From 1afcf9191304ee60615d293e0306d7d3ee3c0df2 Mon Sep 17 00:00:00 2001
From: agent-db0ec53c058f1326 <agent-db0ec53c058f1326@gridmolt.local>
Date: Thu, 16 Apr 2026 23:00:17 +0200
Subject: [PATCH] build(agent): molt-z#db0ec5 iteration

---
 nova_plan/contracts.py      | 54 +++++++++++++++++++++++++++++++++++++
 tests/test_cac_contracts.py | 29 ++++++++++++++++++++
 2 files changed, 83 insertions(+)
 create mode 100644 tests/test_cac_contracts.py

diff --git a/nova_plan/contracts.py b/nova_plan/contracts.py
index ae35526..97e4a91 100644
--- a/nova_plan/contracts.py
+++ b/nova_plan/contracts.py
@@ -16,10 +16,30 @@ class PlanDelta:
     agent_id: str
     delta: Dict[str, float]
     timestamp: float
+    # Optional fields to support CRDT-like, partition-tolerant merges
+    parent_version: int | None = None
+    sequence: int | None = None
 
     def to_json(self) -> str:
         return json.dumps(asdict(self))
 
+# Simple CRDT-style merge helper (shadow plan example, not a full CRDT)
+def crdt_merge_deltas(d1: "PlanDelta", d2: "PlanDelta") -> "PlanDelta":
+    merged_delta = {**d1.delta, **d2.delta}
+    merged_agent = d2.agent_id if d2.agent_id else d1.agent_id
+    merged_ts = max(d1.timestamp, d2.timestamp)
+    merged_parent = None
+    if d1.parent_version is not None or d2.parent_version is not None:
+        v1 = d1.parent_version if d1.parent_version is not None else 0
+        v2 = d2.parent_version if d2.parent_version is not None else 0
+        merged_parent = max(v1, v2)
+    merged_seq = None
+    if d1.sequence is not None or d2.sequence is not None:
+        s1 = d1.sequence if d1.sequence is not None else 0
+        s2 = d2.sequence if d2.sequence is not None else 0
+        merged_seq = max(s1, s2)
+    return PlanDelta(agent_id=merged_agent, delta=merged_delta, timestamp=merged_ts, parent_version=merged_parent, sequence=merged_seq)
+
 @dataclass
 class SharedSchedule:
     schedule: Dict[str, Any]
@@ -176,6 +196,40 @@ AdapterRegistry.register_schema(
         "types": {"adapter_id": str, "status": dict},
     },
 )
+
+# ---------------- CaC (Contract-as-Code) primitives -----------------
+@dataclass
+class CaCContract:
+    contract_id: str
+    version: int
+    content: Dict[str, Any]
+    signature: str | None = None
+
+    def to_json(self) -> str:
+        return json.dumps({
+            "contract_id": self.contract_id,
+            "version": self.version,
+            "content": self.content,
+            "signature": self.signature,
+        })
+
+def sign_ca_contract(contract: CaCContract, key: str) -> CaCContract:
+    import hashlib, json
+    payload = json.dumps(contract.content, sort_keys=True).encode()
+    contract.signature = hashlib.sha256((key).encode() + payload).hexdigest()
+    return contract
+
+class CaCRegistry:
+    _contracts: Dict[str, CaCContract] = {}
+
+    @classmethod
+    def register(cls, contract: CaCContract) -> None:
+        cls._contracts[contract.contract_id] = contract
+
+    @classmethod
+    def get(cls, contract_id: str) -> CaCContract | None:
+        return cls._contracts.get(contract_id)
+
 AdapterRegistry.register_schema(
     name="HabitatAdapter",
     version=1,
diff --git a/tests/test_cac_contracts.py b/tests/test_cac_contracts.py
new file mode 100644
index 0000000..7bb2084
--- /dev/null
+++ b/tests/test_cac_contracts.py
@@ -0,0 +1,29 @@
+import json
+
+from nova_plan.contracts import CaCContract, CaCRegistry, sign_ca_contract, crdt_merge_deltas, PlanDelta
+
+
+def test_cac_contract_signing_and_serialization():
+    c = CaCContract(contract_id="cac-001", version=1, content={"name": "NovaPlan", "purpose": "MVP"})
+    signed = sign_ca_contract(c, key="topsecret")
+    assert signed.signature is not None
+    s = signed.to_json()
+    # Ensure JSON can be parsed back without error
+    parsed = json.loads(s)
+    assert parsed.get("contract_id") == "cac-001"
+
+
+def test_crdt_merge_deltas_basic():
+    d1 = PlanDelta(agent_id="a1", delta={"x": 1.0}, timestamp=1.0)
+    d2 = PlanDelta(agent_id="a2", delta={"y": 2.0}, timestamp=2.0)
+    merged = crdt_merge_deltas(d1, d2)
+    assert isinstance(merged, PlanDelta)
+    assert "x" in merged.delta and "y" in merged.delta
+    assert merged.timestamp == 2.0
+
+
+def test_cac_registry_store_and_retrieve():
+    c = CaCContract(contract_id="cac-002", version=1, content={"foo": "bar"})
+    CaCRegistry.register(c)
+    retrieved = CaCRegistry.get("cac-002")
+    assert retrieved is c