fix: dev_mode SimpleGuard skips agent-card.json, add client.guard property

- Reorder _resolve_identity() so dev_mode (Case 3) takes priority over
  legacy agent-card.json loading (now Case 4). An A2A agent-card.json
  without public_keys no longer crashes SimpleGuard in dev_mode.
- Skip directory walking in _resolve_project_root() when dev_mode=True
- Add guard @Property on AgentIdentity for CapiscIO.connect() result

Author: beonde

capiscio_sdk/connect.py

@@ -212,6 +212,17 @@ class AgentIdentity:
     _keeper: Any = field(default=None, repr=False)
     _emitter: Any = field(default=None, repr=False)
 
+    @property
+    def guard(self) -> "SimpleGuard":
+        """Access the SimpleGuard instance for signing/verifying."""
+        if self._guard is None:
+            from .simple_guard import SimpleGuard
+            self._guard = SimpleGuard(
+                agent_id=self.did or self.agent_id,
+                base_dir=str(self.keys_dir.parent),
+            )
+        return self._guard
+    
     def emit(self, event_type: str, data: Dict[str, Any]) -> bool:
         """Emit an event to the registry."""
         if not self._emitter:

capiscio_sdk/simple_guard.py

@@ -213,13 +213,13 @@ def __exit__(self, exc_type, exc_val, exc_tb) -> None:
     def _resolve_project_root(self, base_dir: Optional[Union[str, Path]]) -> Path:
         """Resolve the project root directory.
         
-        When agent_id is provided explicitly, uses base_dir (or cwd) directly
-        without walking up the tree looking for agent-card.json.
+        When agent_id is provided explicitly or dev_mode is True, uses base_dir
+        (or cwd) directly without walking up the tree looking for agent-card.json.
         """
         current = Path(base_dir or os.getcwd()).resolve()
 
-        # When identity params are provided, don't walk looking for agent-card.json
-        if self._explicit_agent_id:
+        # When identity params are provided or in dev_mode, don't walk looking for agent-card.json
+        if self._explicit_agent_id or self.dev_mode:
             return current
 
         search_path = current
@@ -246,7 +246,16 @@ def _resolve_identity(self) -> None:
             logger.info(f"Using explicit agent_id: {self.agent_id}")
             return
 
-        # Case 3: Legacy agent-card.json (deprecated path)
+        # Case 3: Dev mode — placeholder until key generation
+        # (checked before legacy agent-card.json so dev_mode isn't
+        #  broken by an A2A agent-card.json that lacks public_keys)
+        if self.dev_mode:
+            logger.info("Dev Mode: Will generate did:key identity from keypair")
+            self.agent_id = "local-dev-agent"
+            self.signing_kid = "local-dev-key"
+            return
+        
+        # Case 4: Legacy agent-card.json (deprecated path)
         agent_card_path = self.project_root / "agent-card.json"
         if agent_card_path.exists():
             logger.warning(
@@ -269,13 +278,6 @@ def _resolve_identity(self) -> None:
             except Exception as e:
                 raise ConfigurationError(f"Failed to load agent-card.json: {e}")
             return
-            
-        # Case 4: Dev mode — placeholder until key generation
-        if self.dev_mode:
-            logger.info("Dev Mode: Will generate did:key identity from keypair")
-            self.agent_id = "local-dev-agent"
-            self.signing_kid = "local-dev-key"
-            return
 
         raise ConfigurationError(
             "No agent identity configured. Either:\n"