Add selectable CASAN IDE integrations

packages/casan-harness/adapters/codex/codex_hook.py

@@ -12,11 +12,10 @@ member. Codex tool hooks are a guardrail, not a complete boundary: a turn that
 uses a hosted/specialized tool outside hook coverage is DOWNGRADED, not
 silently certified.
 
-Output contract (kept portable across Codex versions, which is why the exact
-field mapping is a Wave-3 experiment): a decision JSON on stdout AND an exit
-code — 0 = allow, 2 = block/deny — so a host that reads either signal fails
-closed the same way. Field names are accepted defensively (tool_name|tool,
-cwd|project, session_id|session) to absorb payload drift.
+Output follows Codex's current command-hook contract: turn hooks use
+`continue`/`stopReason`/`systemMessage`; PreToolUse allows with exit 0 and
+blocks with exit 2 plus `systemMessage`. Field names are accepted defensively
+(tool_name|tool, cwd|project, session_id|session) to absorb payload drift.
 """
 
 from __future__ import annotations
@@ -96,14 +95,25 @@ def handle_user_prompt_submit(payload):
         "prompt": _first(payload, "prompt", "input", "message") or "",
         "integration_mode": integration_mode(),
     })
-    if resp.get("admission_id"):
+    if resp.get("admission_id") and resp.get("decision") != "block":
         store_pointer(session, resp["admission_id"], resp.get("trace_id"))
     if resp.get("decision") == "block":
-        return _emit({"decision": "block", "reason": resp.get("reason"),
-                      "trace_id": resp.get("trace_id")}, 2)
-    return _emit({"decision": "allow", "context": resp.get("context"),
-                  "certification_strength": resp.get("certification_strength"),
-                  "warnings": resp.get("warnings", [])}, 0)
+        reason = resp.get("reason") or "policy"
+        return _emit({
+            "continue": False,
+            "stopReason": "CASAN blocked this prompt: %s" % reason,
+            "systemMessage": "CASAN trace %s denied admission" %
+                             (resp.get("trace_id") or "unknown"),
+        }, 0)
+    context = resp.get("context") or "admission open"
+    warnings = resp.get("warnings", [])
+    if warnings:
+        context += " | " + "; ".join(warnings)
+    return _emit({
+        "continue": True,
+        "systemMessage": "[CASAN] %s (strength=%s)" % (
+            context, resp.get("certification_strength") or "unknown"),
+    }, 0)
 
 
 def handle_pre_tool_use(payload):
@@ -117,16 +127,18 @@ def handle_pre_tool_use(payload):
         "project": _first(payload, "cwd", "project", "workspace"),
     })
     if resp.get("decision") == "allow":
-        return _emit({"decision": "allow", "reason": resp.get("reason")}, 0)
-    return _emit({"decision": "deny", "reason": resp.get("reason"),
-                  "trace_id": resp.get("trace_id")}, 2)
+        return _emit({}, 0)
+    return _emit({
+        "systemMessage": "CASAN denied this tool call: %s" %
+                         (resp.get("reason") or "policy"),
+    }, 2)
 
 
 def handle_post_tool_use(payload):
     session = _first(payload, "session_id", "session", "conversation_id")
     ptr = load_pointer(session)
     if not ptr:
-        return _emit({"decision": "allow", "reason": "no_admission"}, 0)
+        return _emit({}, 0)
     status = _first(payload, "status") or ("error" if _first(payload, "error", "is_error") else "success")
     bridge.op_post_tool({
         "op": "post-tool",
@@ -151,16 +163,16 @@ def handle_post_tool_use(payload):
             "cost_currency": usage.get("cost_currency"),
             "cost_source": usage.get("source"),
         })
-    return _emit({"decision": "allow"}, 0)
+    return _emit({}, 0)
 
 
 def handle_stop(payload):
     if payload.get("stop_hook_active"):
-        return _emit({"decision": "allow"}, 0)
+        return _emit({}, 0)
     session = _first(payload, "session_id", "session", "conversation_id")
     ptr = load_pointer(session)
     if not ptr:
-        return _emit({"decision": "allow", "reason": "no_admission"}, 0)
+        return _emit({}, 0)
     resp = bridge.op_finalize({
         "op": "finalize",
         "admission_id": ptr.get("admission_id"),
@@ -168,8 +180,13 @@ def handle_stop(payload):
         "assistant_summary": _first(payload, "last_assistant_message", "assistant_summary"),
     })
     clear_pointer(session)
-    return _emit({"decision": "allow", "certified": resp.get("decision") == "certified",
-                  "certification_strength": resp.get("certification_strength")}, 0)
+    return _emit({
+        "continue": True,
+        "systemMessage": "CASAN finalized trace %s (certified=%s, strength=%s)" % (
+            resp.get("trace_id") or "unknown",
+            str(resp.get("decision") == "certified").lower(),
+            resp.get("certification_strength") or "unknown"),
+    }, 0)
 
 
 HANDLERS = {
@@ -191,13 +208,14 @@ def main(argv=None):
     event = args.event or _first(payload, "hook_event_name", "event", "type")
     handler = HANDLERS.get(event)
     if handler is None:
-        return _emit({"decision": "allow", "reason": "unknown_event"}, 0)
+        return _emit({}, 0)
     try:
         return handler(payload)
     except Exception as exc:  # noqa: BLE001
         if event == "PreToolUse":
-            return _emit({"decision": "deny", "reason": "adapter_error:%s" % exc}, 2)
-        return _emit({"decision": "allow", "reason": "adapter_error:%s" % exc}, 0)
+            return _emit({"systemMessage": "CASAN adapter error: %s" % exc}, 2)
+        return _emit({"continue": True,
+                      "systemMessage": "CASAN adapter error: %s" % exc}, 0)
 
 
 if __name__ == "__main__":