fix: clarify unavailable legacy blocker resolution

central/app/blocker_resolution.py

@@ -15,6 +15,11 @@ WORKFLOW_SCOPES = {"PRODUCT", "GROUP", "COMPANY"}
 ENTRY_FIELDS = {"scope", "scope_key", "key", "value", "reason"}
 MAX_VALUE_LENGTH = 512
 MAX_REASON_LENGTH = 2000
+MAX_COMPANY_KEY_LENGTH = 64
+
+
+class BlockerResolutionUnavailable(LookupError):
+    """The blocker exists, but has no proven installation to target safely."""
 
 
 def validate_resolution_input(payload):
@@ -87,12 +92,16 @@ def resolve_blocker_with_context(session, blocker_id, admin, payload, request_ip
             if agent.tenant_id != blocker.tenant_id:
                 raise LookupError("blocker agent tenant mismatch")
         else:
-            raise LookupError("blocker installation is required")
+            raise BlockerResolutionUnavailable(
+                "Blocker legado de empresa sem vínculo comprovado com um servidor; não é possível oferecer o reprocessamento de contexto com segurança."
+            )
 
         tenant = session.get(Tenant, blocker.tenant_id)
         company_key = _company_key(blocker, installation, tenant)
         if not company_key:
             raise ValueError("company context is unavailable")
+        if len(company_key) > MAX_COMPANY_KEY_LENGTH:
+            raise ValueError(f"company key must be at most {MAX_COMPANY_KEY_LENGTH} characters")
         if normalized["scope"] == "PRODUCT" and normalized["scope_key"] != blocker.product_code:
             raise ValueError("PRODUCT scope_key must match the blocker product code")