diff --git a/.gitignore b/.gitignore
index 7917355..75f4e44 100644
--- a/.gitignore
+++ b/.gitignore
@@ -33,6 +33,12 @@ yarn-error.log*
 .pnpm-store/
 .tmp/
 
+# Local tool state: CodeGraph index, IDE, agent tooling. They are not gate
+# inputs, and their churn would otherwise invalidate the pre-commit stamp.
+.codegraph/
+.idea/
+.zcode/
+
 # Environment variables
 .env
 .env.local
diff --git a/.husky/pre-commit b/.husky/pre-commit
index 98475b5..6c60fd7 100644
--- a/.husky/pre-commit
+++ b/.husky/pre-commit
@@ -1 +1 @@
-pnpm test
+pnpm run check
diff --git a/AGENTS.md b/AGENTS.md
index f8ab1b9..d4b043e 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -42,10 +42,8 @@ Complete ALL of these before ANY commit:
 - Review the full diff independently: every change necessary, correct, and not over-engineered.
 - Clean up generated temporary files and temporary or unhelpful comments.
 - Load the [code-review](https://github.com/mattpocock/skills/tree/main/skills/engineering/code-review) skill if available, run it to review all the changes, and independently verify or follow each of its suggestions when its multi-axis analysis done.
-- Run the following commands concurrently for maximum efficiency
-  - First, run `pnpm run lint` to fix all lint errors.
-  - Second, run `pnpm run typecheck` to fix all type errors.
-  - Third, run `pnpm run coverage` to run and ensure 100% per-file coverage. Please capture the ALL content of the full output without truncation or tailing.
+- Run `pnpm run check`: it runs `pnpm run lint`, `pnpm run typecheck` and `pnpm run coverage` concurrently, prints each tool's COMPLETE output, and fails when any of them does (the same logs stay in `.tmp/check-logs/`).
+  - Fix every lint and type error, and ensure 100% per-file coverage. Please capture the ALL content of the full output without truncation or tailing.
     - Example for per-file 100% coverage output:
       ```
       % Coverage report from v8
@@ -54,6 +52,7 @@ Complete ALL of these before ANY commit:
       -------------------------|---------|----------|---------|---------|-------------------
       -------------------------|---------|----------|---------|---------|-------------------
       ```
+  - The `pre-commit` hook runs this same gate, and a green run stamps the worktree into `.tmp/check.stamp`, so a commit of unchanged content skips it; `pnpm run check --full` forces a full re-run.
 
 ## Layout & responsive
 
diff --git a/package.json b/package.json
index f855151..cd2990c 100644
--- a/package.json
+++ b/package.json
@@ -41,6 +41,7 @@
     "build": "tsdown",
     "lint": "oxlint",
     "lint:fix": "oxlint --fix",
+    "check": "bash scripts/check.sh",
     "watch": "bash scripts/watch.sh",
     "web": "bash scripts/web.sh",
     "register": "bash scripts/register.sh",
diff --git a/scripts/check.sh b/scripts/check.sh
new file mode 100755
index 0000000..841114a
--- /dev/null
+++ b/scripts/check.sh
@@ -0,0 +1,83 @@
+#!/usr/bin/env bash
+# The pre-commit gate: lint, typecheck and the full coverage suite, run
+# concurrently, each tool's complete output kept in .tmp/check-logs.
+#
+# A green run fingerprints the worktree into .tmp/check.stamp, so the husky
+# hook skips the full suite for content that just passed. Any tracked or
+# untracked edit invalidates the stamp, and so does a stamp older than an hour:
+# gitignored inputs (lib/, node_modules, staged dsh baselines) can drift without
+# changing the fingerprint. `--full` always re-runs.
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+cd "$ROOT"
+
+STAMP=".tmp/check.stamp"
+LOGS=".tmp/check-logs"
+INDEX=".tmp/check-index"
+STAMP_TTL_MIN=60
+
+# The fingerprint is the worktree's tree object, built through a THROWAWAY
+# index: staged and unstaged edits plus untracked files all count, while
+# gitignored outputs (.tmp, coverage, lib, node_modules, IDE/tool state) do not.
+fingerprint() {
+  local tree
+  mkdir -p .tmp
+  rm -f "$INDEX"
+  if ! GIT_INDEX_FILE="$INDEX" git add -A -- . >/dev/null; then
+    rm -f "$INDEX"
+    return 1
+  fi
+  tree="$(GIT_INDEX_FILE="$INDEX" git write-tree)" || tree=""
+  rm -f "$INDEX"
+  [[ -n "$tree" ]] || return 1
+  printf '%s\n' "$tree"
+}
+
+FULL=0
+[[ "${1:-}" == "--full" ]] && FULL=1
+
+# Command substitutions do not inherit errexit on bash 3.2 (macOS), so both
+# fingerprint calls check their status explicitly.
+BEFORE="$(fingerprint)" || { echo "==> check: cannot fingerprint the worktree" >&2; exit 1; }
+if (( FULL == 0 )) && [[ -f "$STAMP" ]] && [[ "$(cat "$STAMP")" == "$BEFORE" ]] \
+  && [[ -n "$(find "$STAMP" -mmin "-$STAMP_TTL_MIN" 2>/dev/null)" ]]; then
+  echo "==> check: worktree unchanged since the last green gate — skipping. Run 'pnpm run check --full' to force a full run."
+  exit 0
+fi
+
+rm -rf "$LOGS"
+mkdir -p "$LOGS"
+
+echo "==> check: lint, typecheck and coverage in parallel"
+pnpm run lint >"$LOGS/lint.log" 2>&1 & LINT=$!
+pnpm run typecheck >"$LOGS/typecheck.log" 2>&1 & TYPECHECK=$!
+pnpm run coverage >"$LOGS/coverage.log" 2>&1 & COVERAGE=$!
+
+FAILED=""
+wait "$LINT" || FAILED="$FAILED lint"
+wait "$TYPECHECK" || FAILED="$FAILED typecheck"
+wait "$COVERAGE" || FAILED="$FAILED coverage"
+
+for name in lint typecheck coverage; do
+  echo
+  echo "===== $name ====="
+  cat "$LOGS/$name.log"
+done
+
+echo
+if [[ -n "$FAILED" ]]; then
+  echo "==> check FAILED:$FAILED" >&2
+  exit 1
+fi
+
+# A gate run over a moving worktree proves nothing, so an edit during the run
+# must not be stamped as verified.
+AFTER="$(fingerprint)" || { echo "==> check: cannot fingerprint the worktree" >&2; exit 1; }
+if [[ "$BEFORE" != "$AFTER" ]]; then
+  echo "==> check: the worktree changed while the gate ran — re-run before committing." >&2
+  exit 1
+fi
+
+printf '%s\n' "$BEFORE" > "$STAMP"
+echo "==> check passed: lint, typecheck and 100% per-file coverage (lint/typecheck/coverage output above; logs in $LOGS)"