diff --git a/.project/tasks/m2-flora-fauna/README.md b/.project/tasks/m2-flora-fauna/README.md
index b996389c..b9ef5634 100644
--- a/.project/tasks/m2-flora-fauna/README.md
+++ b/.project/tasks/m2-flora-fauna/README.md
@@ -223,7 +223,7 @@ New directory: `engine/src/models/world/`
 
 ### Block 10: Sprite Generation (Proof Set)
 
-**Agent**: `godot-renderer` | **Blockers**: Blocks 1 + 3 + 4 (needs proof_species.json from 4.6)
+**Agent**: `godot-renderer` | **Blockers**: Blocks 1 + 3 + 4 (needs proof_species.json from 4.6) + `tools/sprite-generation/IN_DEVELOPMENT_DONT_USE` must not exist (sentinel file — sprite-gen pipeline is under active development while this file is present. Check with `test -f tools/sprite-generation/IN_DEVELOPMENT_DONT_USE` before any scan/generate/install. Poll periodically if blocked.)
 
 | # | Task | Description |
 |---|------|-------------|