "command"
+          ]
+        }
+      },
+      {
+        "name": "powershell_get_environment",
+        "toolReferenceName": "getPowerShellEnvironment",
+        "displayName": "Get PowerShell Environment",
+        "modelDescription": "Get details about the user's active PowerShell session, including the PowerShell version, edition (Core or Desktop), and process architecture. Use this before constructing version- or edition-specific PowerShell so that suggestions match the user's actual environment.",
+        "userDescription": "Reports the active PowerShell version, edition, and architecture.",
+        "canBeReferencedInPrompt": true,
+        "icon": "$(terminal-powershell)",
+        "tags": [
+          "powershell"
+        ],
+        "inputSchema": {
+          "type": "object",
+          "properties": {}
+        }
+      },
+      {
+        "name": "powershell_expand_alias",
+        "toolReferenceName": "expandPowerShellAlias",
+        "displayName": "Expand PowerShell Aliases",
+        "modelDescription": "Expand the aliases in a PowerShell script to their full command names (for example 'gci' becomes 'Get-ChildItem' and '?' becomes 'Where-Object') using the user's active PowerShell session. Use this to normalize or clarify aliased PowerShell before explaining or editing it.",
+        "userDescription": "Expands aliases in a PowerShell script to full command names.",
+        "canBeReferencedInPrompt": true,
+        "icon": "$(symbol-string)",
+        "tags": [
+          "powershell"
+        ],
+        "inputSchema": {
+          "type": "object",
+          "properties": {
+            "text": {
+              "type": "string",
+              "description": "The PowerShell script text whose aliases should be expanded."
+            }
+          },
+          "required": [
+            "text"
+          ]
+        }
+      }
+    ],
     "viewsContainers": {
       "activitybar": [
         {
@@ -391,12 +482,12 @@
       "view/item/context": [
         {
           "command": "PowerShell.ShowHelp",
-          "when": "view == PowerShellCommands",
+          "when": "view == PowerShellCommands && viewItem == command",
           "group": "inline@1"
         },
         {
           "command": "PowerShell.InsertCommand",
-          "when": "view == PowerShellCommands",
+          "when": "view == PowerShellCommands && viewItem == command",
           "group": "inline@2"
         }
       ]
@@ -748,7 +839,7 @@
           },
           "powershell.sideBar.CommandExplorerVisibility": {
             "type": "boolean",
-            "default": false,
+            "default": true,
             "markdownDescription": "Specifies the visibility of the Command Explorer in the side bar."
           },
           "powershell.sideBar.CommandExplorerExcludeFilter": {

src/extension.ts

@@ -20,6 +20,7 @@ import {
 import { GetCommandsFeature } from "./features/GetCommands";
 import { HelpCompletionFeature } from "./features/HelpCompletion";
 import { ISECompatibilityFeature } from "./features/ISECompatibility";
+import { LanguageModelToolsFeature } from "./features/LanguageModelTools";
 import { OpenInISEFeature } from "./features/OpenInISE";
 import { PesterTestsFeature } from "./features/PesterTests";
 import { RemoteFilesFeature } from "./features/RemoteFiles";
@@ -193,6 +194,7 @@ export async function activate(
         new RemoteFilesFeature(),
         new DebugSessionFeature(context, sessionManager, logger),
         new HelpCompletionFeature(),
+        new LanguageModelToolsFeature(),
     ];
 
     sessionManager.setLanguageClientConsumers(languageClientConsumers);