feat(supervise): non-blocking MCP — pending carries proposal id + check-proposal poll tool

Closes #412.

The supervise MCP server blocked the agent's tool call polling for the
operator's decision, and on timeout returned `status: pending` with no
proposal id and no way to poll a specific proposal — so the only way to
learn a late decision was to re-propose (a duplicate).

- `handle_tools_call` pending timeout now returns the `proposal_id` and
  points the agent at `check-proposal`.
- New `check-proposal` MCP tool: non-blocking status lookup by proposal id
  (pending | approved | modified | rejected | unknown). Reuses the queue's
  FileNotFoundError semantics; archives a decided proposal exactly like the
  synchronous path, so a pending proposal stays visible to the operator
  until it's both decided and polled.
- `TOOL_CHECK_PROPOSAL` constant, re-exported from supervise; kept out of
  TOOLS since it never becomes a Proposal.tool.

Enforcement is unchanged — the tools only propose policy; the egress proxy
and git-gate still enforce — so returning early opens no hole. Follow-ups
(git-gate reject-requeue, backpressure, notifications, web console) are in
the PRD.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YBCHap11yGAKuKfsehNPaD

bot_bottle/supervise.py

@@ -47,6 +47,7 @@ from .supervise_types import (
     STATUS_MODIFIED,
     STATUS_REJECTED,
     TOOLS,
+    TOOL_CHECK_PROPOSAL,
     TOOL_EGRESS_ALLOW,
     TOOL_EGRESS_BLOCK,
     TOOL_EGRESS_TOKEN_ALLOW,
@@ -263,6 +264,7 @@ __all__ = [
     "TOOLS",
     "EGRESS_FORWARD_PROXY",
     "EGRESS_INTROSPECT_URL",
+    "TOOL_CHECK_PROPOSAL",
     "TOOL_EGRESS_ALLOW",
     "TOOL_EGRESS_BLOCK",
     "TOOL_GITLEAKS_ALLOW",

bot_bottle/supervise_server.py

@@ -2,14 +2,24 @@
 
 Per-bottle MCP server exposing tools the agent calls to propose egress
 config changes when stuck. The tools are `egress-allow`,
-`egress-block`, and `list-egress-routes`.
+`egress-block`, `list-egress-routes`, and `check-proposal`.
 
-Each queued tool call:
+Each queued proposal tool call:
 
   1. Validates the proposed file syntactically.
   2. Writes a Proposal to the host SQLite database.
-  3. Blocks polling for a matching Response row.
-  4. Returns the operator's `{status, notes}` to the agent.
+  3. Blocks polling for a matching Response row, up to a short grace
+     window (`SUPERVISE_RESPONSE_TIMEOUT_SECONDS`, default 30s).
+  4. On a decision within the window, returns the operator's
+     `{status, notes}`. On timeout, returns `status: pending` **with the
+     proposal id** and leaves the proposal queued — the flow is
+     non-blocking past the grace window (PRD prd-new / issue #412).
+
+`check-proposal` is the non-blocking companion: given a `proposal_id`
+returned by a `pending` response, it reports the current decision
+(`pending` | `approved` | `modified` | `rejected`) without re-proposing,
+so an approval made out-of-band (e.g. a web review console) can be resumed
+without holding an HTTP request open.
 
 One shared server fronts every bottle (PRD 0070) and attributes each
 proposal to the calling bottle by source IP, resolved from the orchestrator
@@ -22,7 +32,9 @@ Speaks MCP over HTTP+JSON-RPC. Methods handled:
   * `initialize`           — handshake; returns server info + caps.
   * `notifications/initialized` — ack-only.
   * `tools/list`           — returns the tool definitions.
-  * `tools/call`           — validates, queues, blocks, returns.
+  * `tools/call`           — validates, queues, waits out the grace
+                             window, returns (pending past it); or, for
+                             `check-proposal`, a non-blocking status poll.
 
 Everything else returns JSON-RPC error -32601 (method not found).
 
@@ -232,6 +244,31 @@ TOOL_DEFINITIONS: list[dict[str, object]] = [
         ),
         "inputSchema": _proposal_input_schema(),
     },
+    {
+        "name": _sv.TOOL_CHECK_PROPOSAL,
+        "description": (
+            "Poll a previously queued proposal for the operator's decision "
+            "WITHOUT blocking or re-proposing. Pass the `proposal_id` you "
+            "got back when an `egress-allow`/`egress-block` call returned "
+            "`status: pending`. Returns the current status: `pending` (no "
+            "decision yet — poll again later), `approved`, `modified`, "
+            "`rejected`, or `unknown` (no such queued proposal — wrong id, "
+            "or it was already resolved and read)."
+        ),
+        "inputSchema": {
+            "type": "object",
+            "properties": {
+                "proposal_id": {
+                    "type": "string",
+                    "description": (
+                        "The proposal id from a `pending` response."
+                    ),
+                },
+            },
+            "required": ["proposal_id"],
+            "additionalProperties": False,
+        },
+    },
 ]
 
 
@@ -353,7 +390,7 @@ def handle_tools_call(
             deadline=deadline,
         )
     except TimeoutError:
-        text = format_pending_response_text(config.response_timeout_seconds)
+        text = format_pending_response_text(proposal.id, config.response_timeout_seconds)
         return {
             "content": [{"type": "text", "text": text}],
             "isError": False,
@@ -370,6 +407,54 @@ def handle_tools_call(
     }
 
 
+def handle_check_proposal(
+    params: dict[str, object],
+    config: ServerConfig,
+) -> dict[str, object]:
+    """Non-blocking poll of a queued proposal's decision, by id.
+
+    Never creates a Proposal (so `check-proposal` isn't in `TOOLS`); it only
+    reads the queue. Resolution order mirrors the synchronous path's terminal
+    step — a decided proposal is archived here exactly as `handle_tools_call`
+    archives it after `wait_for_response`, so `pending` proposals stay visible
+    to the operator until they're both decided *and* polled."""
+    args_raw = params.get("arguments", {})
+    if not isinstance(args_raw, dict):
+        raise _RpcClientError(ERR_INVALID_PARAMS, "tools/call 'arguments' must be an object")
+    proposal_id = args_raw.get("proposal_id")
+    if not isinstance(proposal_id, str) or not proposal_id.strip():
+        raise _RpcClientError(
+            ERR_INVALID_PARAMS,
+            "check-proposal: 'proposal_id' is required and must be a non-empty string",
+        )
+    proposal_id = proposal_id.strip()
+
+    try:
+        response = _sv.read_response(config.bottle_slug, proposal_id)
+    except FileNotFoundError:
+        # No decision yet — distinguish "still queued" from "unknown id".
+        try:
+            _sv.read_proposal(config.bottle_slug, proposal_id)
+        except FileNotFoundError:
+            return {
+                "content": [{"type": "text", "text": format_unknown_proposal_text(proposal_id)}],
+                "isError": True,
+            }
+        return {
+            "content": [{"type": "text", "text": format_still_pending_text(proposal_id)}],
+            "isError": False,
+        }
+
+    try:
+        _sv.archive_proposal(config.bottle_slug, proposal_id)
+    except OSError as e:
+        raise _RpcInternalError(f"failed to archive proposal: {e}") from e
+    return {
+        "content": [{"type": "text", "text": format_response_text(response)}],
+        "isError": response.status == _sv.STATUS_REJECTED,
+    }
+
+
 def format_response_text(response: "_sv.Response") -> str:
     """Pretty-print a Response for the tool's text content. The agent
     reads the text and decides whether to retry / give up / surface."""
@@ -382,12 +467,35 @@ def format_response_text(response: "_sv.Response") -> str:
     return "\n".join(lines)
 
 
-def format_pending_response_text(timeout_seconds: float) -> str:
+def format_pending_response_text(proposal_id: str, timeout_seconds: float) -> str:
+    """Grace-window timeout: the proposal stays queued, and the agent is
+    told the id so it can `check-proposal` instead of re-proposing."""
     return "\n".join([
         "status: pending",
+        f"proposal_id: {proposal_id}",
         (
-            "notes: operator response timed out after "
-            f"{timeout_seconds:g}s; proposal remains queued"
+            f"notes: no operator decision within {timeout_seconds:g}s; the "
+            "proposal remains queued. Poll it (do not re-propose) by calling "
+            f"`check-proposal` with proposal_id={proposal_id!r}."
+        ),
+    ])
+
+
+def format_still_pending_text(proposal_id: str) -> str:
+    return "\n".join([
+        "status: pending",
+        f"proposal_id: {proposal_id}",
+        "notes: still queued; no operator decision yet. Call `check-proposal` again later.",
+    ])
+
+
+def format_unknown_proposal_text(proposal_id: str) -> str:
+    return "\n".join([
+        "status: unknown",
+        f"proposal_id: {proposal_id}",
+        (
+            "notes: no queued proposal with this id for this bottle — the id "
+            "may be wrong, or the proposal was already resolved and read."
         ),
     ])
 
@@ -482,6 +590,11 @@ class MCPHandler(http.server.BaseHTTPRequestHandler):
             # — silently dropping base routes like api.anthropic.com on approval.
             if req.params.get("name") == _sv.TOOL_LIST_EGRESS_ROUTES:
                 return self._resolved_routes_payload()
+            # `check-proposal` is a non-blocking read of the calling bottle's
+            # own queue — attributed by source IP like a proposal, but it
+            # never queues or blocks.
+            if req.params.get("name") == _sv.TOOL_CHECK_PROPOSAL:
+                return handle_check_proposal(req.params, self._attributed_config(config))
             # Attribute the proposal to the source-IP-resolved bottle, so the one
             # shared server queues each bottle's proposal under its own slug.
             return handle_tools_call(req.params, self._attributed_config(config))

bot_bottle/supervise_types.py

@@ -20,6 +20,10 @@ TOOL_EGRESS_ALLOW = "egress-allow"
 TOOL_GITLEAKS_ALLOW = "gitleaks-allow"
 TOOL_EGRESS_TOKEN_ALLOW = "egress-token-allow"
 TOOL_LIST_EGRESS_ROUTES = "list-egress-routes"
+# Read-only agent tool: poll a queued proposal for the operator's decision
+# without blocking or re-proposing. It never becomes a `Proposal.tool` (no
+# queue record is created for it), so it is intentionally NOT in `TOOLS`.
+TOOL_CHECK_PROPOSAL = "check-proposal"
 TOOLS: tuple[str, ...] = (
     TOOL_EGRESS_ALLOW,
     TOOL_EGRESS_BLOCK,
@@ -156,6 +160,7 @@ __all__ = [
     "TOOLS",
     "TOOL_EGRESS_ALLOW",
     "TOOL_EGRESS_BLOCK",
+    "TOOL_CHECK_PROPOSAL",
     "TOOL_EGRESS_TOKEN_ALLOW",
     "TOOL_GITLEAKS_ALLOW",
     "TOOL_LIST_EGRESS_ROUTES",

docs/prds/prd-new-nonblocking-supervise.md

@@ -0,0 +1,125 @@
+# PRD prd-new: Non-blocking supervise (async approval + proposal polling)
+
+- **Status:** Draft
+- **Author:** didericis
+- **Created:** 2026-07-18
+- **Issue:** #412
+
+## Summary
+
+The per-bottle supervise MCP server (`bot_bottle/supervise_server.py`)
+answers `tools/call` **synchronously**: it queues the agent's proposal and
+blocks the tool call polling for the operator's decision. On timeout it
+returns `status: pending` and leaves the proposal queued — but it hands the
+agent **no proposal id** and offers **no way to poll a specific pending
+proposal**, so the only way to learn the outcome is to re-propose (a
+duplicate).
+
+This PRD makes the MCP flow non-blocking and pollable, so an approval can
+happen out-of-band (a human taking minutes-to-hours in a review console)
+without holding an HTTP request open or wedging the agent:
+
+1. Include the `proposal_id` in the `pending` response.
+2. Add a `check-proposal` MCP tool: a non-blocking status lookup by
+   proposal id.
+3. Keep the short synchronous grace window for the common "operator is
+   right there" fast path.
+
+## Problem
+
+`handle_tools_call` → `_sv.wait_for_response(...)` blocks up to
+`SUPERVISE_RESPONSE_TIMEOUT_SECONDS` (default 30s). Two problems follow:
+
+- **Human latency ≠ tool-call latency.** A real review — rendered diff,
+  RBAC routing to an approver, someone tapping approve on their phone — is
+  minutes-to-hours. Holding the MCP request open that long is fragile
+  (proxy/keepalive timeouts, the mitmproxy egress hop, and the agent
+  harness's own tool-call timeout, which a long block can trip and stall
+  the whole turn).
+- **No resume path.** The pending fallback already exists, but without a
+  proposal id and a poll tool the agent can't reconnect to that specific
+  decision — it re-proposes, duplicating the queue entry.
+
+This is also the precondition for the planned web-console human-review
+flow (RBAC, audit retention, mobile) — see issue #412.
+
+**Safety note:** the MCP tools only *propose* policy changes; enforcement
+stays at the egress proxy and the git-gate. Returning early on `pending`
+therefore opens no hole — the agent still cannot egress or push anything
+unapproved.
+
+## Goals / success criteria
+
+- A `pending` MCP response carries the `proposal_id`.
+- An agent can call `check-proposal(proposal_id)` and get the current
+  state (`pending` | `approved` | `modified` | `rejected`) **without
+  blocking** and **without creating a new proposal**.
+- The synchronous fast path (operator approves within the grace window) is
+  unchanged: the first `tools/call` still returns the decision directly.
+- No change to enforcement, attribution (source-IP → bottle), or the
+  operator-side queue/response schema.
+
+## Non-goals
+
+- The git-gate `pre-receive` path (it is synchronous by nature and cannot
+  poll — its async variant is reject-fast + re-push; tracked as a
+  follow-up).
+- Backpressure / in-flight-proposal caps.
+- MCP server→client notifications (event-driven resume).
+- Any web-console UI (this PRD is the protocol groundwork it needs).
+
+## Design
+
+### `pending` response carries the id
+
+`handle_tools_call`'s timeout branch formats the pending text with the
+`proposal.id` and a pointer to `check-proposal`, so the agent knows what to
+poll.
+
+### `check-proposal` tool
+
+A new read-only MCP tool (`TOOL_CHECK_PROPOSAL = "check-proposal"`),
+attributed to the calling bottle by source IP exactly like the proposal
+tools. Input: `{ "proposal_id": string }`. Behavior:
+
+1. `read_response(slug, id)` →
+   - **found**: archive the proposal (same terminal step the synchronous
+     path takes) and return the decision via `format_response_text`;
+     `isError` iff rejected.
+2. **not found** → `read_proposal(slug, id)` →
+   - **found**: still queued → return `status: pending`.
+   - **not found**: unknown id, or already resolved-and-archived (e.g. a
+     second poll) → return `status: unknown`, `isError: true`.
+
+Both lookups already raise `FileNotFoundError` when absent
+(`queue_store.py`), so the handler needs no new store methods. `check-`
+`proposal` is the only path (besides the synchronous response) that
+archives, so a proposal that times out to `pending` stays visible to the
+operator until it is decided and then polled.
+
+### Grace window
+
+Left at the existing 30s default (`SUPERVISE_RESPONSE_TIMEOUT_SECONDS`),
+which doubles as the instant-approve fast path. Tuning it down is an
+operator setting, not a code change; noted for the console rollout.
+
+## Implementation chunks
+
+1. **(this PR)** `TOOL_CHECK_PROPOSAL` constant; `check-proposal` tool
+   definition + `handle_check_proposal`; dispatch wiring; `proposal_id` in
+   the pending text; unit tests. Files: `bot_bottle/supervise_types.py`,
+   `bot_bottle/supervise.py` (re-export), `bot_bottle/supervise_server.py`,
+   `tests/unit/test_supervise_server.py`.
+2. **(follow-up)** git-gate `pre-receive` reject-fast + re-push.
+3. **(follow-up)** per-bottle in-flight-proposal backpressure cap.
+4. **(follow-up)** MCP notifications for event-driven resume; web-console
+   review flow (RBAC, audit retention) on top.
+
+## Open questions
+
+- Should a resolved-but-unpolled proposal auto-archive after some TTL, or
+  only on poll? (Leaning: only on poll, so a decision is never lost to a
+  reaper before the agent sees it.)
+- Does the agent harness need an explicit "you have a pending proposal"
+  nudge, or is returning `pending` from the original call enough? (Deferred
+  to the notifications chunk.)

tests/unit/test_supervise_server.py

@@ -32,7 +32,9 @@ from bot_bottle.supervise_server import (
     _RpcError,
     _RpcInternalError,
     _response_timeout_from_env,
+    format_pending_response_text,
     format_response_text,
+    handle_check_proposal,
     handle_initialize,
     handle_tools_call,
     handle_tools_list,
@@ -218,6 +220,7 @@ class TestHandleToolsList(unittest.TestCase):
                 _sv.TOOL_EGRESS_ALLOW,
                 _sv.TOOL_EGRESS_BLOCK,
                 _sv.TOOL_LIST_EGRESS_ROUTES,
+                _sv.TOOL_CHECK_PROPOSAL,
             ]),
             sorted(names),
         )
@@ -484,9 +487,10 @@ class TestFormatResponseText(unittest.TestCase):
 
 class TestFormatPendingResponseText(unittest.TestCase):
     def test_formats_timeout_message(self):
-        text = supervise_server.format_pending_response_text(12.5)
+        text = supervise_server.format_pending_response_text("prop-9", 12.5)
         self.assertIn("status: pending", text)
         self.assertIn("12.5s", text)
+        self.assertIn("proposal_id: prop-9", text)
 
 
 # --- End-to-end HTTP sanity ------------------------------------------------
@@ -685,5 +689,129 @@ class TestResolvedRoutesPayload(unittest.TestCase):
             _handler(None)._resolved_routes_payload()
 
 
+class TestNonBlockingSupervise(unittest.TestCase):
+    """PRD prd-new / issue #412: pending responses carry the proposal id, and
+    `check-proposal` polls a queued proposal without blocking or re-proposing."""
+
+    _ROUTES = "routes:\n  - host: example.com\n"
+
+    def setUp(self):
+        self._tmp = tempfile.TemporaryDirectory(prefix="supervise-nonblock-test.")
+        self._home_patch = use_bottle_root(Path(self._tmp.name) / ".bot-bottle")
+        self.config = ServerConfig(bottle_slug="dev")
+        _qs.QueueStore("dev").migrate()
+        _as.AuditStore().migrate()
+
+    def tearDown(self):
+        self._home_patch()
+        self._tmp.cleanup()
+
+    def _seed_proposal(self) -> "_sv.Proposal":
+        p = _sv.Proposal.new(
+            bottle_slug="dev",
+            tool=_sv.TOOL_EGRESS_ALLOW,
+            proposed_file=self._ROUTES,
+            justification="need example.com",
+            current_file_hash=_sv.sha256_hex(self._ROUTES),
+        )
+        _sv.write_proposal(p)
+        return p
+
+    def _check(self, proposal_id: str) -> dict[str, object]:
+        return handle_check_proposal({"arguments": {"proposal_id": proposal_id}}, self.config)
+
+    # --- pending response carries the id ---
+
+    def test_pending_text_includes_id_and_pointer(self):
+        text = format_pending_response_text("abc-123", 30.0)
+        self.assertIn("status: pending", text)
+        self.assertIn("proposal_id: abc-123", text)
+        self.assertIn("check-proposal", text)
+
+    def test_tools_call_timeout_returns_pending_with_id_and_stays_queued(self):
+        # No responder → the grace window expires → pending, not blocked forever.
+        result = handle_tools_call(
+            {
+                "name": _sv.TOOL_EGRESS_ALLOW,
+                "arguments": {"routes_yaml": self._ROUTES, "justification": "x"},
+            },
+            ServerConfig(bottle_slug="dev", response_timeout_seconds=0.05),
+        )
+        self.assertFalse(result["isError"])  # type: ignore[index]
+        text = result["content"][0]["text"]  # type: ignore[index]
+        self.assertIn("status: pending", text)
+        pending = _sv.list_pending_proposals("dev")
+        self.assertEqual(1, len(pending))  # still queued, not archived
+        self.assertIn(pending[0].id, text)  # agent got the id to poll
+
+    # --- check-proposal poll ---
+
+    def test_check_returns_approved_and_archives(self):
+        p = self._seed_proposal()
+        _sv.write_response("dev", _sv.Response(proposal_id=p.id, status=_sv.STATUS_APPROVED, notes="ok"))
+        result = self._check(p.id)
+        self.assertFalse(result["isError"])
+        text = result["content"][0]["text"]  # type: ignore[index]
+        self.assertIn("status: approved", text)
+        self.assertIn("notes: ok", text)
+        with self.assertRaises(FileNotFoundError):  # archived on read
+            _sv.read_proposal("dev", p.id)
+
+    def test_check_rejected_sets_isError(self):
+        p = self._seed_proposal()
+        _sv.write_response("dev", _sv.Response(proposal_id=p.id, status=_sv.STATUS_REJECTED, notes="no"))
+        result = self._check(p.id)
+        self.assertTrue(result["isError"])
+        self.assertIn("status: rejected", result["content"][0]["text"])  # type: ignore[index]
+
+    def test_check_pending_when_no_decision_yet(self):
+        p = self._seed_proposal()
+        result = self._check(p.id)
+        self.assertFalse(result["isError"])
+        text = result["content"][0]["text"]  # type: ignore[index]
+        self.assertIn("status: pending", text)
+        self.assertIn(p.id, text)
+        self.assertEqual(1, len(_sv.list_pending_proposals("dev")))  # not archived
+
+    def test_check_unknown_id_is_error(self):
+        result = self._check("no-such-proposal")
+        self.assertTrue(result["isError"])
+        self.assertIn("status: unknown", result["content"][0]["text"])  # type: ignore[index]
+
+    def test_check_missing_id_raises(self):
+        with self.assertRaises(_RpcClientError) as cm:
+            handle_check_proposal({"arguments": {}}, self.config)
+        self.assertEqual(ERR_INVALID_PARAMS, cm.exception.code)
+
+    def test_check_empty_id_raises(self):
+        with self.assertRaises(_RpcClientError) as cm:
+            handle_check_proposal({"arguments": {"proposal_id": "   "}}, self.config)
+        self.assertEqual(ERR_INVALID_PARAMS, cm.exception.code)
+
+    def test_check_arguments_must_be_object(self):
+        with self.assertRaises(_RpcClientError) as cm:
+            handle_check_proposal({"arguments": []}, self.config)
+        self.assertEqual(ERR_INVALID_PARAMS, cm.exception.code)
+
+    def test_full_nonblocking_round_trip(self):
+        # 1. tools/call times out → pending with id
+        result = handle_tools_call(
+            {
+                "name": _sv.TOOL_EGRESS_ALLOW,
+                "arguments": {"routes_yaml": self._ROUTES, "justification": "x"},
+            },
+            ServerConfig(bottle_slug="dev", response_timeout_seconds=0.05),
+        )
+        pid = _sv.list_pending_proposals("dev")[0].id
+        self.assertIn(pid, result["content"][0]["text"])  # type: ignore[index]
+        # 2. operator decides out-of-band
+        _sv.write_response("dev", _sv.Response(proposal_id=pid, status=_sv.STATUS_APPROVED, notes="ok"))
+        # 3. agent resumes by polling — no re-proposing
+        poll = self._check(pid)
+        self.assertFalse(poll["isError"])
+        self.assertIn("status: approved", poll["content"][0]["text"])  # type: ignore[index]
+        self.assertEqual([], _sv.list_pending_proposals("dev"))  # resolved + archived
+
+
 if __name__ == "__main__":
     unittest.main()