diff --git a/pyproject.toml b/pyproject.toml
index b8a67e4..ce4eb2c 100755
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "sprintctl"
-version = "0.3.1"
+version = "0.3.2"
 requires-python = ">=3.11"
 dependencies = [
     "click>=8.1",
diff --git a/sprintctl/__init__.py b/sprintctl/__init__.py
index 0a0a168..3f646bd 100755
--- a/sprintctl/__init__.py
+++ b/sprintctl/__init__.py
@@ -1,4 +1,4 @@
-__version__ = "0.3.1"
+__version__ = "0.3.2"
 
 # Keep these identifiers stable: the doctor command compares the running
 # package with the capabilities declared by a checked-out source tree.
diff --git a/sprintctl/served.py b/sprintctl/served.py
index e438a44..d1f0e28 100644
--- a/sprintctl/served.py
+++ b/sprintctl/served.py
@@ -23,6 +23,7 @@
 from __future__ import annotations
 
 import asyncio
+import uuid
 from typing import Any
 
 from . import reservation as _reservation
@@ -275,10 +276,32 @@ def read_next_work(
 
 
 def reservation_operation(
-    served_profile: ServedProfile, operation: str, arguments: dict[str, Any], *, repo_id: str
+    served_profile: ServedProfile,
+    operation: str,
+    arguments: dict[str, Any],
+    *,
+    repo_id: str,
+    idempotency_key: str | None = None,
 ) -> dict[str, Any]:
-    """Invoke one v0.3 reservation operation through the served authority."""
-    return asyncio.run(_invoke_operation(served_profile, operation, arguments, repo_id=repo_id))
+    """Invoke one v0.3 reservation operation through the served authority.
+
+    Every ``work.reservation.*`` operation is declared ``idempotency: required``
+    by the adapter, so the authority rejects a call without a key
+    (``idempotency-key-required``) *after* the authority check has passed --
+    which is how a correctly granted identity was first seen failing here. A
+    reservation is a coordination signal, and ``touch`` in particular must be
+    able to advance ``last_activity_at`` on every call, so the default key is
+    unique per invocation (the same convention as the per-event key used by
+    ``publish_events``) rather than derived from the arguments. Callers that
+    retry a single logical call pass their own key to deduplicate. Reads
+    (``work.read.reservation``) are never keyed.
+    """
+    kwargs: dict[str, Any] = {"repo_id": repo_id}
+    if operation.startswith("work.reservation."):
+        # Only the mutations are keyed: ``work.read.reservation`` travels
+        # through here too and the authority rejects a key on a read.
+        kwargs["idempotency_key"] = idempotency_key or uuid.uuid4().hex
+    return asyncio.run(_invoke_operation(served_profile, operation, arguments, **kwargs))
 
 
 def read_records(
diff --git a/tests/test_served.py b/tests/test_served.py
index f2b9b66..abbdec9 100644
--- a/tests/test_served.py
+++ b/tests/test_served.py
@@ -287,6 +287,25 @@ def test_reservation_operation_sends_credential_free_shape(fake_vuoro_client):
     assert "claim_token" not in args
 
 
+def test_reservation_operation_always_sends_an_idempotency_key(fake_vuoro_client):
+    """Every work.reservation.* operation is ``idempotency: required`` on the
+    adapter, and the authority rejects a keyless call only *after* the
+    authority check -- so a missing key looked like a grant problem in the
+    field. Default keys are unique per call (touch must advance activity every
+    time); an explicit key is passed through for callers that retry."""
+    profile = _profile()
+    args = {"item_id": 5, "actor": "worker", "session_id": "session-1"}
+    served.reservation_operation(profile, "work.reservation.reserve", dict(args), repo_id="repo-x")
+    served.reservation_operation(profile, "work.reservation.touch", dict(args), repo_id="repo-x")
+    served.reservation_operation(
+        profile, "work.reservation.release", dict(args), repo_id="repo-x", idempotency_key="retry-7"
+    )
+    keys = [inv[2].get("idempotency_key") for client in fake_vuoro_client.instances for inv in client.invocations]
+    assert len(keys) == 3 and all(keys), keys
+    assert keys[0] != keys[1]
+    assert keys[2] == "retry-7"
+
+
 def test_item_note_sends_full_shape_and_never_an_actor_field(fake_vuoro_client):
     profile = _profile()
     result = served.item_note(
diff --git a/uv.lock b/uv.lock
index 2f7421b..3431894 100755
--- a/uv.lock
+++ b/uv.lock
@@ -517,7 +517,7 @@ wheels = [
 
 [[package]]
 name = "sprintctl"
-version = "0.3.1"
+version = "0.3.2"
 source = { editable = "." }
 dependencies = [
     { name = "click" },
diff --git a/verification/validate_release_contract.py b/verification/validate_release_contract.py
index 673947a..664182d 100644
--- a/verification/validate_release_contract.py
+++ b/verification/validate_release_contract.py
@@ -14,7 +14,7 @@
 
 
 ROOT = Path(__file__).resolve().parents[1]
-RELEASE_VERSION = "0.3.1"
+RELEASE_VERSION = "0.3.2"
 ADAPTER_NAME = "vuoro-adapter-kit"
 ADAPTER_DIGEST_RE = re.compile(r"^sha256=(?P<digest>[0-9a-f]{64})$")
 ADAPTER_PATH_RE = re.compile(