Land eval-tuned combo: file handoffs, progress ledger, final-review package, REQUIRED model lines, reviewer risk budget

Validated 2026-06-10 (all gates pass): go-fractals 54.1-54.7 min / $12.81-14.31
(baseline 64.9 / $16.07); svelte-todo 55.0 min / 19.3M / $14.99 (baseline
79.7 / 27.3M / $20.98); planted-defect pass $2.77. Dispatch-model discipline
3/3 runs after moving model: into the templates as a REQUIRED line.
Full experiment log: evals docs/experiments/2026-06-10-sdd-cost-experiments.md

skills/subagent-driven-development/scripts/task-brief

@@ -0,0 +1,42 @@
+#!/usr/bin/env bash
+# Extract one task's full text from an implementation plan into a file the
+# implementer reads in one call, so the task text never has to be pasted
+# through the controller's context.
+#
+# Usage: task-brief PLAN_FILE TASK_NUMBER [OUTFILE]
+# Default OUTFILE: <git-dir>/sdd/task-<N>-brief.md — unique per repo
+# instance, so concurrent sessions cannot collide.
+set -euo pipefail
+
+if [ $# -lt 2 ] || [ $# -gt 3 ]; then
+  echo "usage: task-brief PLAN_FILE TASK_NUMBER [OUTFILE]" >&2
+  exit 2
+fi
+
+plan=$1
+n=$2
+[ -f "$plan" ] || { echo "no such plan file: $plan" >&2; exit 2; }
+
+if [ $# -eq 3 ]; then
+  out=$3
+else
+  dir=$(git rev-parse --git-path sdd)
+  mkdir -p "$dir"
+  dir=$(cd "$dir" && pwd)
+  out="$dir/task-${n}-brief.md"
+fi
+
+awk -v n="$n" '
+  /^```/ { infence = !infence }
+  !infence && /^#+[ \t]+Task[ \t]+[0-9]+/ {
+    intask = ($0 ~ ("^#+[ \t]+Task[ \t]+" n "([^0-9]|$)"))
+  }
+  intask { print }
+' "$plan" > "$out"
+
+if [ ! -s "$out" ]; then
+  echo "task ${n} not found in ${plan} (no heading matching 'Task ${n}')" >&2
+  exit 3
+fi
+
+echo "wrote ${out}: $(wc -l < "$out" | tr -d ' ') lines"