diff --git a/.github/workflows/consent-plane-surface.yml b/.github/workflows/consent-plane-surface.yml
new file mode 100644
index 00000000000..901697660b3
--- /dev/null
+++ b/.github/workflows/consent-plane-surface.yml
@@ -0,0 +1,17 @@
+name: Consent Plane Surface
+on:
+  pull_request:
+  push:
+    branches: [main]
+permissions:
+  contents: read
+jobs:
+  verify:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with: { python-version: '3.x' }
+      - run: python -m pip install pyyaml
+      - run: python consent-plane/self_test.py
+      - run: python consent-plane/verify_surface.py
diff --git a/consent-plane/self_test.py b/consent-plane/self_test.py
new file mode 100644
index 00000000000..98b736230a3
--- /dev/null
+++ b/consent-plane/self_test.py
@@ -0,0 +1,21 @@
+#!/usr/bin/env python3
+"""Prove verify_surface fires both ways: passes on the real envelope, fires when
+the containment is weakened or the surface_id is switched."""
+from __future__ import annotations
+import copy, sys
+from pathlib import Path
+sys.path.insert(0, str(Path(__file__).resolve().parent))
+import verify_surface as v  # noqa: E402
+
+cp = v.load()
+assert v.check(cp) == [], f"real envelope should pass: {v.check(cp)}"
+
+if cp.get("space_deny"):
+    weak = copy.deepcopy(cp); weak["space_deny"] = weak["space_deny"][:-1]
+    assert v.check(weak), "verifier did not fire on a weakened space_deny"
+
+switched = copy.deepcopy(cp)
+switched["surface_id"] = "browser" if cp["surface_id"] != "browser" else "terminal"
+assert v.check(switched), "verifier did not fire on a switched surface_id"
+
+print("OK: verify_surface fires both ways (holds on real; catches weakening + switch).")
diff --git a/consent-plane/surface.yaml b/consent-plane/surface.yaml
new file mode 100644
index 00000000000..df67a754163
--- /dev/null
+++ b/consent-plane/surface.yaml
@@ -0,0 +1,9 @@
+# Consent-plane surface envelope. Conforms to socioprophet-agent-standards
+# consent-plane/001 + sourceos-spec isolation-spaces-and-taints. Enforced by
+# consent-plane/verify_surface.py (consent-plane-surface CI).
+surface_id: terminal
+conforms_to: socioprophet-agent-standards/standards/consent-plane/surfaces_v1.yaml#terminal
+purposes: [discover, implement, verify]
+deny_purposes: [egress, operate]        # a terminal must not egress or operate live infra
+data_classes: [source-and-config, first-party-source]
+space_deny: [kernel-space, system-space]  # no OS-core / infra ring from a shell
diff --git a/consent-plane/verify_surface.py b/consent-plane/verify_surface.py
new file mode 100644
index 00000000000..1395500f767
--- /dev/null
+++ b/consent-plane/verify_surface.py
@@ -0,0 +1,72 @@
+#!/usr/bin/env python3
+"""Enforce this repo's consent-plane surface envelope (fail-closed).
+
+This repo IS the terminal surface; EXPECTED_SURFACE pins it so surface.yaml
+cannot be silently switched to a weaker surface. Reads consent-plane/surface.yaml
+and asserts the hard invariants. Proven both ways by consent-plane/self_test.py.
+Conforms to socioprophet-agent-standards consent-plane/001 + sourceos-spec
+isolation-spaces-and-taints.
+"""
+from __future__ import annotations
+import sys
+from pathlib import Path
+try:
+    import yaml  # type: ignore
+except Exception as exc:  # pragma: no cover
+    raise SystemExit("PyYAML is required (python -m pip install pyyaml)") from exc
+
+EXPECTED_SURFACE = "terminal"
+
+# Minimum containment each surface MUST assert (subset checks).
+EXPECTED = {
+    "terminal": {"deny_purposes": {"egress", "operate"},
+                 "space_deny": {"kernel-space", "system-space"}},
+    "notes":    {"deny_purposes": {"egress", "operate"},
+                 "space_deny": {"kernel-space", "system-space", "data-namespace"},
+                 "consent_required": "per-purpose"},
+    "browser":  {"deny_purposes": {"implement", "operate"},
+                 "space_deny": {"kernel-space", "system-space", "user-space", "data-namespace"},
+                 "untrusted_input": True},
+}
+
+
+def check(cp: dict) -> list[str]:
+    errors: list[str] = []
+    sid = cp.get("surface_id")
+    if sid != EXPECTED_SURFACE:
+        return [f"surface_id must be {EXPECTED_SURFACE!r} for this repo, got {sid!r}"]
+    for key, want in EXPECTED[sid].items():
+        got = cp.get(key)
+        if isinstance(want, set):
+            if not isinstance(got, list):
+                errors.append(f"{key} must be a list, got {type(got).__name__}")
+                continue
+            missing = want - set(got)
+            if missing:
+                errors.append(f"{key} must include {sorted(want)}; missing {sorted(missing)}")
+        elif got != want:
+            errors.append(f"{key} must be {want!r}, got {got!r}")
+    return errors
+
+
+def load() -> dict:
+    cfg = Path(__file__).resolve().parent / "surface.yaml"
+    cp = yaml.safe_load(cfg.read_text())
+    if not isinstance(cp, dict):
+        raise SystemExit("consent-plane/surface.yaml top-level must be a mapping")
+    return cp
+
+
+def main() -> int:
+    errors = check(load())
+    if errors:
+        print(f"FAIL: {EXPECTED_SURFACE} surface envelope violated:", file=sys.stderr)
+        for e in errors:
+            print(f"  - {e}", file=sys.stderr)
+        return 1
+    print(f"OK: {EXPECTED_SURFACE} surface envelope holds.")
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())