add Explain Code / Generate Tests code lenses

.changeset/vscode-code-lens-actions.md

@@ -0,0 +1,5 @@
+---
+"@nanocollective/nanocoder": minor
+---
+
+Added editor code lenses to the VS Code extension: every function, method, constructor and class now carries `Explain Code` and `Generate Tests` links, and clicking one reveals the chat view and sends that symbol - instruction, `file:startLine-endLine` and the source, fenced with the document language - as a prompt. Symbols come from the language server, so no per-language parsing is involved, and the lenses can be turned off with `nanocoder.codeLens`. Long symbols are capped before being inlined, so a lens click on a large class cannot spend a whole context window on one turn. Also fixes a pre-existing hang where sending a message while a tool approval was still pending left the composer spinning forever. Closes #750.

plugins/vscode/.vscodeignore

@@ -1,6 +1,7 @@
 .vscode/**
 .vscode-test/**
 src/**
+test-stubs/**
 node_modules/**
 .gitignore
 tsconfig.json

plugins/vscode/README.md

@@ -14,6 +14,7 @@ The extension provides a native sidebar chat powered by the Agent Client Protoco
 - **Task Checklist**: The AI's task list renders as a live checklist card with per-task status and progress
 - **Cancellation**: Stop ends the whole turn - the current tool aborts and queued tools are skipped
 - **Diff Previews**: Click a file-edit card to open the change in VS Code's diff viewer
+- **Editor Code Lenses**: `Explain Code` and `Generate Tests` links above every function, method, constructor and class - clicking one opens the chat and sends that symbol as context
 - **Legacy Companion Mode** (opt-in): Pairs with a terminal CLI session over WebSocket for diff previews and editor context
 
 ## Installation
@@ -126,6 +127,7 @@ Configure the extension in VS Code settings (`Ctrl+,` / `Cmd+,`):
 | `nanocoder.mode`            | `auto-accept` | Operating mode for the assistant                                      |
 | `nanocoder.model`           | (empty)       | Model for Nanocoder sessions (set via the model dropdown)             |
 | `nanocoder.showDiffPreview` | `true`        | Show diff preview before applying file changes                        |
+| `nanocoder.codeLens`        | `true`        | Show Explain Code / Generate Tests lenses above functions and classes  |
 | `nanocoder.autoConnect`     | `false`       | Auto-connect the legacy WebSocket companion on startup                |
 | `nanocoder.autoStartCli`    | `false`       | Auto-start the CLI for companion mode if not running                  |
 | `nanocoder.serverPort`      | `51820`       | WebSocket port for the legacy companion mode                          |

plugins/vscode/media/chat-panel.js

@@ -818,13 +818,6 @@
 
 		const imagesToSubmit = pendingImages.length > 0 ? [...pendingImages] : undefined;
 
-		// Send message to extension host
-		vscode.postMessage({
-			type: 'submitMessage',
-			text: text,
-			images: imagesToSubmit
-		});
-
 		// Clear input. Close the mention first — its token offsets point into
 		// text that is about to disappear.
 		closeMention();
@@ -837,8 +830,23 @@
 		attachedPaths = [];
 		renderChips();
 
+		dispatchPrompt(text, imagesToSubmit);
+	}
+
+	// Send `text` to the agent as a turn of its own. Split out of
+	// submitMessage so an editor-driven prompt can bypass the composer: going
+	// through it would overwrite a draft the user is typing and sweep up chips
+	// and images they staged for a different question.
+	function dispatchPrompt(text, images) {
+		// Send message to extension host
+		vscode.postMessage({
+			type: 'submitMessage',
+			text: text,
+			images: images
+		});
+
 		// Optimistically append user message
-		appendMessage(text, 'user', imagesToSubmit);
+		appendMessage(text, 'user', images);
 		pendingUserMessageText = text;
 
 		if (!isProcessing) {
@@ -1474,6 +1482,11 @@
 				sessionsData = message.sessions || [];
 				renderSessions(); // Always update so list is ready when history opens
 				break;
+			case 'runPrompt':
+				if (isHistoryView) showChatView();
+				dispatchPrompt(message.text);
+				chatInput.focus();
+				break;
 			case 'copyLastCodeBlock':
 				copyLastCodeBlock();
 				break;

plugins/vscode/package.json

@@ -91,6 +91,16 @@
 				"command": "nanocoder.copyLastCodeBlock",
 				"title": "Copy Last Code Block",
 				"category": "Nanocoder"
+			},
+			{
+				"command": "nanocoder.explainCode",
+				"title": "Explain Code",
+				"category": "Nanocoder"
+			},
+			{
+				"command": "nanocoder.generateTests",
+				"title": "Generate Tests",
+				"category": "Nanocoder"
 			}
 		],
 		"keybindings": [
@@ -113,6 +123,16 @@
 					"when": "view == nanocoder.chatView",
 					"group": "navigation@2"
 				}
+			],
+			"commandPalette": [
+				{
+					"command": "nanocoder.explainCode",
+					"when": "false"
+				},
+				{
+					"command": "nanocoder.generateTests",
+					"when": "false"
+				}
 			]
 		},
 		"configuration": {
@@ -158,6 +178,12 @@
 					"type": "string",
 					"scope": "resource",
 					"description": "Working directory for the Nanocoder CLI. Defaults to the current VS Code workspace root."
+				},
+				"nanocoder.codeLens": {
+					"type": "boolean",
+					"default": true,
+					"scope": "resource",
+					"description": "Show Explain Code / Generate Tests actions above functions and classes in the editor."
 				}
 			}
 		}

plugins/vscode/src/chat-webview-provider.ts

@@ -22,11 +22,23 @@ const MENTION_ALWAYS_EXCLUDE = [
 	'**/coverage/**',
 ];
 
-export class ChatWebviewProvider implements vscode.WebviewViewProvider {
+/**
+ * How long an editor-driven prompt waits for the webview shell and the ACP
+ * session before it is dropped. Without a bound, a prompt queued while the CLI
+ * is down would fire whenever the connection eventually came up - long after
+ * the user moved on from the code they clicked.
+ */
+const PENDING_PROMPT_TIMEOUT_MS = 30_000;
+
+export class ChatWebviewProvider
+	implements vscode.WebviewViewProvider, vscode.Disposable {
 	public static readonly viewType = 'nanocoder.chatView';
 
 	private _view?: vscode.WebviewView;
 	private _isWebviewReady = false;
+	/** Code lens prompt waiting on the webview shell and the ACP session. */
+	private _pendingPrompt: string | null = null;
+	private _pendingPromptTimer: ReturnType<typeof setTimeout> | null = null;
 
 	constructor(
 		private readonly _extensionUri: vscode.Uri,
@@ -91,6 +103,58 @@ export class ChatWebviewProvider implements vscode.WebviewViewProvider {
 		}
 	}
 
+	/**
+	 * Reveal the chat view and run `text` as a prompt. An editor code lens can
+	 * fire long before the sidebar has ever been opened, so the prompt is held
+	 * until the shell reports ready and a session exists.
+	 */
+	public async sendPrompt(text: string) {
+		this._queuePendingPrompt(text);
+		await vscode.commands.executeCommand(`${ChatWebviewProvider.viewType}.focus`);
+		await this._initializeSessionIfReady();
+	}
+
+	private _queuePendingPrompt(text: string) {
+		this._clearPendingPrompt();
+		this._pendingPrompt = text;
+		this._pendingPromptTimer = setTimeout(() => {
+			this._pendingPromptTimer = null;
+			this._pendingPrompt = null;
+			vscode.window.showWarningMessage(
+				'Nanocoder: the agent did not start in time, so your editor request was not sent. Try again once the chat view is connected.',
+			);
+		}, PENDING_PROMPT_TIMEOUT_MS);
+	}
+
+	private _clearPendingPrompt() {
+		if (this._pendingPromptTimer) {
+			clearTimeout(this._pendingPromptTimer);
+			this._pendingPromptTimer = null;
+		}
+		this._pendingPrompt = null;
+	}
+
+	/**
+	 * Hand a queued prompt to the webview. Cleared before posting so a failed
+	 * delivery can't be retried into a half-loaded shell.
+	 */
+	private _flushPendingPrompt() {
+		const text = this._pendingPrompt;
+		if (text === null) {
+			return;
+		}
+		this._clearPendingPrompt();
+		this.postMessage({type: 'runPrompt', text});
+	}
+
+	/**
+	 * Registered with the extension's subscriptions so a deactivate cannot
+	 * leave the pending-prompt timer running against a disposed view.
+	 */
+	public dispose() {
+		this._clearPendingPrompt();
+	}
+
 	public requestCopyLastCodeBlock() {
 		if (!this._view) {
 			vscode.window.showInformationMessage('Nanocoder: open the Nanocoder chat view first.');
@@ -111,6 +175,23 @@ export class ChatWebviewProvider implements vscode.WebviewViewProvider {
 		_token: vscode.CancellationToken,
 	) {
 		this._view = webviewView;
+		// A re-resolve means a brand new shell that has not run its script yet.
+		// Leaving the flag set from the previous one would let a queued prompt
+		// post into a webview with no message listener attached, dropping it.
+		this._isWebviewReady = false;
+		webviewView.onDidDispose(() => {
+			// A disposal can land after a newer view has already been resolved
+			// (VS Code tears the old one down late). Without this guard that
+			// stale event would null out the live view and drop its state.
+			if (this._view !== webviewView) {
+				return;
+			}
+			this._view = undefined;
+			this._isWebviewReady = false;
+			// A queued prompt is deliberately kept: a disposal is usually a
+			// re-reveal in progress, and the next resolve is what delivers it.
+			// The timeout is what bounds the wait if no view comes back.
+		});
 
 		webviewView.webview.options = {
 			enableScripts: true,
@@ -273,6 +354,7 @@ export class ChatWebviewProvider implements vscode.WebviewViewProvider {
 				this._outputChannel.appendLine(`[Extension] Session initialized automatically: ${sessionId}`);
 				// Broadcast session list to populate History tab
 				await this._broadcastSessions();
+				this._flushPendingPrompt();
 			}
 		} catch (error) {
 			this._outputChannel.appendLine(`Failed to initialize session on ready: ${error}`);
@@ -423,6 +505,10 @@ export class ChatWebviewProvider implements vscode.WebviewViewProvider {
 		try {
 			if (this._acpClient.hasPendingPermissions()) {
 				vscode.window.showWarningMessage('Nanocoder: Please approve or deny the pending tool before sending a new message.');
+				// The webview has already drawn the user bubble and flipped to
+				// the loading state, and no turn is going to start - so end the
+				// turn here or the composer spins until the user hits Escape.
+				this.postMessage({type: 'acpUpdate', update: {sessionUpdate: 'prompt_response'}});
 				return;
 			}