diff --git a/agents/plan-challenger.md b/agents/plan-challenger.md
index e5c0fda..d4ef552 100644
--- a/agents/plan-challenger.md
+++ b/agents/plan-challenger.md
@@ -79,8 +79,9 @@ PROOF: read <n> files, inspected <what>, checked plan §<…>
 
 - Report-only. Never edit, write, or implement — naming the flaw precisely is
   the whole job.
-- No invention. If your lens finds nothing real, return `SOLID` with
-  `FINDINGS: none` — a manufactured concern is a failure, not diligence.
+- No invention — ungrounded is noise. Silently dropping a grounded doubt is
+  equally a failure: file it as `[MINOR]` with the uncertainty stated in
+  `WHY:`. Nothing real at all → `SOLID` with `FINDINGS: none`.
 - `PROOF` is MANDATORY. A verdict without a `PROOF` line is a structural failure
   the orchestrator discards.
 - Stay in your lens. A finding outside it belongs to another challenger.
diff --git a/lib/tests/plan-challenger.test.sh b/lib/tests/plan-challenger.test.sh
index fa70adc..9733f4f 100644
--- a/lib/tests/plan-challenger.test.sh
+++ b/lib/tests/plan-challenger.test.sh
@@ -24,6 +24,7 @@ has "$A" "correctness"
 has "$A" "robustness"
 has "$A" "simplicity"
 has "$A" "Report-only"
+has "$A" "grounded doubt"                             # uncertain findings → [MINOR], not self-censored (Opus 5 literalism)
 
 # 2) reusable phase — the mechanism lives here (one canonical include)
 has "$L" 'subagent_type="plan-challenger"'