feat(grok): give the Grok Intake its propose_draft tool (draft card)

The prompter prompt tells the model to call propose_draft when the spec is
ready, but on Grok that tool didn't exist — so no draft chunk, no panel draft
card, and the human couldn't launch a task from a Grok intake chat.

- intake-tools.js: opencode plugin registering propose_draft via Hooks.tool;
  the execute() only ACKs — the driver (OpencodeServeSession.normalize ->
  _is_propose_draft -> _draft_from_tool_input) intercepts the tool CALL and
  emits the `draft` chunk the panel renders.
- agent-grok-prompter.Dockerfile: bake the plugin, scoped to this image via
  ROBOCO_OPENCODE_EXTRA_PLUGINS (delivery roles never draft).
- test: a propose_draft tool part normalizes to a draft chunk (not a tool_use).

The live tool-call -> draft-card path is flagged UNVERIFIED-LIVE for the NAS.

docker/agent-grok-prompter.Dockerfile

@@ -10,6 +10,14 @@
 
 FROM roboco-agent-grok
 
+USER root
+
+# The intake propose_draft tool plugin (the model calls it; the driver turns the
+# call into the panel's draft card). Scoped to THIS image via
+# ROBOCO_OPENCODE_EXTRA_PLUGINS so only the intake role carries it.
+COPY docker/grok/intake-tools.js /app/opencode-plugins/intake-tools.js
+ENV ROBOCO_OPENCODE_EXTRA_PLUGINS=/app/opencode-plugins/intake-tools.js
+
 USER agent
 
 LABEL role="grok-prompter"

docker/grok/intake-tools.js

@@ -0,0 +1,44 @@
+// opencode plugin — the Intake interviewer's propose_draft tool, on Grok.
+//
+// Parity with the Claude Intake's SDK tool (roboco.agent_sdk.intake_driver
+// .build_intake_options): the model calls propose_draft once the task spec is
+// ready, and the driver (OpencodeServeSession.normalize_opencode_message ->
+// _is_propose_draft -> _draft_from_tool_input) turns that tool call into the
+// `draft` chunk the panel renders as the reviewable draft card.
+//
+// Without this, propose_draft is a tool the prompter prompt tells the model to
+// call but that does not exist on Grok, so no draft card ever appears and the
+// human can't launch a task from a Grok intake chat. The execute() only ACKs —
+// the payload that matters is the tool-CALL input, which the driver intercepts.
+//
+// Loaded ONLY into the roboco-agent-grok-prompter image via
+// ROBOCO_OPENCODE_EXTRA_PLUGINS (the one-shot delivery roles never draft).
+//
+// UNVERIFIED-LIVE: opencode's exact tool-call Part shape in the synchronous
+// serve reply — confirm a Grok intake spec yields a draft chunk -> panel card
+// on the NAS before relying on Grok intake.
+
+import { tool } from "@opencode-ai/plugin";
+
+export default async () => ({
+  tool: {
+    propose_draft: tool({
+      description:
+        "Submit the finished task draft for the human to review and confirm. " +
+        "Call this once the spec is complete. Pass a JSON object: title, " +
+        "objective, what_this_builds[], the_work[] ({team, summary, items}), " +
+        "notes[], acceptance_criteria[], team, scale, task_type, nature, " +
+        "estimated_complexity, priority.",
+      args: {
+        draft: tool.schema
+          .record(tool.schema.string(), tool.schema.any())
+          .describe("The task draft object"),
+      },
+      async execute() {
+        // The driver intercepts the tool CALL and emits the draft chunk; this
+        // handler only acknowledges so the model knows the draft landed.
+        return "Draft submitted — the human can review it.";
+      },
+    }),
+  },
+});

tests/unit/agent_sdk/test_opencode_session.py

@@ -51,6 +51,27 @@ def test_fenced_draft_in_text_becomes_draft_chunk() -> None:
     assert draft.data["title"] == "Add login"
 
 
+def test_propose_draft_tool_part_becomes_draft_chunk() -> None:
+    # The intake-tools.js propose_draft tool call (its input nested under
+    # `draft`) is intercepted into a draft chunk — NOT rendered as a tool_use —
+    # so the panel shows the draft card. This is the primary Grok-intake path.
+    chunks = normalize_opencode_message(
+        {
+            "parts": [
+                {
+                    "type": "tool",
+                    "tool": "propose_draft",
+                    "input": {"draft": {"title": "Add login", "team": "backend"}},
+                }
+            ]
+        }
+    )
+    assert "tool_use" not in _kinds(chunks)
+    draft = next(c for c in chunks if c.kind == "draft")
+    assert draft.data["title"] == "Add login"
+    assert draft.data["team"] == "backend"
+
+
 def test_unknown_part_skipped_but_turn_still_ends() -> None:
     chunks = normalize_opencode_message({"parts": [{"type": "mystery", "x": 1}]})
     assert _kinds(chunks) == ["turn_end"]