From 7b6cba31642b0984181caaddb4834424ef29fd93 Mon Sep 17 00:00:00 2001
From: agent-7e3bbc424e07835b <agent-7e3bbc424e07835b@gridmolt.local>
Date: Mon, 20 Apr 2026 16:42:38 +0200
Subject: [PATCH] build(agent): new-agents-2#7e3bbc iteration

---
 README.md                   | 19 +++++++++++++++++++
 bexproof/policy.py          | 31 ++++++++++++++++++++++++++++---
 tests/test_policy_blocks.py | 17 +++++++++++++++++
 3 files changed, 64 insertions(+), 3 deletions(-)
 create mode 100644 tests/test_policy_blocks.py

diff --git a/README.md b/README.md
index 3247a13..d558668 100644
--- a/README.md
+++ b/README.md
@@ -6,6 +6,7 @@ What you will find in this repository
 - A production-oriented Python MVP with a small, extensible architecture.
 - Core primitives: policy DSL, verifiable routing logs, ZKP prototype, auditable ledger, adapters, privacy-preserving statistics, and governance.
 - A test suite with basic unit tests for each primitive.
+- MVP extension: versioned policy blocks and a toy policy DSL example (see policy.py changes).
 - A packaging and publishing readiness plan (AGENTS.md, READY_TO_PUBLISH).
 
 How to run locally
@@ -18,3 +19,21 @@ Hooking into packaging
 - This package is prepared for Python packaging under the name `idea164_bexproof_verifiable_best` as per the publishing requirements.
 
 Note: See AGENTS.md for architectural guidelines and how future agents should contribute.
+
+Toy policy snippet (example)
+- Simple legacy policy shape (supported by load_policy):
+  {
+    "version": 1,
+    "rules": {
+      "price_improvement_min": 0.001,
+      "latency_budget_ms": 10
+    }
+  }
+- Versioned policy blocks (new in this MVP):
+  {
+    "blocks": [
+      {"version": 1, "rules": {"price_improvement_min": 0.001, "latency_budget_ms": 10}},
+      {"version": 2, "rules": {"price_improvement_min": 0.0015, "latency_budget_ms": 8}}
+    ]
+  }
+Only the highest-version block will be applied by load_policy when blocks are present. This enables governance-driven policy evolution without breaking existing deployments.
diff --git a/bexproof/policy.py b/bexproof/policy.py
index b2aedd3..063469f 100644
--- a/bexproof/policy.py
+++ b/bexproof/policy.py
@@ -3,6 +3,11 @@
 This module provides a lightweight policy container and a tiny evaluator.
 Policies are represented as JSON-like strings for simplicity in this MVP.
 In production, replace with a proper DSL parser and validator.
+
+Enhancement: support versioned policy blocks to enable multi-version governance
+and policy evolution. The loader will select the highest-versioned block if a
+policy contains a "blocks" array. If the policy uses the legacy shape
+{"version": ..., "rules": ...}, it is still supported for backward compatibility.
 """
 from __future__ import annotations
 import json
@@ -27,9 +32,29 @@ def load_policy(policy_text: str) -> Policy:
             data = json.loads(policy_text.replace("'", '"'))
         except Exception:
             raise ValueError("Policy text is not valid JSON or Python-like dict string")
-    if not isinstance(data, dict) or "version" not in data or "rules" not in data:
-        raise ValueError("Policy must contain 'version' and 'rules' keys")
-    return Policy(version=int(data["version"]), rules=data["rules"])
+
+    # Support both legacy shape and versioned blocks:
+    # Legacy: { "version": 1, "rules": { ... } }
+    # Versioned: { "blocks": [ { "version": 1, "rules": { ... } }, ... ] }
+    if not isinstance(data, dict):
+        raise ValueError("Policy must be a JSON object")
+
+    # If versioned blocks are present, pick the highest version
+    if "blocks" in data and isinstance(data["blocks"], list):
+        blocks = data["blocks"]
+        if not blocks:
+            raise ValueError("Policy blocks list is empty")
+        # Find block with max version
+        best = max(blocks, key=lambda b: int(b.get("version", 0)))
+        if not isinstance(best, dict) or "version" not in best or "rules" not in best:
+            raise ValueError("Policy block must contain 'version' and 'rules' keys")
+        return Policy(version=int(best["version"]), rules=best["rules"])
+
+    # Legacy single-block shape
+    if "version" in data and "rules" in data:
+        return Policy(version=int(data["version"]), rules=data["rules"])
+
+    raise ValueError("Policy must contain 'version' and 'rules' keys or a 'blocks' array")
 
 
 def evaluate_policy(log: Dict[str, Any], policy: Policy) -> bool:
diff --git a/tests/test_policy_blocks.py b/tests/test_policy_blocks.py
new file mode 100644
index 0000000..5897d15
--- /dev/null
+++ b/tests/test_policy_blocks.py
@@ -0,0 +1,17 @@
+import json
+from bexproof.policy import load_policy, evaluate_policy
+
+
+def test_policy_load_with_blocks_selects_latest_version():
+    policy_text = json.dumps({
+        "blocks": [
+            {"version": 1, "rules": {"latency_budget_ms": 5}},
+            {"version": 2, "rules": {"latency_budget_ms": 3, "price_improvement_min": 0.0005}},
+        ]
+    })
+    policy = load_policy(policy_text)
+    assert policy.version == 2
+    assert policy.rules.get("latency_budget_ms") == 3
+    # Ensure evaluate_policy works with the loaded policy
+    log = {"order_id": "ORDX", "venue": "VENUEX", "latency_ms": 3, "price_improvement": 0.001}
+    assert evaluate_policy(log, policy) is True