Add Opencode plugin

Add OpenCode plugin

Author: benvinegar

README.md

@@ -9,6 +9,7 @@ Paste a screenshot in your browser, your agent gets the URL instantly.
 | Agent | Directory | Status |
 |---|---|---|
 | [pi](https://github.com/mariozechner/pi) | [`pi/`](pi/) | ✅ |
+| [OpenCode](https://github.com/anomalyco/opencode) | [`opencode/`](opencode/) | ✅ |
 
 ## How it works
 

opencode/README.md

@@ -0,0 +1,55 @@
+# glance.sh plugin for OpenCode
+
+[OpenCode](https://github.com/anomalyco/opencode) plugin that lets your agent request screenshots from you via [glance.sh](https://glance.sh).
+
+## What it does
+
+Maintains a **persistent background session** on glance.sh. Paste an image anytime — the agent receives it instantly.
+
+- **Background listener** — starts when OpenCode launches, reconnects automatically, refreshes sessions before they expire.
+- **`glance` tool** — the LLM calls it when it needs to see something visual. Surfaces the session URL and waits for the next paste.
+- **Multiple images** — paste as many images as you want during a session.
+
+## Install
+
+Symlink or copy `glance.ts` into your OpenCode plugins directory:
+
+```bash
+# symlink (recommended — stays up to date with git pulls)
+ln -s "$(pwd)/glance.ts" ~/.config/opencode/plugins/glance.ts
+
+# or per-project
+ln -s "$(pwd)/glance.ts" .opencode/plugins/glance.ts
+```
+
+Restart OpenCode. The background session starts automatically.
+
+## How it works
+
+```
+opencode starts
+  └─▶ plugin creates session on glance.sh
+  └─▶ connects SSE (background, auto-reconnect)
+
+LLM calls glance tool
+  └─▶ surfaces session URL
+  └─▶ waits for image paste
+
+user pastes image at /s/<id>
+  └─▶ SSE emits "image" event
+  └─▶ tool returns image URL to LLM
+
+session expires (~10 min)
+  └─▶ plugin creates new session, reconnects
+```
+
+## Requirements
+
+- [OpenCode](https://github.com/anomalyco/opencode) v0.1+
+- Bun runtime (ships with OpenCode)
+
+## Configuration
+
+No API keys required — sessions are anonymous and ephemeral (10-minute TTL).
+
+The plugin connects to `https://glance.sh` by default. The SSE connection is held for ~5 minutes per cycle, with automatic reconnection.

opencode/glance.test.ts

@@ -0,0 +1,217 @@
+import { describe, it, expect, vi, afterEach } from "vitest"
+
+// Mock @opencode-ai/plugin — `tool()` is a passthrough that returns the config
+vi.mock("@opencode-ai/plugin", () => ({
+  tool: (config: any) => config,
+}))
+
+// Helper: dynamically import the plugin to get fresh module-level state
+async function loadPlugin() {
+  vi.resetModules()
+  vi.doMock("@opencode-ai/plugin", () => ({
+    tool: (config: any) => config,
+  }))
+  const mod = await import("./glance.js")
+  return mod.GlancePlugin
+}
+
+function mockClient() {
+  return { client: {} }
+}
+
+function mockContext(abort?: AbortSignal) {
+  return {
+    metadata: vi.fn(),
+    abort,
+  }
+}
+
+/**
+ * Build a ReadableStream that emits the given SSE chunks, then hangs forever.
+ * The hang prevents the background loop from spinning in a tight reconnect cycle.
+ */
+function sseStream(events: string[]) {
+  const encoder = new TextEncoder()
+  let i = 0
+  return new ReadableStream({
+    pull(controller) {
+      if (i < events.length) {
+        controller.enqueue(encoder.encode(events[i]))
+        i++
+        return
+      }
+      // Hang forever after all events are emitted
+      return new Promise(() => {})
+    },
+  })
+}
+
+function cleanupWaiters() {
+  for (const key of Object.keys(globalThis)) {
+    if (key.startsWith("__glance_waiter_")) {
+      delete (globalThis as any)[key]
+    }
+  }
+}
+
+/**
+ * URL-aware fetch mock. Routes by URL so both the background loop and
+ * tool calls get correct responses regardless of call order.
+ */
+function routedFetch(opts: {
+  session?: { id: string; url: string }
+  sessionError?: number
+  sseEvents?: string[]
+}) {
+  return vi.fn(async (url: string, _init?: any) => {
+    if (url === "https://glance.sh/api/session") {
+      if (opts.sessionError) {
+        return { ok: false, status: opts.sessionError }
+      }
+      return {
+        ok: true,
+        json: async () => opts.session ?? { id: "test-id", url: "/s/test-id" },
+      }
+    }
+
+    if (typeof url === "string" && url.includes("/events")) {
+      return {
+        ok: true,
+        body: sseStream(opts.sseEvents ?? []),
+      }
+    }
+
+    return { ok: false, status: 404 }
+  })
+}
+
+describe("opencode glance plugin", () => {
+  afterEach(() => {
+    vi.restoreAllMocks()
+    cleanupWaiters()
+  })
+
+  describe("glance tool", () => {
+    it("creates a session and returns the URL", async () => {
+      vi.stubGlobal(
+        "fetch",
+        routedFetch({ session: { id: "abc123", url: "/s/abc123" } }),
+      )
+
+      const GlancePlugin = await loadPlugin()
+      const plugin = await GlancePlugin(mockClient())
+      const result = await plugin.tool.glance.execute({})
+
+      expect(result).toContain("https://glance.sh/s/abc123")
+      expect(result).toContain("Session ready")
+    })
+
+    it("reuses an existing session on second call", async () => {
+      const fetchFn = routedFetch({
+        session: { id: "abc123", url: "/s/abc123" },
+      })
+      vi.stubGlobal("fetch", fetchFn)
+
+      const GlancePlugin = await loadPlugin()
+      const plugin = await GlancePlugin(mockClient())
+
+      // Let background loop create its session
+      await new Promise((r) => setTimeout(r, 20))
+
+      const r1 = await plugin.tool.glance.execute({})
+      const r2 = await plugin.tool.glance.execute({})
+
+      expect(r1).toContain("/s/abc123")
+      expect(r2).toContain("/s/abc123")
+    })
+
+    it("returns error when session creation fails", async () => {
+      vi.stubGlobal("fetch", routedFetch({ sessionError: 500 }))
+
+      const GlancePlugin = await loadPlugin()
+      const plugin = await GlancePlugin(mockClient())
+
+      // Wait for background loop to fail
+      await new Promise((r) => setTimeout(r, 50))
+
+      const result = await plugin.tool.glance.execute({})
+      expect(result).toContain("Failed to create session")
+    })
+  })
+
+  describe("glance_wait tool", () => {
+    it("returns error when no session exists", async () => {
+      vi.stubGlobal(
+        "fetch",
+        vi.fn().mockRejectedValue(new Error("no network")),
+      )
+
+      const GlancePlugin = await loadPlugin()
+      const plugin = await GlancePlugin(mockClient())
+
+      // Give background loop time to fail
+      await new Promise((r) => setTimeout(r, 50))
+
+      const ctx = mockContext()
+      const result = await plugin.tool.glance_wait.execute({}, ctx)
+      expect(result).toContain("No active session")
+    })
+
+    it("returns image URL when image is dispatched", async () => {
+      const imagePayload = JSON.stringify({
+        url: "https://glance.sh/tok123.png",
+        expiresAt: Date.now() + 60_000,
+      })
+
+      vi.stubGlobal(
+        "fetch",
+        routedFetch({
+          session: { id: "sess1", url: "/s/sess1" },
+          sseEvents: [
+            `event: connected\ndata: {}\n\n`,
+            `event: image\ndata: ${imagePayload}\n\n`,
+          ],
+        }),
+      )
+
+      const GlancePlugin = await loadPlugin()
+      const plugin = await GlancePlugin(mockClient())
+
+      // Ensure session exists
+      await plugin.tool.glance.execute({})
+
+      const ctx = mockContext()
+      const result = await plugin.tool.glance_wait.execute({}, ctx)
+
+      expect(result).toContain("https://glance.sh/tok123.png")
+      expect(ctx.metadata).toHaveBeenCalledWith(
+        expect.objectContaining({
+          title: expect.stringContaining("Waiting for paste"),
+        }),
+      )
+    })
+
+    it("returns timeout message when aborted", async () => {
+      vi.stubGlobal(
+        "fetch",
+        routedFetch({
+          session: { id: "sess2", url: "/s/sess2" },
+        }),
+      )
+
+      const GlancePlugin = await loadPlugin()
+      const plugin = await GlancePlugin(mockClient())
+      await plugin.tool.glance.execute({})
+
+      const ac = new AbortController()
+      const ctx = mockContext(ac.signal)
+
+      const waitPromise = plugin.tool.glance_wait.execute({}, ctx)
+      await new Promise((r) => setTimeout(r, 50))
+      ac.abort()
+
+      const result = await waitPromise
+      expect(result).toContain("timed out")
+    })
+  })
+})