--- plugins/provider-acp/src/bridge/fake-acp-agent.mjs
+++ fake-opencode-acp-agent.mjs
@@ -302,6 +302,89 @@
       outcome = "error";
     }
     notifyUpdate(messageChunk(`permission:${outcome}`));
+  } else if (text.includes("opencode-write")) {
+    // Mirrors what opencode's ACP layer sends when its `write` tool needs
+    // permission (anomalyco/opencode packages/opencode/src/acp/permission.ts
+    // + acp/tool.ts). The tool_call itself is always kind "edit"; the
+    // permission request's toolCall depends on which permission fires:
+    //   FAKE_ACP_PERMISSION=write (default): the write/edit permission ->
+    //     kind "edit", title = file path, locations = [{ path: file }],
+    //     rawInput = { filePath, content }, NO command.
+    //   FAKE_ACP_PERMISSION=external_directory: the external_directory
+    //     permission (write outside the project) -> toToolKind has no case
+    //     for it so kind "other", title = parentDir (a bare directory),
+    //     locations = [{ path: file }, { path: parentDir }],
+    //     rawInput = { filepath, parentDir }, NO command.
+    const filePath = process.env.FAKE_ACP_WRITE_PATH ?? "/tmp/qa-1719/notes.md";
+    const parentDir = filePath.slice(0, filePath.lastIndexOf("/")) || "/";
+    const external = process.env.FAKE_ACP_PERMISSION === "external_directory";
+    const permissionToolCall = external
+      ? {
+          toolCallId: "write-tool-1",
+          title: parentDir,
+          kind: "other",
+          status: "pending",
+          locations: [{ path: filePath }, { path: parentDir }],
+          rawInput: { filepath: filePath, parentDir },
+        }
+      : {
+          toolCallId: "write-tool-1",
+          title: filePath,
+          kind: "edit",
+          status: "pending",
+          locations: [{ path: filePath }],
+          rawInput: { filePath, content: "hello from agent\n" },
+        };
+    notifyUpdate({
+      sessionUpdate: "tool_call",
+      toolCallId: "write-tool-1",
+      title: filePath,
+      kind: "edit",
+      status: "pending",
+      locations: [{ path: filePath }],
+      rawInput: { filePath, content: "hello from agent\n" },
+    });
+    let outcome = "cancelled";
+    try {
+      const result = await requestClient("session/request_permission", {
+        sessionId: activeSessionId,
+        toolCall: permissionToolCall,
+        options: [
+          { optionId: "once", name: "Allow once", kind: "allow_once" },
+          { optionId: "always", name: "Always allow", kind: "allow_always" },
+          { optionId: "reject", name: "Reject", kind: "reject_once" },
+        ],
+      });
+      outcome =
+        result?.outcome?.outcome === "selected"
+          ? result.outcome.optionId
+          : "cancelled";
+    } catch {
+      outcome = "error";
+    }
+    if (outcome === "once" || outcome === "always") {
+      notifyUpdate({
+        sessionUpdate: "tool_call_update",
+        toolCallId: "write-tool-1",
+        title: filePath,
+        kind: "edit",
+        status: "completed",
+        locations: [{ path: filePath }],
+        content: [
+          { type: "diff", path: filePath, oldText: null, newText: "hello from agent\n" },
+        ],
+        rawInput: { filePath, content: "hello from agent\n" },
+      });
+    } else {
+      notifyUpdate({
+        sessionUpdate: "tool_call_update",
+        toolCallId: "write-tool-1",
+        title: filePath,
+        kind: "edit",
+        status: "failed",
+      });
+    }
+    notifyUpdate(messageChunk(`permission:${outcome}`));
   } else if (text.includes("write-file")) {
     try {
       await requestClient("fs/write_text_file", {