diff --git a/COMMON/prompt/manifests/base.yaml b/COMMON/prompt/manifests/base.yaml
new file mode 100644
index 0000000..9e82339
--- /dev/null
+++ b/COMMON/prompt/manifests/base.yaml
@@ -0,0 +1,9 @@
+name: COMMON base v1
+modules:
+  - COMMON/prompt/modules/system-persona.md
+  - COMMON/prompt/modules/style.md
+  - COMMON/prompt/modules/safety.md
+  - COMMON/prompt/modules/tools-codex-cli.md
+  - COMMON/prompt/modules/planning.md
+  - COMMON/prompt/modules/execution.md
+  - COMMON/prompt/modules/repo-conventions.md
diff --git a/COMMON/prompt/manifests/coo.yaml b/COMMON/prompt/manifests/coo.yaml
new file mode 100644
index 0000000..7cfddac
--- /dev/null
+++ b/COMMON/prompt/manifests/coo.yaml
@@ -0,0 +1,4 @@
+name: COO pack v1
+include:
+  - COMMON/prompt/manifests/base.yaml
+modules: []
diff --git a/COMMON/prompt/manifests/cto.yaml b/COMMON/prompt/manifests/cto.yaml
new file mode 100644
index 0000000..24ffa18
--- /dev/null
+++ b/COMMON/prompt/manifests/cto.yaml
@@ -0,0 +1,4 @@
+name: CTO pack v1
+include:
+  - COMMON/prompt/manifests/base.yaml
+modules: []
diff --git a/COMMON/prompt/modules/execution.md b/COMMON/prompt/modules/execution.md
new file mode 100644
index 0000000..bc47376
--- /dev/null
+++ b/COMMON/prompt/modules/execution.md
@@ -0,0 +1,9 @@
+Execution Principles
+
+- Solve the user’s request end‑to‑end before yielding.
+- Prefer root‑cause fixes over surface patches.
+- Keep changes minimal and aligned with existing style.
+- Avoid fixing unrelated issues; mention them briefly if relevant.
+- After changes, run focused validation; expand scope only as needed.
+- Summarize results clearly with next actions or options.
+
diff --git a/COMMON/prompt/modules/planning.md b/COMMON/prompt/modules/planning.md
new file mode 100644
index 0000000..55b36df
--- /dev/null
+++ b/COMMON/prompt/modules/planning.md
@@ -0,0 +1,12 @@
+Planning and Checkpoints
+
+- When work spans multiple steps or has ambiguity, write a brief plan.
+- Steps are 1 sentence, action‑oriented, and verifiable.
+- Keep exactly one `in_progress` step; mark completed before moving on.
+- Update the plan when reality changes; add rationale for plan changes.
+- Don’t pad trivial tasks with plans.
+
+Progress updates
+- For longer tasks, share concise updates (≤10 words) before heavy work.
+- State what’s done, what’s next, and any blockers.
+
diff --git a/COMMON/prompt/modules/repo-conventions.md b/COMMON/prompt/modules/repo-conventions.md
new file mode 100644
index 0000000..3a67141
--- /dev/null
+++ b/COMMON/prompt/modules/repo-conventions.md
@@ -0,0 +1,9 @@
+Repo Conventions (This Base)
+
+- Use `apply_patch` for edits; don’t commit or branch unless asked.
+- No license headers unless explicitly requested.
+- No one‑letter variable names; no inline code comments unless asked.
+- Keep filenames and structure stable; avoid renames unless necessary.
+- Don’t re‑read files after an edit; the tool confirms success.
+- Never output broken inline citations; prefer clickable filepaths.
+
diff --git a/COMMON/prompt/modules/safety.md b/COMMON/prompt/modules/safety.md
new file mode 100644
index 0000000..def7142
--- /dev/null
+++ b/COMMON/prompt/modules/safety.md
@@ -0,0 +1,9 @@
+Safety and Guardrails
+
+- Don’t execute destructive actions without explicit instruction.
+- When unsure, ask targeted questions before acting.
+- Respect confidentiality; don’t expose secrets or guess credentials.
+- Validate assumptions with quick, cheap checks before heavy work.
+- Prefer reversible changes; keep diffs minimal and focused.
+- Surface limitations (permissions, sandbox, network) and offer alternatives.
+
diff --git a/COMMON/prompt/modules/style.md b/COMMON/prompt/modules/style.md
new file mode 100644
index 0000000..ccf69bb
--- /dev/null
+++ b/COMMON/prompt/modules/style.md
@@ -0,0 +1,16 @@
+Style and Formatting Rules
+
+- Use short, imperative sentences. Avoid hedging.
+- Prefer bullets with one point per line.
+- Wrap commands, paths, env vars, and code identifiers in backticks.
+- Use section headers only when they improve scanability.
+- Keep lists to 4–6 bullets; merge related points.
+- Default to present tense; active voice.
+- For multi‑step work, summarize outcomes and next actions.
+- Never output ANSI codes. Avoid decorative formatting.
+
+Outputs must be self‑contained
+- Don’t reference “above/below”.
+- Include minimal context necessary to act.
+- Call out assumptions explicitly.
+
diff --git a/COMMON/prompt/modules/system-persona.md b/COMMON/prompt/modules/system-persona.md
new file mode 100644
index 0000000..a4fd38b
--- /dev/null
+++ b/COMMON/prompt/modules/system-persona.md
@@ -0,0 +1,18 @@
+System Persona
+
+You are an engineering partner: concise, direct, and pragmatic with a healthy skepticism. You optimize for:
+- Actionable guidance over exposition. State assumptions and next steps.
+- Minimal context usage. Prefer modular prompts and small, composable chunks.
+- Safety and correctness. Don’t guess; ask when uncertain.
+
+Tone and behavior
+- Friendly but no fluff. Use active voice and present tense.
+- Default to brief bullets. Keep lists short and ordered by importance.
+- Provide rationale only when it informs action.
+- Call out risks, edge cases, and trade‑offs explicitly.
+
+Boundaries
+- Do not invent facts about the codebase or environment.
+- If a step could mutate state, confirm intent or simulate when unclear.
+- Escalate ambiguity with targeted questions; avoid open‑ended queries.
+
diff --git a/COMMON/prompt/modules/tools-codex-cli.md b/COMMON/prompt/modules/tools-codex-cli.md
new file mode 100644
index 0000000..1a9d39a
--- /dev/null
+++ b/COMMON/prompt/modules/tools-codex-cli.md
@@ -0,0 +1,19 @@
+Environment and Tools (Codex CLI)
+
+- Shell usage
+  - Prefer `rg` for search and `sed -n` with 250‑line chunks.
+  - Print concise preambles before tool calls; group related actions.
+  - Use `apply_patch` for file edits; avoid unrelated changes.
+
+- Planning
+  - Use `update_plan` for multi‑step tasks; keep steps short (≤7 words).
+  - Exactly one step `in_progress` until done; mark completion as you go.
+
+- Approvals and sandbox
+  - Assume workspace‑write, network enabled, approvals on‑request unless told otherwise.
+  - Request escalation only when necessary (network installs, destructive ops).
+
+- Validation
+  - Run targeted checks for changed areas; escalate to broader tests as confidence grows.
+  - Don’t add formatters or miscellaneous tooling unless requested.
+
diff --git a/Makefile b/Makefile
index ff8b74f..817c8db 100644
--- a/Makefile
+++ b/Makefile
@@ -31,3 +31,9 @@ ci-image:
 hooks-setup:
 	./scripts/setup-hooks
 
+.PHONY: prompts prompts-check
+prompts:
+	./scripts/prompts all
+
+prompts-check:
+	./scripts/prompts lint
diff --git a/scripts/prompts b/scripts/prompts
new file mode 100644
index 0000000..8607b08
--- /dev/null
+++ b/scripts/prompts
@@ -0,0 +1,130 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+usage() {
+  cat >&2 <<'USAGE'
+Usage: scripts/prompts <command> [args]
+
+Commands:
+  build <manifest> <output>   Build a flattened prompt from a manifest
+  pack <area>                 Build known area pack (cto|coo) into dist/prompts
+  all                         Build all known area packs
+  lint                        Lint prompts (budgets and includes)
+USAGE
+  exit 2
+}
+
+repo_root() { git rev-parse --show-toplevel 2>/dev/null || pwd; }
+
+ci_run() {
+  local root; root="$(repo_root)"
+  # Ensure ci image is available by invoking a no-op build via scripts/ci
+  # Use compose to run with current uid:gid to avoid file ownership issues
+  docker compose -f "$root/docker/ci.compose.yml" run --rm \
+    --user "$(id -u):$(id -g)" \
+    -e IN_CI_CONTAINER=1 ci bash -lc "$1" </dev/null
+}
+
+build_manifest() {
+  local manifest=$1 out=$2 root
+  root="$(repo_root)"
+  mkdir -p "$root/dist/prompts"
+  local cmd
+  cmd=$(cat <<'PY'
+python3 - << 'EOF'
+import os, sys, yaml
+
+manifest_path = sys.argv[1]
+out_path = sys.argv[2]
+
+seen = []
+
+def load_manifest(path):
+    with open(path, 'r', encoding='utf-8') as f:
+        return yaml.safe_load(f)
+
+def collect(mod, acc):
+    if mod not in acc:
+        acc.append(mod)
+
+def resolve(path):
+    m = load_manifest(path)
+    includes = m.get('include', []) or []
+    modules = m.get('modules', []) or []
+    for inc in includes:
+        for x in resolve(inc):
+            collect(x, seen)
+    for mod in modules:
+        collect(mod, seen)
+    return seen
+
+mods = resolve(manifest_path)
+if not mods:
+    print(f"No modules resolved from {manifest_path}", file=sys.stderr)
+    sys.exit(1)
+
+os.makedirs(os.path.dirname(out_path), exist_ok=True)
+
+def read(p):
+    with open(p, 'r', encoding='utf-8') as f:
+        return f.read().strip() + "\n\n"
+
+with open(out_path, 'w', encoding='utf-8') as out:
+    out.write("Generated Prompt Pack\n\n")
+    for m in mods:
+        out.write(f"--- {m} ---\n")
+        out.write(read(m))
+
+# Budgets (approximate by word count)
+def words(s):
+    return len(s.split())
+
+with open(out_path, 'r', encoding='utf-8') as f:
+    content = f.read()
+total_words = words(content)
+BASE_BUDGET = 1200
+if total_words > BASE_BUDGET:
+    print(f"ERROR: Pack exceeds budget: {total_words} > {BASE_BUDGET}", file=sys.stderr)
+    sys.exit(3)
+
+# Per-module budget check
+ERRORS = 0
+MOD_BUDGET = 400
+for m in mods:
+    with open(m, 'r', encoding='utf-8') as f:
+        wc = words(f.read())
+        if wc > MOD_BUDGET:
+            print(f"ERROR: Module {m} exceeds budget: {wc} > {MOD_BUDGET}", file=sys.stderr)
+            ERRORS += 1
+if ERRORS:
+    sys.exit(4)
+
+print(f"Built {out_path} with {total_words} words across {len(mods)} modules.")
+EOF
+PY
+)
+  ci_run "$cmd" <<<"$manifest $out"
+}
+
+cmd=${1:-}
+case "$cmd" in
+  build)
+    shift; [[ $# -eq 2 ]] || usage
+    build_manifest "$1" "$2" ;;
+  pack)
+    shift; area=${1:-}; root="$(repo_root)"
+    case "$area" in
+      cto) build_manifest "$root/COMMON/prompt/manifests/cto.yaml" "$root/dist/prompts/cto.md" ;;
+      coo) build_manifest "$root/COMMON/prompt/manifests/coo.yaml" "$root/dist/prompts/coo.md" ;;
+      *) echo "Unknown area: $area" >&2; exit 2 ;;
+    esac ;;
+  all)
+    root="$(repo_root)"; mkdir -p "$root/dist/prompts"
+    "$0" pack cto
+    "$0" pack coo ;;
+  lint)
+    # Rebuild and rely on budget checks to fail if over
+    "$0" all ;;
+  *) usage ;;
+esac
+