Verify the OpenBao read-boundary live; ship the invariant

The operator token was not expired after all -- `bao policy read` succeeded, so
the deployed policy is now compared directly instead of the file. Three
corrections to RISK-F-0009, which was filed static:

1. Six high-risk lanes are uncovered, not eight. The finding counted
   openbao-api-key (a path pattern) and ops-warden-warden-sign-token (a broker
   grant, not KV) among the concrete uncovered paths, while its own prose said
   the first was a pattern. Five lanes have no address for a policy to deny.
2. Coverage holds at 6 of 17 against the live policy.
3. The deployed policy has drifted from the file: the file denies
   platform/workloads/core-hub/runtime, the server does not. No ops-warden lane
   maps there so our numbers are unchanged, but it proves the file was never a
   safe proxy for the server -- which is what the finding flagged as unconfirmed.

scripts/check_agent_read_boundary.py is the invariant RISK-F-0009 asked for
rather than a one-off audit: it fails when a high-risk lane has no corresponding
deny. Capabilities-only by construction -- it reads the policy document, never a
secret value, and never mints a token.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

scripts/check_agent_read_boundary.py

@@ -0,0 +1,165 @@
+#!/usr/bin/env python3
+"""Verify the OpenBao half of the agent read-boundary (ADR-0004, WARDEN-WP-0032-T06).
+
+`warden access` exits 7 on every `risk: high` lane, but that only protects the
+ops-warden path. The OpenBao policy `agent-high-risk-boundary` is what protects a
+direct `bao kv get` -- the actual 2026-07-16 disclosure vector. This script
+compares the high-risk lanes in the routing catalog against the paths that policy
+actually denies.
+
+Read-only and capabilities-only by construction: it reads the *policy document*
+and lane metadata. It never reads a secret value, and it never mints a token.
+See `.claude/rules/credential-routing.md` -- verifying a lane with a read is the
+mistake this whole control exists to prevent.
+
+Prefers the policy deployed on the server (`bao policy read`); falls back to the
+file in railiance-platform and says loudly that it did, because deployment drift
+is exactly what this check exists to catch.
+
+Exit codes: 0 every high-risk lane with a concrete path is denied; 1 at least one
+is not; 2 the policy could not be obtained from either source.
+"""
+
+from __future__ import annotations
+
+import argparse
+import json
+import os
+import re
+import subprocess
+import sys
+from pathlib import Path
+
+REPO = Path(__file__).resolve().parent.parent
+CATALOG = REPO / "registry" / "routing" / "catalog.yaml"
+POLICY_NAME = "agent-high-risk-boundary"
+POLICY_FILE = Path.home() / "railiance-platform" / "openbao" / "policies" / f"{POLICY_NAME}.hcl"
+
+# A path_template with a placeholder is a pattern, not an address -- it names the
+# shape of a lane rather than one secret, so there is nothing for a policy to deny.
+PLACEHOLDER = re.compile(r"[<>{}]|\*")
+
+
+def read_deployed_policy() -> tuple[str | None, str]:
+    """Return (policy_text, source). Server first, file second, neither third."""
+    try:
+        proc = subprocess.run(
+            ["bao", "policy", "read", "-format=json", POLICY_NAME],
+            capture_output=True, text=True, timeout=20,
+        )
+    except (FileNotFoundError, subprocess.TimeoutExpired) as exc:
+        server_err = str(exc)
+    else:
+        if proc.returncode == 0:
+            try:
+                return json.loads(proc.stdout)["policy"], "server"
+            except (json.JSONDecodeError, KeyError):
+                return proc.stdout, "server"
+        server_err = (proc.stderr or proc.stdout).strip().splitlines()[:1]
+        server_err = server_err[0] if server_err else f"exit {proc.returncode}"
+
+    if POLICY_FILE.exists():
+        print(f"  ! could not read the deployed policy ({server_err})")
+        print(f"  ! falling back to the FILE at {POLICY_FILE}")
+        print("  ! deployment drift cannot be detected in this mode\n")
+        return POLICY_FILE.read_text(), "file"
+    return None, f"unavailable ({server_err})"
+
+
+def denied_data_paths(policy_text: str) -> set[str]:
+    """Paths the policy denies. Only a `deny` on a KV *data* path is a read-boundary."""
+    denied: set[str] = set()
+    for match in re.finditer(
+        r'path\s+"([^"]+)"\s*\{[^}]*?capabilities\s*=\s*\[([^\]]*)\]',
+        policy_text, re.DOTALL,
+    ):
+        path, caps = match.group(1), match.group(2)
+        if "deny" in {c.strip().strip('"\'') for c in caps.split(",")}:
+            denied.add(path)
+    return denied
+
+
+def to_data_path(path_template: str) -> str | None:
+    """Catalog path -> KV v2 data path. `<mount>/rest` -> `<mount>/data/rest`."""
+    if PLACEHOLDER.search(path_template) or " " in path_template:
+        return None
+    mount, _, rest = path_template.partition("/")
+    return f"{mount}/data/{rest}" if rest else None
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("--json", action="store_true", help="machine-readable output")
+    args = parser.parse_args()
+
+    import yaml  # local import so --help works without the dep
+
+    entries = yaml.safe_load(CATALOG.read_text())["entries"]
+    high = [e for e in entries if e.get("risk") == "high"]
+
+    policy_text, source = read_deployed_policy()
+    if policy_text is None:
+        print(f"FAIL: policy {POLICY_NAME} could not be obtained from server or file: {source}")
+        print("  Run `bao login -method=oidc`, or check out railiance-platform.")
+        return 2
+
+    denied = denied_data_paths(policy_text)
+
+    covered, uncovered, no_address = [], [], []
+    for entry in high:
+        template = entry.get("path_template")
+        data_path = to_data_path(template) if template else None
+        if data_path is None:
+            no_address.append(entry["id"])
+        elif data_path in denied:
+            covered.append((entry["id"], data_path))
+        else:
+            uncovered.append((entry["id"], data_path))
+
+    if args.json:
+        print(json.dumps({
+            "policy": POLICY_NAME,
+            "policy_source": source,
+            "high_risk_lanes": len(high),
+            "denied_data_paths": sorted(denied),
+            "covered": [{"id": i, "path": p} for i, p in covered],
+            "uncovered": [{"id": i, "path": p} for i, p in uncovered],
+            "no_concrete_address": no_address,
+            "ok": not uncovered,
+        }, indent=2))
+        return 1 if uncovered else 0
+
+    print(f"agent read-boundary — OpenBao half ({POLICY_NAME})\n")
+    print(f"  policy source:        {source}"
+          + ("   <-- live" if source == "server" else "   <-- NOT the deployed policy"))
+    print(f"  high-risk lanes:      {len(high)}")
+    print(f"  denied data paths:    {len(denied)}")
+    print(f"  covered:              {len(covered)}")
+    print(f"  NOT covered:          {len(uncovered)}")
+    print(f"  no concrete address:  {len(no_address)}\n")
+
+    if covered:
+        print("COVERED — a direct `bao kv get` is denied for an agent token")
+        for lane_id, path in sorted(covered):
+            print(f"  {lane_id:34} {path}")
+        print()
+    if uncovered:
+        print("NOT COVERED — graded high, but the policy does not deny the data path")
+        for lane_id, path in sorted(uncovered):
+            print(f"  {lane_id:34} {path}")
+        print()
+    if no_address:
+        print("NO CONCRETE ADDRESS — a pattern or a non-KV lane, nothing to deny")
+        print("  " + ", ".join(sorted(no_address)) + "\n")
+
+    if uncovered:
+        print(f"RESULT: FAIL — {len(uncovered)} high-risk lane(s) outside the OpenBao boundary.")
+        print("  The policy is railiance-platform's; ops-warden reports rather than amends"
+              " (RISK-F-0004).")
+        return 1
+    print("RESULT: PASS — every high-risk lane with a concrete path is denied.")
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())