Assistant: Initial experimental git integration

extensions/positron-assistant/package.json

@@ -104,6 +104,20 @@
         ]
       }
     ],
+    "menus": {
+      "scm/inputBox": [
+        {
+          "command": "positron-assistant.generateCommitMessage",
+          "group": "navigation",
+          "when": "!positron-assistant.generatingCommitMessage && config.positron.assistant.gitIntegration.enable"
+        },
+        {
+          "command": "positron-assistant.cancelGenerateCommitMessage",
+          "group": "navigation",
+          "when": "positron-assistant.generatingCommitMessage && config.positron.assistant.gitIntegration.enable"
+        }
+      ]
+    },
     "commands": [
       {
         "command": "positron-assistant.configureModels",
@@ -116,6 +130,20 @@
         "title": "%commands.logStoredModels.title%",
         "category": "%commands.category%",
         "enablement": "config.positron.assistant.enable"
+      },
+      {
+        "command": "positron-assistant.generateCommitMessage",
+        "title": "%commands.generateCommitMessage.title%",
+        "category": "%commands.category%",
+        "enablement": "config.positron.assistant.enable && config.positron.assistant.gitIntegration.enable",
+        "icon": "$(sparkle)"
+      },
+      {
+        "command": "positron-assistant.cancelGenerateCommitMessage",
+        "title": "%commands.cancelGenerateCommitMessage.title%",
+        "category": "%commands.category%",
+        "enablement": "config.positron.assistant.enable && config.positron.assistant.gitIntegration.enable",
+        "icon": "$(stop)"
       }
     ],
     "configuration": [
@@ -146,6 +174,12 @@
             "items": {
               "type": "string"
             }
+          },
+          "positron.assistant.gitIntegration.enable": {
+            "type": "boolean",
+            "default": false,
+            "description": "%configuration.gitIntegration.description%",
+            "tags": ["experimental"]
           }
         }
       }
@@ -360,6 +394,23 @@
             }
           }
         }
+      },
+      {
+        "name": "getChangedFiles",
+        "displayName": "Get changed files",
+        "modelDescription": "Get summaries and git diffs for current changes to files in this workspace.",
+        "canBeReferencedInPrompt": true,
+        "userDescription": "Get changed files",
+        "toolReferenceName": "changes",
+        "when": "config.positron.assistant.gitIntegration.enable",
+        "icon": "$(diff)",
+        "tags": [
+          "positron-assistant"
+        ],
+        "inputSchema": {
+          "type": "object",
+          "properties": {}
+        }
       }
     ]
   },

extensions/positron-assistant/package.nls.json

@@ -3,6 +3,8 @@
 	"description": "Provides default assistant and language models for Positron.",
 	"commands.configureModels.title": "Configure Language Model Providers",
 	"commands.logStoredModels.title": "Log the stored language models",
+	"commands.generateCommitMessage.title": "Generate Commit Message",
+	"commands.cancelGenerateCommitMessage.title": "Cancel Generate Commit Message",
 	"commands.copilot.signin.title": "Copilot Sign In",
 	"commands.copilot.signout.title": "Copilot Sign Out",
 	"commands.category": "Positron Assistant",
@@ -15,5 +17,6 @@
 	"configuration.enable.markdownDescription": "Enable [Positron Assistant](https://positron.posit.co/assistant), an AI assistant for Positron.",
 	"configuration.useAnthropicSdk.description": "Use the Anthropic SDK for Anthropic models rather than the generic AI SDK.",
 	"configuration.streamingEdits.enable": "Enable streaming edits in inline editor chats.",
-	"configuration.inlineCompletionExcludes.description": "A list of [glob patterns](https://aka.ms/vscode-glob-patterns) to exclude from inline completions."
+	"configuration.inlineCompletionExcludes.description": "A list of [glob patterns](https://aka.ms/vscode-glob-patterns) to exclude from inline completions.",
+	"configuration.gitIntegration.description": "Enable Positron Assistant git integration."
 }

extensions/positron-assistant/src/extension.ts

@@ -14,6 +14,7 @@ import { registerAssistantTools } from './tools.js';
 import { registerCopilotService } from './copilot.js';
 import { ALL_DOCUMENTS_SELECTOR, DEFAULT_MAX_TOKEN_OUTPUT } from './constants.js';
 import { registerCodeActionProvider } from './codeActions.js';
+import { generateCommitMessage } from './git.js';
 
 const hasChatModelsContextKey = 'positron-assistant.hasChatModels';
 
@@ -208,6 +209,14 @@ function registerConfigureModelsCommand(context: vscode.ExtensionContext, storag
 	);
 }
 
+function registerGenerateCommitMessageCommand(context: vscode.ExtensionContext) {
+	context.subscriptions.push(
+		vscode.commands.registerCommand('positron-assistant.generateCommitMessage', () => {
+			generateCommitMessage(context);
+		})
+	);
+}
+
 function registerAssistant(context: vscode.ExtensionContext) {
 
 	// Initialize secret storage. In web mode, we currently need to use global
@@ -230,6 +239,7 @@ function registerAssistant(context: vscode.ExtensionContext) {
 
 	// Commands
 	registerConfigureModelsCommand(context, storage);
+	registerGenerateCommitMessageCommand(context);
 
 	// Register mapped edits provider
 	registerMappedEditsProvider(context, participantService, log);

extensions/positron-assistant/src/git.ts

@@ -0,0 +1,163 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (C) 2025 Posit Software, PBC. All rights reserved.
+ *  Licensed under the Elastic License 2.0. See LICENSE.txt for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import * as vscode from 'vscode';
+import * as fs from 'fs';
+
+import { GitExtension, Repository, Status, Change } from '../../git/src/api/git.js';
+import { EXTENSION_ROOT_DIR } from './constants';
+
+const mdDir = `${EXTENSION_ROOT_DIR}/src/md/`;
+const generatingGitCommitKey = 'positron-assistant.generatingCommitMessage';
+
+export enum GitRepoChangeKind {
+	Staged = 'staged',
+	Unstaged = 'unstaged',
+	Merge = 'merge',
+	Untracked = 'untracked',
+	All = 'all',
+}
+
+export interface GitRepoChangeSummary {
+	uri: vscode.Uri;
+	summary: string;
+}
+
+export interface GitRepoChange {
+	repo: Repository;
+	changes: GitRepoChangeSummary[];
+}
+
+/** Get the list of active repositories */
+function currentGitRepositories(): Repository[] {
+	// Obtain a handle to git extension API
+	const gitExtension = vscode.extensions.getExtension<GitExtension>('vscode.git')?.exports;
+	if (!gitExtension) {
+		throw new Error('Git extension not found');
+	}
+	const git = gitExtension.getAPI(1);
+	if (git.repositories.length === 0) {
+		throw new Error('No Git repositories found');
+	}
+
+	return git.repositories;
+}
+
+/** Summarise the content of a git change */
+async function gitChangeSummary(repo: Repository, change: Change, kind: GitRepoChangeKind): Promise<GitRepoChangeSummary> {
+	const uri = change.uri.fsPath.replace(repo.rootUri.fsPath, '');
+	const originalUri = change.originalUri.fsPath.replace(repo.rootUri.fsPath, '');
+	const renameUri = change.renameUri?.fsPath.replace(repo.rootUri.fsPath, '');
+	switch (change.status) {
+		// File-level changes
+		case Status.INDEX_ADDED:
+		case Status.UNTRACKED:
+			return { uri: change.uri, summary: `Added: ${uri}` };
+		case Status.INDEX_DELETED:
+		case Status.DELETED:
+			return { uri: change.uri, summary: `Deleted: ${uri}` };
+		case Status.INDEX_RENAMED:
+			return { uri: change.uri, summary: `Renamed: ${originalUri} to ${renameUri}` };
+		case Status.INDEX_COPIED:
+			return { uri: change.uri, summary: `Copied: ${originalUri} to ${uri}` };
+		case Status.IGNORED:
+			return { uri: change.uri, summary: `Ignored: ${uri}` };
+		default: {
+			// Otherwise, git diff text content for this file
+			if (kind === GitRepoChangeKind.Staged) {
+				const diff = await repo.diffIndexWithHEAD(change.uri.fsPath);
+				return { uri: change.uri, summary: `Modified:\n${diff}` };
+			} else {
+				const diff = await repo.diffWithHEAD(change.uri.fsPath);
+				return { uri: change.uri, summary: `Modified:\n${diff}` };
+			}
+		}
+	}
+}
+
+/** Get current workspace git repository changes as text summaries */
+export async function getWorkspaceGitChanges(kind: GitRepoChangeKind): Promise<GitRepoChange[]> {
+	const repos = currentGitRepositories();
+
+	// Combine and summarise each kind of git repo change
+	const repoChanges = await Promise.all(repos.map(async (repo) => {
+		const stateChanges: { change: Change; kind: GitRepoChangeKind }[] = [];
+
+		if (kind === GitRepoChangeKind.Staged || kind === GitRepoChangeKind.All) {
+			stateChanges.push(...repo.state.indexChanges.map((change) => {
+				return { change, kind: GitRepoChangeKind.Staged };
+			}));
+		}
+		if (kind === GitRepoChangeKind.Unstaged || kind === GitRepoChangeKind.All) {
+			stateChanges.push(...repo.state.workingTreeChanges.map((change) => {
+				return { change, kind: GitRepoChangeKind.Unstaged };
+			}));
+		}
+		if (kind === GitRepoChangeKind.Untracked || kind === GitRepoChangeKind.All) {
+			stateChanges.push(...repo.state.untrackedChanges.map((change) => {
+				return { change, kind: GitRepoChangeKind.Untracked };
+			}));
+		}
+		if (kind === GitRepoChangeKind.Merge || kind === GitRepoChangeKind.All) {
+			stateChanges.push(...repo.state.mergeChanges.map((change) => {
+				return { change, kind: GitRepoChangeKind.Merge };
+			}));
+		}
+
+		const changes = await Promise.all(stateChanges.map(async (state) => {
+			return gitChangeSummary(repo, state.change, state.kind);
+		}));
+		return { repo, changes };
+	}));
+
+	return repoChanges.filter((repoChange) => repoChange.changes.length > 0);
+}
+
+/** Generate a commit message for git repositories with staged changes */
+export async function generateCommitMessage(context: vscode.ExtensionContext) {
+	await vscode.commands.executeCommand('setContext', generatingGitCommitKey, true);
+
+	const models = (await vscode.lm.selectChatModels()).filter((model) => {
+		return model.family !== 'echo' && model.family !== 'error';
+	});
+	if (models.length === 0) {
+		vscode.commands.executeCommand('setContext', generatingGitCommitKey, false);
+		throw new Error('No language models available for commit message generation.');
+	}
+	const model = models[0];
+
+	const tokenSource: vscode.CancellationTokenSource = new vscode.CancellationTokenSource();
+	const cancelDisposable = vscode.commands.registerCommand('positron-assistant.cancelGenerateCommitMessage', () => {
+		tokenSource.cancel();
+		vscode.commands.executeCommand('setContext', generatingGitCommitKey, false);
+	});
+
+	// Send repo changes to the LLM and update the commit message input boxes
+	const allChanges = await getWorkspaceGitChanges(GitRepoChangeKind.All);
+	const stagedChanges = await getWorkspaceGitChanges(GitRepoChangeKind.Staged);
+	const gitChanges = stagedChanges.length > 0 ? stagedChanges : allChanges;
+
+	const system: string = await fs.promises.readFile(`${mdDir}/prompts/git/commit.md`, 'utf8');
+	try {
+		await Promise.all(gitChanges.map(async ({ repo, changes }) => {
+			if (changes.length > 0) {
+				const response = await model.sendRequest([
+					vscode.LanguageModelChatMessage.User(changes.map(change => change.summary).join('\n')),
+				], { modelOptions: { system } }, tokenSource.token);
+
+				repo.inputBox.value = '';
+				for await (const delta of response.text) {
+					if (tokenSource.token.isCancellationRequested) {
+						return null;
+					}
+					repo.inputBox.value += delta;
+				}
+			}
+		}));
+	} finally {
+		cancelDisposable.dispose();
+		vscode.commands.executeCommand('setContext', generatingGitCommitKey, false);
+	}
+}

extensions/positron-assistant/src/md/prompts/git/commit.md

@@ -0,0 +1,3 @@
+You will be given a set of repository changes and diffs. Output a short git commit message summarizing the changes.
+
+Return ONLY the commit message.

extensions/positron-assistant/src/participants.ts

@@ -313,6 +313,16 @@ abstract class PositronAssistantParticipant implements IPositronAssistantPartici
 			}
 		}
 
+		// If the user has explicitly attached a tool reference, add it to the prompt.
+		if (request.toolReferences.length > 0) {
+			const referencePrompts: string[] = [];
+			for (const reference of request.toolReferences) {
+				referencePrompts.push(xml.node('tool', reference.name));
+			}
+			const toolReferencesText = 'Attached tool references:';
+			prompts.push(xml.node('tool-references', `${toolReferencesText}\n${referencePrompts.join('\n')}`));
+		}
+
 		// If the user has explicitly attached files as context, add them to the prompt.
 		if (request.references.length > 0) {
 			const attachmentPrompts: string[] = [];
@@ -523,8 +533,12 @@ abstract class PositronAssistantParticipant implements IPositronAssistantPartici
 			this._participantService.trackSessionModel(toolContext.sessionId, request.model.id);
 		}
 
+		// If a user attached a tool reference, ensure it is invoked
+		const toolMode = request.toolReferences.length > 0 ? vscode.LanguageModelChatToolMode.Required : vscode.LanguageModelChatToolMode.Auto;
+
 		const modelResponse = await request.model.sendRequest(messages, {
 			tools,
+			toolMode,
 			modelOptions: {
 				toolInvocationToken: request.toolInvocationToken,
 				system,

extensions/positron-assistant/src/tools.ts

@@ -9,6 +9,7 @@ import { LanguageModelImage } from './languageModelParts.js';
 import { ParticipantService } from './participants.js';
 import { PositronAssistantToolName } from './types.js';
 import { ProjectTreeTool } from './tools/projectTreeTool.js';
+import { getWorkspaceGitChanges, GitRepoChangeKind } from './git.js';
 import { DocumentCreateTool } from './tools/documentCreate.js';
 
 
@@ -281,6 +282,21 @@ export function registerAssistantTools(
 		}
 	});
 
+	const getChangedFilesTool = vscode.lm.registerTool<{}>(PositronAssistantToolName.GetChangedFiles, {
+		invoke: async (options, token) => {
+			const repoChanges = await getWorkspaceGitChanges(GitRepoChangeKind.All);
+			const textChanges = repoChanges.map((({ changes }) => {
+				return changes.map((change) => change.summary).join('\n');
+			})).join('\n\n');
+
+			return new vscode.LanguageModelToolResult([
+				new vscode.LanguageModelTextPart(textChanges)
+			]);
+		},
+	});
+
+	context.subscriptions.push(getChangedFilesTool);
+
 	context.subscriptions.push(inspectVariablesTool);
 
 	context.subscriptions.push(ProjectTreeTool);

extensions/positron-assistant/src/types.ts

@@ -11,6 +11,7 @@ export enum PositronAssistantToolName {
 	InspectVariables = 'inspectVariables',
 	SelectionEdit = 'selectionEdit',
 	ProjectTree = 'getProjectTree',
+	GetChangedFiles = 'getChangedFiles',
 	DocumentCreate = 'documentCreate',
 	TextSearch = 'positron_findTextInProject_internal',
 	FileContents = 'positron_getFileContents_internal',