Add Git Worktree Explorer canvas

.github/plugin/marketplace.json

@@ -798,6 +798,12 @@
         "repo": "Azure/git-ape"
       }
     },
+    {
+      "name": "git-worktree-explorer",
+      "source": "plugins/git-worktree-explorer",
+      "description": "Visualize the active Git repository through worktrees, branches, commits, and optional GitHub pull request context.",
+      "version": "1.0.0"
+    },
     {
       "name": "github-copilot-modernization",
       "description": "Autonomous application modernization using multi-agent orchestration for GitHub Copilot CLI. Supports Java upgrades (8→21, Spring Boot 2.x→3.x), .NET modernization, Azure migration, CVE/vulnerability fixing, and application rearchitecture (monolith-to-microservices). Features a 3-level agent hierarchy (orchestrator → coordinators → executors) with enterprise rulebook support for embedding organizational policies into the workflow.",

docs/README.plugins.md

@@ -66,6 +66,7 @@ See [CONTRIBUTING.md](../CONTRIBUTING.md#adding-plugins) for guidelines on how t
 | [frontend-web-dev](../plugins/frontend-web-dev/README.md) | Essential prompts, instructions, and chat modes for modern frontend web development including React, Angular, Vue, TypeScript, and CSS frameworks. | 4 items | frontend, web, react, typescript, javascript, css, html, angular, vue |
 | [gem-team](../plugins/gem-team/README.md) | Self-Learning Multi-agent orchestration framework for spec-driven development and automated verification. With smarter tool calling and leaner context. | 15 items | multi-agent, orchestration, tdd, testing, e2e, devops, security-audit, code-review, prd, mobile |
 | [gesture-review](../plugins/gesture-review/README.md) | Review pull requests with a live camera feed and approve or reject using thumbs-up/thumbs-down gestures. | 1 items | camera-input, gesture-control, github-prs, hands-free, mediapipe, pull-request-review |
+| [git-worktree-explorer](../plugins/git-worktree-explorer/README.md) | Visualize the active Git repository through worktrees, branches, commits, and optional GitHub pull request context. | 1 items | branch-visualization, canvas, commit-history, git, repository-topology, worktrees |
 | [go-mcp-development](../plugins/go-mcp-development/README.md) | Complete toolkit for building Model Context Protocol (MCP) servers in Go using the official github.com/modelcontextprotocol/go-sdk. Includes instructions for best practices, a prompt for generating servers, and an expert chat mode for guidance. | 2 items | go, golang, mcp, model-context-protocol, server-development, sdk |
 | [java-development](../plugins/java-development/README.md) | Comprehensive collection of prompts and instructions for Java development including Spring Boot, Quarkus, testing, documentation, and best practices. | 4 items | java, springboot, quarkus, jpa, junit, javadoc |
 | [java-mcp-development](../plugins/java-mcp-development/README.md) | Complete toolkit for building Model Context Protocol servers in Java using the official MCP Java SDK with reactive streams and Spring Boot integration. | 2 items | java, mcp, model-context-protocol, server-development, sdk, reactive-streams, spring-boot, reactor |

extensions/git-worktree-explorer/copilot-extension.json

@@ -0,0 +1,4 @@
+{
+    "name": "git-worktree-explorer",
+    "version": 1
+}

extensions/git-worktree-explorer/extension.mjs

@@ -0,0 +1,94 @@
+import { CanvasError, createCanvas, joinSession } from "@github/copilot-sdk/extension";
+import { getServerEntry, refreshServer, startServer, stopServer } from "./server.mjs";
+
+const session = await joinSession({
+    canvases: [
+        createCanvas({
+            id: "git-worktree-explorer",
+            displayName: "Git Worktree Explorer",
+            description: "Explore the active Git repository through worktrees, branches, commits, and related GitHub pull requests.",
+            inputSchema: {
+                type: "object",
+                additionalProperties: false,
+                properties: {
+                    startAt: {
+                        type: "string",
+                        enum: ["repository"],
+                        description: "Initial topology level.",
+                    },
+                },
+            },
+            actions: [
+                {
+                    name: "refresh",
+                    description: "Refresh Git and GitHub information shown by an open explorer.",
+                    inputSchema: {
+                        type: "object",
+                        additionalProperties: false,
+                        properties: {},
+                    },
+                    handler: async (ctx) => {
+                        try {
+                            const snapshot = await refreshServer(ctx.instanceId);
+                            return {
+                                gatheredAt: snapshot.gatheredAt,
+                                worktrees: snapshot.worktrees.length,
+                                branches: snapshot.branches.length,
+                            };
+                        } catch (error) {
+                            throw new CanvasError("git_refresh_failed", error.message);
+                        }
+                    },
+                },
+                {
+                    name: "focus_node",
+                    description: "Ask an open explorer to focus a repository, worktree, or branch node by its canvas node ID.",
+                    inputSchema: {
+                        type: "object",
+                        additionalProperties: false,
+                        properties: {
+                            nodeId: { type: "string", minLength: 1 },
+                        },
+                        required: ["nodeId"],
+                    },
+                    handler: async (ctx) => {
+                        const entry = getServerEntry(ctx.instanceId);
+                        if (!entry) throw new CanvasError("canvas_not_open", "Canvas instance is not open.");
+                        const nodeId = ctx.input?.nodeId;
+                        const snapshot = entry.snapshot;
+                        const exists = nodeId === "repository"
+                            || snapshot.worktrees.some((item) => item.id === nodeId)
+                            || snapshot.branches.some((item) => item.id === nodeId);
+                        if (!exists) throw new CanvasError("git_node_not_found", `Git node not found: ${nodeId}`);
+                        for (const client of entry.clients) {
+                            client.write(`event: focus\ndata: ${JSON.stringify({ nodeId })}\n\n`);
+                        }
+                        return { nodeId };
+                    },
+                },
+            ],
+            open: async (ctx) => {
+                const cwd = ctx.session?.workingDirectory;
+                if (!cwd) {
+                    throw new CanvasError("workspace_unavailable", "The active session working directory is unavailable.");
+                }
+                try {
+                    const entry = await startServer(ctx.instanceId, {
+                        cwd,
+                        sendPrompt: async (prompt) => session.send({ prompt }),
+                    });
+                    return {
+                        title: "Git Worktree Explorer",
+                        status: `${entry.snapshot.worktrees.length} worktrees · ${entry.snapshot.branches.length} branches`,
+                        url: entry.url,
+                    };
+                } catch (error) {
+                    throw new CanvasError("git_repository_unavailable", error.message);
+                }
+            },
+            onClose: async (ctx) => {
+                await stopServer(ctx.instanceId);
+            },
+        }),
+    ],
+});