diff --git a/navi/profiles/modeler_3d/config.json b/navi/profiles/modeler_3d/config.json
index 568aeeb..fcce046 100644
--- a/navi/profiles/modeler_3d/config.json
+++ b/navi/profiles/modeler_3d/config.json
@@ -31,6 +31,7 @@
   "adaptive_replan_enabled": true,
   "subagent_planning_enabled": false,
   "subagent_tools": [
+    "scratchpad",
     "filesystem",
     "scad_lint"
   ],
diff --git a/navi/profiles/modeler_3d/subagent_system_prompt.txt b/navi/profiles/modeler_3d/subagent_system_prompt.txt
index 73bf45a..f4ef89b 100644
--- a/navi/profiles/modeler_3d/subagent_system_prompt.txt
+++ b/navi/profiles/modeler_3d/subagent_system_prompt.txt
@@ -4,13 +4,14 @@
 
 - Treat the briefing as the source of truth. Do not infer missing functional dimensions unless the briefing explicitly says to use defaults.
 - Write clean production OpenSCAD to the exact `.scad` path requested in the briefing.
+- Your runtime session id may be an ephemeral `subagent_*` id. Do not derive output paths from it. Use the exact parent session directory and target filename from the briefing.
 - Use only OpenSCAD source and the available tools. Do not use Python/CadQuery/trimesh/raw mesh scripts to generate the model.
 - Keep the source parametric: named dimensions, clear modules, robust boolean overlaps, and no abandoned modules.
 - Do not include prose, self-correction notes, drafts, "let's", "actually", commented-out failed attempts, or conversation transcript inside the `.scad` file.
 - After writing or editing the file, run `scad_lint` on the `.scad` path and fix lint errors you can address locally.
 - Do not publish artifacts. Do not compile/render unless the briefing explicitly asks for it.
-- Use at most two tool-call iterations for normal authoring: first `filesystem write`, then `scad_lint`. After lint succeeds or reports only non-blocking warnings, stop calling tools and return the final response immediately.
-- Do not use scratchpad, todo, planning notes, progress tracking, or internal status tools. If those tools are unavailable, that is intentional.
+- You may use `scratchpad` to read transferred design context or write a short design note when the briefing is dense. Do not use scratchpad for progress tracking or as a substitute for writing the `.scad` file.
+- After lint succeeds or reports only non-blocking warnings, stop calling tools and return the final response.
 
 Final response format for OpenSCAD authoring:
 
diff --git a/navi/profiles/modeler_3d/system_prompt.txt b/navi/profiles/modeler_3d/system_prompt.txt
index 114da13..d9f2ce4 100644
--- a/navi/profiles/modeler_3d/system_prompt.txt
+++ b/navi/profiles/modeler_3d/system_prompt.txt
@@ -114,7 +114,7 @@
 - required source comments contract;
 - instruction to write clean production OpenSCAD only, with no prose, self-correction notes, abandoned modules, or commented-out failed attempts;
 - instruction to call `filesystem write` for the `.scad` file and then `scad_lint`;
-- `max_iterations` set to 6, because authoring should normally need only write, lint, optional fix, and final response;
+- `max_iterations` set to 40, so the subagent has enough room to reason, write, lint, and repair without premature cutoff;
 - expected final output: the `.scad` path, lint result, and concise notes about implemented parameters.
 
 The subagent must not publish the artifact and should not compile/render unless the main brief explicitly asks for it. The main agent must run final `scad_lint`, `model_3d`, `render_3d`, and `image_view` after the subagent returns.