scripts: watchdog against runaway agents, resume instruction

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

scripts/pi-wave.sh

@@ -15,8 +15,16 @@ run() {
     cd "$wt"
     PATH="$HOME/.cargo/bin:$PATH" CARGO_TARGET_DIR="$root/target/agent-$task" \
       timeout 3000 pi -p --mode json --no-session --no-extensions --no-skills --no-themes -np --thinking low \
-      "$(cat "$root/scripts/waves/_common.md" "$1")"
-  ) >"$root/.worktrees/$task.jsonl" 2>&1
+      "$(cat "$root/scripts/waves/_common.md" "$1")" >"$root/.worktrees/$task.jsonl" 2>&1 &
+    pid=$!
+    # watchdog: a runaway agent (rate-limit retry loop) floods its log; kill it past 40 MB
+    while kill -0 "$pid" 2>/dev/null; do
+      sz=$(stat -f %z "$root/.worktrees/$task.jsonl" 2>/dev/null || echo 0)
+      [ "$sz" -gt 41943040 ] && { pkill -P "$pid"; kill "$pid"; echo RUNAWAY >>"$root/.worktrees/$task.jsonl.flag"; }
+      sleep 10
+    done
+    wait "$pid"
+  )
   rc=$?
   # final assistant text -> <task>.log; empty means the agent never answered
   python3 - "$root/.worktrees/$task.jsonl" >"$root/.worktrees/$task.log" <<'PY'

scripts/waves/_common.md

@@ -11,4 +11,6 @@ Rules, all mandatory:
 - Do NOT run git commit, git add, or touch git state. Do not run commands outside your worktree.
 - Final report (max 15 lines): what is implemented, the public API (signatures), test counts, anything skipped or any dependency you needed but did not have.
 
+If your crate already contains files from an earlier attempt, read them first, keep what is correct and finish the task; do not start over.
+
 YOUR TASK:

scripts/waves/wave2/whiteboard.md

@@ -0,0 +1,10 @@
+Crate: crates/whiteboard (notescraft-whiteboard, layer L1). SPEC section: 6 item 26 (Whiteboard bullet) and 12 (Whiteboard row). Allowed new dependencies: serde, serde_json, thiserror (`{ workspace = true }`).
+
+Implement an Excalidraw-v2-compatible model and a deterministic hand-drawn shape generator (no UI):
+1. Model: `Whiteboard { elements: Vec<Element>, app_state: serde_json::Value, files: serde_json::Value, extra: Map }`. `Element` has common fields (id, type, x, y, width, height, angle, stroke_color, background_color, fill_style, stroke_width, stroke_style, roughness, opacity, seed, version, version_nonce, is_deleted, group_ids, bound_elements, link, locked, updated) and `kind: ElementKind::{Rectangle, Diamond, Ellipse, Arrow{points,start_binding,end_binding,start_arrowhead,end_arrowhead}, Line{points}, Freedraw{points,pressures}, Text{text,font_size,font_family,text_align,vertical_align,container_id}, Image{file_id}, Frame{name}, Unknown{type_name}}`; every unknown field at every level preserved in an `extra` map and re-emitted. JSON keys are camelCase as in Excalidraw files (`strokeColor`, `isDeleted`, ...).
+2. `Whiteboard::from_str(&str)` accepting `{"type":"excalidraw","version":2,"source":..,"elements":[..],"appState":{..},"files":{..}}`; tolerant of missing optional fields; caps (32 MiB, 100000 elements); `to_string_pretty()` canonical output with `"type":"excalidraw","version":2`; `read(write(read(x))) == read(x)`.
+3. Builders: `Element::rectangle/ellipse/diamond/line/arrow/text(...)` with sensible defaults and a deterministic seed from an `IdGen` (16-char ids from a counter, no rand crate); `Whiteboard::add`, `delete` (sets isDeleted, keeps element), `bounding_box`.
+4. Hand-drawn style: `rough::outline(&Element, style: Style::{HandDrawn, Clean}) -> Vec<Polyline>` returning polylines (each `Vec<[f32;2]>`) for rectangle/diamond/ellipse/line/arrow. HandDrawn perturbs points using a seeded xorshift RNG from `element.seed` and `roughness` (double stroke, small endpoint overshoot); same seed and element give bit-identical output; Clean returns exact geometry. No NaN/inf for any input (zero size, huge sizes clamped).
+5. `Whiteboard::from_mermaid_layout` is OUT of scope (another crate does it).
+
+Tests: fixtures in tests/fixtures (hand-written Excalidraw files: all element types, bound arrow, text in container, image with files entry, unknown element type, unknown fields everywhere); round trip and preservation tests; determinism test for rough outlines; degenerate geometry (zero width, NaN input from JSON is rejected); malformed JSON returns Err.