diff --git a/.githooks/pre-push b/.githooks/pre-push
new file mode 100755
index 0000000..a7e920f
--- /dev/null
+++ b/.githooks/pre-push
@@ -0,0 +1,6 @@
+#!/usr/bin/env bash
+# Pre-push hook — runs all check scripts before allowing a push.
+# Install with: git config core.hooksPath .githooks
+
+REPO_ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+exec "$REPO_ROOT/scripts/runChecks.sh"
diff --git a/.github/workflows/ci-global-commits-signed.yaml b/.github/workflows/ci-global-commits-signed.yaml
new file mode 100644
index 0000000..ff87103
--- /dev/null
+++ b/.github/workflows/ci-global-commits-signed.yaml
@@ -0,0 +1,56 @@
+---
+# Fails a pull request when any of its commits is not verified by GitHub.
+#
+# Uses GitHub's own commit verification (keys uploaded to each author's
+# account, plus GitHub's web-flow key for UI-made merge commits) rather than
+# running `git verify-commit` in CI, which would need every signer's key in
+# the runner's keyring. Locally, the same rule is enforced by
+# scripts/checks/verifyGitLogs.sh via the pre-push hook.
+#
+# Make this check required on `main` in the branch-protection settings so a
+# merge cannot happen while it is failing.
+name: ci-global-commits-signed
+on:
+  workflow_dispatch:
+
+  pull_request: {}
+
+permissions:
+  contents: read
+  pull-requests: read
+
+jobs:
+  verify:
+    name: all commits verified
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check every commit in the pull request
+        if: github.event_name == 'pull_request'
+        env:
+          GH_TOKEN: ${{ github.token }}
+          REPO: ${{ github.repository }}
+          PR: ${{ github.event.pull_request.number }}
+        run: |
+          set -euo pipefail
+          fail=0
+          total=0
+          while IFS=$'\t' read -r sha verified reason subject; do
+            total=$((total + 1))
+            if [ "$verified" = "true" ]; then
+              printf '  ✓ %s [%s] %s\n' "${sha:0:7}" "$reason" "$subject"
+            else
+              printf '  ✗ %s [%s] %s\n' "${sha:0:7}" "$reason" "$subject"
+              fail=$((fail + 1))
+            fi
+          done < <(gh api --paginate "repos/${REPO}/pulls/${PR}/commits" \
+            --jq '.[] | [.sha, (.commit.verification.verified|tostring), .commit.verification.reason, (.commit.message|split("\n")[0])] | @tsv')
+          echo
+          if [ "$fail" -gt 0 ]; then
+            echo "::error::${fail} of ${total} commit(s) in this pull request are not verified."
+            exit 1
+          fi
+          echo "All ${total} commit(s) are verified."
+
+      - name: Nothing to verify outside a pull request
+        if: github.event_name != 'pull_request'
+        run: echo "Manual run — this check only inspects pull request commits."
diff --git a/.yamllint.yaml b/.yamllint.yaml
new file mode 100644
index 0000000..3f2b81b
--- /dev/null
+++ b/.yamllint.yaml
@@ -0,0 +1,11 @@
+---
+# yaml-language-server: $schema=https://json.schemastore.org/yamllint.json
+extends: default
+
+rules:
+  comments: disable
+  line-length: disable
+  braces: disable
+  brackets: disable
+  truthy:
+    check-keys: false
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
new file mode 100644
index 0000000..6138f18
--- /dev/null
+++ b/CONTRIBUTING.md
@@ -0,0 +1,33 @@
+# Contributing
+
+This repo only houses the organization profile README (`profile/README.md`), but it
+follows the same conventions as the other AI Crafting repositories.
+
+## Signed commits are required
+
+Every commit must carry a valid signature. Enforced in two places:
+
+- **Locally**, by the pre-push hook. Enable it once per clone:
+
+  ```bash
+  git config core.hooksPath .githooks
+  ```
+
+  The hook runs `scripts/runChecks.sh`, which runs every executable check in
+  `scripts/checks/`: `lint.sh` (yamllint + shellcheck) and `verifyGitLogs.sh`, which
+  rejects any unpushed commit whose signature is not good (`%G?` of `G` or `U`).
+  `U` is accepted because a good signature from a key you have not personally
+  trusted is still a valid signature; GitHub's own merge commits show as `U` until
+  you trust its web-flow key.
+
+- **In CI**, by the `ci-global-commits-signed` workflow, which fails a pull request if
+  GitHub reports any of its commits as unverified. That check is required on `main`.
+
+Run the checks on demand with:
+
+```bash
+scripts/runChecks.sh
+```
+
+Code style: tabs (width 4), trailing whitespace trimmed on save except in `.md`
+files, one final newline. See `AGENTS.md`.
diff --git a/scripts/checks/lint.sh b/scripts/checks/lint.sh
new file mode 100755
index 0000000..99e5b26
--- /dev/null
+++ b/scripts/checks/lint.sh
@@ -0,0 +1,58 @@
+#!/usr/bin/env bash
+# Local pre-push lint check — mirrors the CI lint workflow.
+# Can be run from anywhere:
+#   lint.sh             — run all checks
+#   lint.sh yaml        — yamllint only
+#   lint.sh shell       — shellcheck only
+set -euo pipefail
+
+REPO_ROOT="$(cd "$(dirname "$0")/../.." && pwd)"
+cd "$REPO_ROOT"
+
+pass=0
+fail=0
+filter="${1:-all}"
+
+run_check() {
+	local name="$1"
+	shift
+	printf '\033[1m▶ %s\033[0m\n' "$name"
+	if "$@"; then
+		printf '\033[0;32m  ✓ %s passed\033[0m\n\n' "$name"
+		pass=$((pass + 1))
+	else
+		printf '\033[0;31m  ✗ %s failed\033[0m\n\n' "$name"
+		fail=$((fail + 1))
+	fi
+}
+
+should_run() {
+	[ "$filter" = "all" ] || [ "$filter" = "$1" ]
+}
+
+# yamllint (exclude node_modules)
+if should_run yaml; then
+	if command -v yamllint &>/dev/null; then
+		run_check "yamllint" bash -c \
+			'find . \( -name "*.yml" -o -name "*.yaml" \) -not -path "*/node_modules/*" -not -path "./external/*" | xargs yamllint'
+	else
+		printf '\033[0;31m  ⚠ yamllint not installed — skipping\033[0m\n\n'
+	fi
+fi
+
+# ShellCheck
+if should_run shell; then
+	if command -v shellcheck &>/dev/null; then
+		run_check "shellcheck" bash -c \
+			'find . -type f -name "*.sh" -not -path "./node_modules/*" -not -path "./external/*" -print0 | xargs -0 -r shellcheck'
+	else
+		printf '\033[0;31m  ⚠ shellcheck not installed — skipping\033[0m\n\n'
+	fi
+fi
+
+printf '\033[1m────────────────────────────\033[0m\n'
+printf '\033[0;32mPassed: %d\033[0m  \033[0;31mFailed: %d\033[0m\n' "$pass" "$fail"
+
+if [ "$fail" -gt 0 ]; then
+	exit 1
+fi
diff --git a/scripts/checks/verifyGitLogs.sh b/scripts/checks/verifyGitLogs.sh
new file mode 100755
index 0000000..3b4aa23
--- /dev/null
+++ b/scripts/checks/verifyGitLogs.sh
@@ -0,0 +1,79 @@
+#!/usr/bin/env bash
+# Verify that recent commits carry valid signatures.
+# Can be run from anywhere:
+#   verifyGitLogs.sh        — check the unpushed commits (vs the upstream),
+#                             or the last 10 if there are none / no upstream
+#   verifyGitLogs.sh N      — check the most recent N commits
+#
+# A commit passes when `git` reports its signature as good (`%G?` = G or U,
+# i.e. cryptographically valid; U = valid but the signing key isn't trusted).
+# Bad, missing, expired, revoked, or unverifiable signatures fail.
+set -euo pipefail
+
+REPO_ROOT="$(cd "$(dirname "$0")/../.." && pwd)"
+cd "$REPO_ROOT"
+
+green=$'\033[0;32m'
+red=$'\033[0;31m'
+bold=$'\033[1m'
+reset=$'\033[0m'
+
+# ---------------------------------------------------------------------------
+# Determine how many commits to verify.
+# ---------------------------------------------------------------------------
+count="${1:-}"
+
+if [ -z "$count" ]; then
+	unpushed=0
+	if upstream="$(git rev-parse --abbrev-ref --symbolic-full-name '@{upstream}' 2>/dev/null)"; then
+		unpushed="$(git rev-list --count "${upstream}..HEAD" 2>/dev/null || echo 0)"
+		echo "Upstream ${upstream}: ${unpushed} unpushed commit(s)."
+	else
+		echo "No upstream configured."
+	fi
+	if [ "$unpushed" -gt 0 ]; then
+		count="$unpushed"
+	else
+		count=10
+		echo "Falling back to the last ${count} commits."
+	fi
+fi
+
+if ! [[ "$count" =~ ^[0-9]+$ ]] || [ "$count" -eq 0 ]; then
+	echo "${red}error: commit count must be a positive integer (got '${count}')${reset}" >&2
+	exit 2
+fi
+
+# Don't ask for more commits than exist.
+total="$(git rev-list --count HEAD)"
+if [ "$count" -gt "$total" ]; then
+	count="$total"
+fi
+
+# ---------------------------------------------------------------------------
+# Verify each commit's signature.
+# ---------------------------------------------------------------------------
+printf '%s▶ Verifying signatures on the most recent %s commit(s)%s\n' "$bold" "$count" "$reset"
+
+fail=0
+while read -r sha; do
+	status="$(git show --no-patch --format='%G?' "$sha")"
+	subject="$(git show --no-patch --format='%s' "$sha")"
+	short="$(git rev-parse --short "$sha")"
+	case "$status" in
+	G | U)
+		printf '%s  ✓ %s [%s] %s%s\n' "$green" "$short" "$status" "${subject:0:60}" "$reset"
+		;;
+	*)
+		printf '%s  ✗ %s [%s] %s%s\n' "$red" "$short" "$status" "${subject:0:60}" "$reset"
+		fail=$((fail + 1))
+		;;
+	esac
+done < <(git rev-list -n "$count" HEAD)
+
+echo
+if [ "$fail" -gt 0 ]; then
+	printf '%s%d of %d commit(s) have invalid or missing signatures.%s\n' "$red" "$fail" "$count" "$reset" >&2
+	exit 1
+fi
+printf '%sAll %d commit(s) have valid signatures.%s\n' "$green" "$count" "$reset"
diff --git a/scripts/runChecks.sh b/scripts/runChecks.sh
new file mode 100755
index 0000000..018e656
--- /dev/null
+++ b/scripts/runChecks.sh
@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+# Runs all check scripts in scripts/checks/ and exits non-zero if any fail.
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "$0")/checks" && pwd)"
+fail=0
+
+for script in "$SCRIPT_DIR"/*.sh; do
+	[ -x "$script" ] || continue
+	printf '\033[1m━━━ %s ━━━\033[0m\n' "$(basename "$script")"
+	if "$script"; then
+		:
+	else
+		fail=$((fail + 1))
+	fi
+done
+
+if [ "$fail" -gt 0 ]; then
+	printf '\n\033[0;31m%d check script(s) failed.\033[0m\n' "$fail"
+	exit 1
+fi
+
+printf '\n\033[0;32mAll checks passed.\033[0m\n'