diff --git a/AGENTS.md b/AGENTS.md
index 3abd8348a28..0fa49dbaac1 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -293,6 +293,9 @@ For one-off or infrequent operational work, start with the simplest direct end-t
 Do not build wrappers, control planes, policy layers, custom verifiers, or automation unless the direct path exposes a concrete blocker or repeated need that justifies the added machinery.
 
 Before commissioning an investigation, consult existing reports and established evidence.
+Before dispatching a ship that depends on a third-party API, prove that API can answer at the grain the product needs.
+If it cannot, stop and tell the captain.
+Do not spawn.
 Classify the deliverable:
 
 - **Ship** is the default and produces a project change through the selected delivery mode; once implementation is authorized, dispatch a ship and keep any remaining bounded research inside it unless unresolved uncertainty could materially change whether or what to build.