diff --git a/harnesses/composites/workflow-script-nocp/v1/harness.yaml b/harnesses/composites/workflow-script-nocp/v1/harness.yaml
new file mode 100644
index 0000000..e3647b5
--- /dev/null
+++ b/harnesses/composites/workflow-script-nocp/v1/harness.yaml
@@ -0,0 +1,16 @@
+kind: composite
+name: workflow-script-nocp
+version: 1
+description: "Internal composite for kind: script nodes with cp_write=false (typed-workflows WF-COMP-31b, Option C). Brings the shared-variables filesystem context and the read-only project-repo clone, and NO CP credential: it layers neither cp-service-token/v1 (the AU-51 internal bearer) nor cp-write-token/v1 (the AU-55 per-step write token). Its only forge credential is repo-readonly/v1's read-only deploy key. Not model-bearing; the compiled shape is cli=\"shell\", params.cmd=<cmd>."
+
+# Top-down order (WF-COMP-31b / WF-COMP-34): shared-variables first, repo-readonly
+# LAST so its clone runs after the variable wiring and before the script starts.
+# Never gitea-ssh/v1 (bug 45a48685). repo-readonly/v1 cannot be dropped: the
+# entrypoint V2 guard trips when AGENT_REPO_URL is set and /workspace/project is
+# missing, and every shipped script template declares agent_repo.
+layers:
+  # spec/workflow-variables.md WV-19 / spec/harness.md HD-14 — agent-facing
+  # /variables/ context; provides the [shared-variables] tag.
+  - context: shared-variables/v1
+  # spec/typed-workflows.md WF-COMP-34 — read-only project-repo clone.
+  - context: repo-readonly/v1
diff --git a/harnesses/composites/workflow-script-write/v1/harness.yaml b/harnesses/composites/workflow-script-write/v1/harness.yaml
new file mode 100644
index 0000000..63f3dd5
--- /dev/null
+++ b/harnesses/composites/workflow-script-write/v1/harness.yaml
@@ -0,0 +1,16 @@
+kind: composite
+name: workflow-script-write
+version: 1
+description: "Internal composite for kind: script nodes with cp_write=true (typed-workflows WF-COMP-31c, Option C). Brings the shared-variables filesystem context, the AU-55 per-step CP write token (cp-write-token/v1 sets CP_WRITE_TOKEN_FILE; the dispatcher delivers the wfcw_ file into the script container only, AU-55b) and the read-only project-repo clone. Omits cp-service-token/v1: a cp_write=true container gets the AU-55 token only, never the AU-51 internal bearer. Not model-bearing; the compiled shape is cli=\"shell\", params.cmd=<cmd>."
+
+# Top-down order (WF-COMP-31c / WF-COMP-34): shared-variables, cp-write-token,
+# repo-readonly LAST. Never gitea-ssh/v1 (bug 45a48685) and never
+# cp-service-token/v1.
+layers:
+  # spec/workflow-variables.md WV-19 / spec/harness.md HD-14.
+  - context: shared-variables/v1
+  # spec/authentication.md AU-55 / AU-55b — env-only layer; exports
+  # CP_WRITE_TOKEN_FILE=/run/agent/cp-write-token/token.
+  - context: cp-write-token/v1
+  # spec/typed-workflows.md WF-COMP-34 — read-only project-repo clone.
+  - context: repo-readonly/v1
diff --git a/tests/invariants/test_workflow_script_option_c_composites.py b/tests/invariants/test_workflow_script_option_c_composites.py
new file mode 100644
index 0000000..116ed30
--- /dev/null
+++ b/tests/invariants/test_workflow_script_option_c_composites.py
@@ -0,0 +1,94 @@
+"""workflow-script-nocp/v1 and workflow-script-write/v1 (Option C, WF-COMP-31b/31c).
+
+Layer order is load-bearing: shared-variables first, repo-readonly LAST
+(WF-COMP-34), and neither composite may carry the AU-51 internal bearer
+(cp-service-token/v1) or the write-capable gitea-ssh/v1. Only the write
+composite carries the AU-55 per-step token layer.
+"""
+from __future__ import annotations
+
+from pathlib import Path
+
+import pytest
+import yaml
+
+from tests.invariants.forge_credentials import _layer_has_forge_credentials
+
+_ROOT = Path(__file__).resolve().parents[2] / "harnesses"
+_KIND_TO_DIR = {"context": "contexts", "capability": "capabilities", "composite": "composites"}
+
+_NOCP = [{"context": "shared-variables/v1"}, {"context": "repo-readonly/v1"}]
+_WRITE = [
+    {"context": "shared-variables/v1"},
+    {"context": "cp-write-token/v1"},
+    {"context": "repo-readonly/v1"},
+]
+
+
+def _load(kind_dir: str, name: str) -> dict:
+    return yaml.safe_load((_ROOT / kind_dir / name / "v1" / "harness.yaml").read_text())
+
+
+def _merged_env(doc: dict) -> dict:
+    env: dict = dict(doc.get("env") or {})
+    for layer in doc["layers"]:
+        (kind, ref), = layer.items()
+        env.update(_load(_KIND_TO_DIR[kind], ref.split("/")[0]).get("env") or {})
+    return env
+
+
+@pytest.mark.parametrize(
+    "name,expected", [("workflow-script-nocp", _NOCP), ("workflow-script-write", _WRITE)]
+)
+def test_composite_layers_exact_order_repo_readonly_last(name, expected):
+    doc = _load("composites", name)
+    assert doc["kind"] == "composite"
+    assert doc["name"] == name
+    assert doc["version"] == 1
+    assert doc["layers"] == expected
+    assert doc["layers"][-1] == {"context": "repo-readonly/v1"}
+
+
+@pytest.mark.parametrize("name", ["workflow-script-nocp", "workflow-script-write"])
+def test_composite_never_carries_internal_bearer_or_write_capable_forge_key(name):
+    doc = _load("composites", name)
+    names = [next(iter(layer.values())).split("/")[0] for layer in doc["layers"]]
+    assert "cp-service-token" not in names
+    assert "gitea-ssh" not in names
+    for layer in doc["layers"]:
+        (kind, ref), = layer.items()
+        sub = _load(_KIND_TO_DIR[kind], ref.split("/")[0])
+        if _layer_has_forge_credentials(sub):
+            assert sub.get("write_targets") == [], f"{ref} must be read-only (HC-11)"
+
+
+@pytest.mark.parametrize("name", ["workflow-script-nocp", "workflow-script-write"])
+def test_every_referenced_layer_exists_and_names_match(name):
+    doc = _load("composites", name)
+    for layer in doc["layers"]:
+        (kind, ref), = layer.items()
+        lname, ver = ref.split("/")
+        path = _ROOT / _KIND_TO_DIR[kind] / lname / ver / "harness.yaml"
+        assert path.exists(), path
+        assert yaml.safe_load(path.read_text())["name"] == lname
+
+
+def test_nocp_composite_exports_no_cp_credential_env():
+    env = _merged_env(_load("composites", "workflow-script-nocp"))
+    assert "CP_SERVICE_TOKEN_FILE" not in env
+    assert "CP_WRITE_TOKEN_FILE" not in env
+    assert env["WORKFLOW_VARIABLES_ROOT"] == "/variables"
+
+
+def test_write_composite_env_contract():
+    env = _merged_env(_load("composites", "workflow-script-write"))
+    assert env["CP_WRITE_TOKEN_FILE"] == "/run/agent/cp-write-token/token"
+    assert "CP_SERVICE_TOKEN_FILE" not in env
+    assert env["WORKFLOW_VARIABLES_ROOT"] == "/variables"
+
+
+def test_workflow_script_write_composite_layers_and_env_contract():
+    """Spec WF-COMP-31c test handle (framework repo)."""
+    doc = _load("composites", "workflow-script-write")
+    assert doc["layers"] == _WRITE
+    assert _merged_env(doc)["CP_WRITE_TOKEN_FILE"] == "/run/agent/cp-write-token/token"