diff --git a/.gitea/workflows/check.yml b/.gitea/workflows/check.yml
index 258c39d..0ec8d22 100644
--- a/.gitea/workflows/check.yml
+++ b/.gitea/workflows/check.yml
@@ -8,7 +8,10 @@ jobs:
   check:
     runs-on: ubuntu-latest
     steps:
+      # gitleaks reads the commit history, so a shallow clone would hide it.
       - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
       - uses: actions/setup-python@v5
         with:
           python-version: "3.12"
diff --git a/.gitleaks-baseline.json b/.gitleaks-baseline.json
new file mode 100644
index 0000000..67f0f4c
--- /dev/null
+++ b/.gitleaks-baseline.json
@@ -0,0 +1,282 @@
+[
+ {
+  "RuleID": "generic-api-key",
+  "Description": "Detected a Generic API Key, potentially exposing access to various services and sensitive operations.",
+  "StartLine": 82,
+  "EndLine": 82,
+  "StartColumn": 2,
+  "EndColumn": 52,
+  "Match": "yamtrack_secret: \"REDACTED\"",
+  "Secret": "REDACTED",
+  "File": "yamtrack/vars/default.yml",
+  "SymlinkFile": "",
+  "Commit": "af2e7394b8b2882b0a1f3cf74976dc1fafd610d0",
+  "Entropy": 3.8042293,
+  "Author": "Amritanshu",
+  "Email": "git@tanshu.com",
+  "Date": "2026-10-18T16:05:53Z",
+  "Message": "Add the Yamtrack playbook",
+  "Tags": [],
+  "Fingerprint": "af2e7394b8b2882b0a1f3cf74976dc1fafd610d0:yamtrack/vars/default.yml:generic-api-key:82"
+ },
+ {
+  "RuleID": "generic-api-key",
+  "Description": "Detected a Generic API Key, potentially exposing access to various services and sensitive operations.",
+  "StartLine": 86,
+  "EndLine": 86,
+  "StartColumn": 2,
+  "EndColumn": 40,
+  "Match": "auth_secret: \"REDACTED\"",
+  "Secret": "REDACTED",
+  "File": "sms-wa-bridge/vars/default.yml",
+  "SymlinkFile": "",
+  "Commit": "26a0654fea2b85cfcc1587418834f2358f384ae9",
+  "Entropy": 3.6572683,
+  "Author": "Amritanshu",
+  "Email": "git@tanshu.com",
+  "Date": "2026-10-18T16:05:53Z",
+  "Message": "Add the sms-wa-bridge playbook",
+  "Tags": [],
+  "Fingerprint": "26a0654fea2b85cfcc1587418834f2358f384ae9:sms-wa-bridge/vars/default.yml:generic-api-key:86"
+ },
+ {
+  "RuleID": "generic-api-key",
+  "Description": "Detected a Generic API Key, potentially exposing access to various services and sensitive operations.",
+  "StartLine": 17,
+  "EndLine": 17,
+  "StartColumn": 2,
+  "EndColumn": 77,
+  "Match": "secret_key: REDACTED",
+  "Secret": "REDACTED",
+  "File": "outline/vars/default.yml",
+  "SymlinkFile": "",
+  "Commit": "250456e3fe1ca58fa836fe182c0519327bba898c",
+  "Entropy": 3.7609768,
+  "Author": "Amritanshu",
+  "Email": "git@tanshu.com",
+  "Date": "2026-10-18T16:05:52Z",
+  "Message": "Add the Outline playbook",
+  "Tags": [],
+  "Fingerprint": "250456e3fe1ca58fa836fe182c0519327bba898c:outline/vars/default.yml:generic-api-key:17"
+ },
+ {
+  "RuleID": "generic-api-key",
+  "Description": "Detected a Generic API Key, potentially exposing access to various services and sensitive operations.",
+  "StartLine": 18,
+  "EndLine": 18,
+  "StartColumn": 2,
+  "EndColumn": 79,
+  "Match": "utils_secret: REDACTED",
+  "Secret": "REDACTED",
+  "File": "outline/vars/default.yml",
+  "SymlinkFile": "",
+  "Commit": "250456e3fe1ca58fa836fe182c0519327bba898c",
+  "Entropy": 3.9114883,
+  "Author": "Amritanshu",
+  "Email": "git@tanshu.com",
+  "Date": "2026-10-18T16:05:52Z",
+  "Message": "Add the Outline playbook",
+  "Tags": [],
+  "Fingerprint": "250456e3fe1ca58fa836fe182c0519327bba898c:outline/vars/default.yml:generic-api-key:18"
+ },
+ {
+  "RuleID": "generic-api-key",
+  "Description": "Detected a Generic API Key, potentially exposing access to various services and sensitive operations.",
+  "StartLine": 9,
+  "EndLine": 9,
+  "StartColumn": 2,
+  "EndColumn": 75,
+  "Match": "password: REDACTED",
+  "Secret": "REDACTED",
+  "File": "registry/vars/default.yml",
+  "SymlinkFile": "",
+  "Commit": "f04a29b5c7050fa4404e9fc94e3489211c9dff50",
+  "Entropy": 3.8824525,
+  "Author": "Amritanshu",
+  "Email": "git@tanshu.com",
+  "Date": "2024-12-17T12:23:30Z",
+  "Message": "Docker registry",
+  "Tags": [],
+  "Fingerprint": "f04a29b5c7050fa4404e9fc94e3489211c9dff50:registry/vars/default.yml:generic-api-key:9"
+ },
+ {
+  "RuleID": "generic-api-key",
+  "Description": "Detected a Generic API Key, potentially exposing access to various services and sensitive operations.",
+  "StartLine": 394,
+  "EndLine": 394,
+  "StartColumn": 8,
+  "EndColumn": 40,
+  "Match": "X-Auth: REDACTED'",
+  "Secret": "REDACTED",
+  "File": "sms-wa-bridge/readme.md",
+  "SymlinkFile": "",
+  "Commit": "26a0654fea2b85cfcc1587418834f2358f384ae9",
+  "Entropy": 3.6572683,
+  "Author": "Amritanshu",
+  "Email": "git@tanshu.com",
+  "Date": "2026-10-18T16:05:53Z",
+  "Message": "Add the sms-wa-bridge playbook",
+  "Tags": [],
+  "Fingerprint": "26a0654fea2b85cfcc1587418834f2358f384ae9:sms-wa-bridge/readme.md:generic-api-key:394"
+ },
+ {
+  "RuleID": "generic-api-key",
+  "Description": "Detected a Generic API Key, potentially exposing access to various services and sensitive operations.",
+  "StartLine": 408,
+  "EndLine": 408,
+  "StartColumn": 48,
+  "EndColumn": 80,
+  "Match": "X-Auth: REDACTED`",
+  "Secret": "REDACTED",
+  "File": "sms-wa-bridge/readme.md",
+  "SymlinkFile": "",
+  "Commit": "26a0654fea2b85cfcc1587418834f2358f384ae9",
+  "Entropy": 3.6572683,
+  "Author": "Amritanshu",
+  "Email": "git@tanshu.com",
+  "Date": "2026-10-18T16:05:53Z",
+  "Message": "Add the sms-wa-bridge playbook",
+  "Tags": [],
+  "Fingerprint": "26a0654fea2b85cfcc1587418834f2358f384ae9:sms-wa-bridge/readme.md:generic-api-key:408"
+ },
+ {
+  "RuleID": "generic-api-key",
+  "Description": "Detected a Generic API Key, potentially exposing access to various services and sensitive operations.",
+  "StartLine": 2,
+  "EndLine": 2,
+  "StartColumn": 2,
+  "EndColumn": 75,
+  "Match": "API_TOKEN=REDACTED",
+  "Secret": "REDACTED",
+  "File": "bifrost/app/.env",
+  "SymlinkFile": "",
+  "Commit": "02cc1dafe599f7ceeba7ad79669568aa83970ccc",
+  "Entropy": 3.589582,
+  "Author": "tanshu",
+  "Email": "tanshu@gmail.com",
+  "Date": "2020-05-04T11:34:09Z",
+  "Message": "Bifrost deployed using ansible",
+  "Tags": [],
+  "Fingerprint": "02cc1dafe599f7ceeba7ad79669568aa83970ccc:bifrost/app/.env:generic-api-key:2"
+ },
+ {
+  "RuleID": "generic-api-key",
+  "Description": "Detected a Generic API Key, potentially exposing access to various services and sensitive operations.",
+  "StartLine": 13,
+  "EndLine": 13,
+  "StartColumn": 2,
+  "EndColumn": 76,
+  "Match": "SECRET_KEY=REDACTED",
+  "Secret": "REDACTED",
+  "File": "brewman/files/.env-exp",
+  "SymlinkFile": "",
+  "Commit": "ed8feff302e70deb575295a15b81b74bb89b8e6e",
+  "Entropy": 3.8843737,
+  "Author": "tanshu",
+  "Email": "git@tanshu.com",
+  "Date": "2020-10-17T06:57:59Z",
+  "Message": "New: Fastapi Brewman Fastapi Barker",
+  "Tags": [],
+  "Fingerprint": "ed8feff302e70deb575295a15b81b74bb89b8e6e:brewman/files/.env-exp:generic-api-key:13"
+ },
+ {
+  "RuleID": "generic-api-key",
+  "Description": "Detected a Generic API Key, potentially exposing access to various services and sensitive operations.",
+  "StartLine": 13,
+  "EndLine": 13,
+  "StartColumn": 2,
+  "EndColumn": 76,
+  "Match": "SECRET_KEY=REDACTED",
+  "Secret": "REDACTED",
+  "File": "brewman/files/.env-acc",
+  "SymlinkFile": "",
+  "Commit": "ed8feff302e70deb575295a15b81b74bb89b8e6e",
+  "Entropy": 3.887898,
+  "Author": "tanshu",
+  "Email": "git@tanshu.com",
+  "Date": "2020-10-17T06:57:59Z",
+  "Message": "New: Fastapi Brewman Fastapi Barker",
+  "Tags": [],
+  "Fingerprint": "ed8feff302e70deb575295a15b81b74bb89b8e6e:brewman/files/.env-acc:generic-api-key:13"
+ },
+ {
+  "RuleID": "generic-api-key",
+  "Description": "Detected a Generic API Key, potentially exposing access to various services and sensitive operations.",
+  "StartLine": 13,
+  "EndLine": 13,
+  "StartColumn": 2,
+  "EndColumn": 76,
+  "Match": "SECRET_KEY=REDACTED",
+  "Secret": "REDACTED",
+  "File": "brewman/files/.env-mhl",
+  "SymlinkFile": "",
+  "Commit": "ed8feff302e70deb575295a15b81b74bb89b8e6e",
+  "Entropy": 3.8439462,
+  "Author": "tanshu",
+  "Email": "git@tanshu.com",
+  "Date": "2020-10-17T06:57:59Z",
+  "Message": "New: Fastapi Brewman Fastapi Barker",
+  "Tags": [],
+  "Fingerprint": "ed8feff302e70deb575295a15b81b74bb89b8e6e:brewman/files/.env-mhl:generic-api-key:13"
+ },
+ {
+  "RuleID": "generic-api-key",
+  "Description": "Detected a Generic API Key, potentially exposing access to various services and sensitive operations.",
+  "StartLine": 8,
+  "EndLine": 8,
+  "StartColumn": 2,
+  "EndColumn": 76,
+  "Match": "SECRET_KEY=REDACTED",
+  "Secret": "REDACTED",
+  "File": "barker/files/.env",
+  "SymlinkFile": "",
+  "Commit": "ed8feff302e70deb575295a15b81b74bb89b8e6e",
+  "Entropy": 3.8627045,
+  "Author": "tanshu",
+  "Email": "git@tanshu.com",
+  "Date": "2020-10-17T06:57:59Z",
+  "Message": "New: Fastapi Brewman Fastapi Barker",
+  "Tags": [],
+  "Fingerprint": "ed8feff302e70deb575295a15b81b74bb89b8e6e:barker/files/.env:generic-api-key:8"
+ },
+ {
+  "RuleID": "generic-api-key",
+  "Description": "Detected a Generic API Key, potentially exposing access to various services and sensitive operations.",
+  "StartLine": 13,
+  "EndLine": 13,
+  "StartColumn": 2,
+  "EndColumn": 76,
+  "Match": "SECRET_KEY=REDACTED",
+  "Secret": "REDACTED",
+  "File": "brewman/files/.env-hops",
+  "SymlinkFile": "",
+  "Commit": "ed8feff302e70deb575295a15b81b74bb89b8e6e",
+  "Entropy": 3.8454638,
+  "Author": "tanshu",
+  "Email": "git@tanshu.com",
+  "Date": "2020-10-17T06:57:59Z",
+  "Message": "New: Fastapi Brewman Fastapi Barker",
+  "Tags": [],
+  "Fingerprint": "ed8feff302e70deb575295a15b81b74bb89b8e6e:brewman/files/.env-hops:generic-api-key:13"
+ },
+ {
+  "RuleID": "generic-api-key",
+  "Description": "Detected a Generic API Key, potentially exposing access to various services and sensitive operations.",
+  "StartLine": 2,
+  "EndLine": 2,
+  "StartColumn": 2,
+  "EndColumn": 81,
+  "Match": "SECRET_KEY_BASE=REDACTED",
+  "Secret": "REDACTED",
+  "File": "snibox/files/.env",
+  "SymlinkFile": "",
+  "Commit": "5922227712b37dfd0e67df2a2b5334998d1f2702",
+  "Entropy": 3.8725784,
+  "Author": "tanshu",
+  "Email": "git@tanshu.com",
+  "Date": "2020-10-17T06:58:52Z",
+  "Message": "New: Snibox",
+  "Tags": [],
+  "Fingerprint": "5922227712b37dfd0e67df2a2b5334998d1f2702:snibox/files/.env:generic-api-key:2"
+ }
+]
diff --git a/.gitleaks.toml b/.gitleaks.toml
new file mode 100644
index 0000000..883da45
--- /dev/null
+++ b/.gitleaks.toml
@@ -0,0 +1,10 @@
+[extend]
+useDefault = true
+
+[allowlist]
+description = "Caches and vendored collections are not repo content"
+paths = [
+  '''\.ansible/''',
+  '''\.scratch/''',
+  '''\.gitleaks-baseline\.json''',
+]
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 76fa5ce..a5fac49 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -1,6 +1,7 @@
 ---
-# Local hook, same checks as CI. Enable with:
+# Local hooks, same checks as CI. Enable with:
 #   pre-commit install
+#   pre-commit install --hook-type commit-msg
 repos:
   - repo: https://github.com/pre-commit/pre-commit-hooks
     rev: v4.6.0
@@ -18,3 +19,15 @@ repos:
     rev: v24.7.0
     hooks:
       - id: ansible-lint
+  - repo: local
+    hooks:
+      - id: gitleaks
+        name: gitleaks
+        entry: scripts/check-secrets.sh --staged
+        language: script
+        pass_filenames: false
+      - id: commit-message
+        name: commit message
+        entry: scripts/check-commit-msg.sh
+        language: script
+        stages: [commit-msg]
diff --git a/AGENTS.md b/AGENTS.md
index 48f0691..62b1c07 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -3,14 +3,18 @@
 This repository holds one Ansible playbook per service. Read
 [CODING_STANDARDS.md](CODING_STANDARDS.md) before adding or changing a playbook.
 
-- Layout and naming: [CODING_STANDARDS.md](CODING_STANDARDS.md).
-- Checks: run `./scripts/check.sh`. It runs yamllint, ansible-lint, and a syntax
-  check on every `*/playbook.yml`. CI runs the same script.
+- Checks: run `./scripts/check.sh`. Add `--changed` while iterating to lint only
+  the YAML files that differ from HEAD. CI runs the full script.
 - Review baseline: `origin/main`. The review diff is `git diff origin/main...HEAD`.
 - Migration spec: [docs/podman-migration.md](docs/podman-migration.md). Section 8
   lists the repo changes the migration expects.
 - Issue tracker: [docs/agents/issue-tracker.md](docs/agents/issue-tracker.md).
 - Scratch files: write them under `.scratch/`. It is git-ignored, and `/tmp` is
   wiped between tool calls in this environment.
-- Secrets: `vars/default.yml` holds deploy values, including passwords. Do not
-  copy a production value into a file you push to a public remote.
+- Read-only `$HOME`: if `$HOME` is read-only, point `XDG_CACHE_HOME`,
+  `UV_CACHE_DIR`, `PIP_CACHE_DIR`, and `ANSIBLE_HOME` under `.scratch/`. The check
+  script already does this, and a vault password file has to live there too.
+- Secrets: `vars/default.yml` holds deploy values, including passwords. gitleaks
+  runs before each commit and in CI. Known values are in
+  [.gitleaks-baseline.json](.gitleaks-baseline.json); rotate or vault a value
+  instead of adding a new entry.
diff --git a/scripts/check-commit-msg.sh b/scripts/check-commit-msg.sh
new file mode 100755
index 0000000..299227f
--- /dev/null
+++ b/scripts/check-commit-msg.sh
@@ -0,0 +1,20 @@
+#!/usr/bin/env bash
+# Reject placeholder commit subjects. pre-commit passes the message file.
+set -euo pipefail
+
+message_file="$1"
+subject=$(head -n 1 "$message_file")
+
+if [ -z "${subject//[[:space:]]/}" ]; then
+  echo "commit subject is empty" >&2
+  exit 1
+fi
+
+case "${subject,,}" in
+  misc|misc.|wip|wip.|update|updates|fix|fixes|change|changes|stuff|temp|tmp)
+    echo "commit subject is a placeholder: '$subject'" >&2
+    exit 1
+    ;;
+esac
+
+exit 0
diff --git a/scripts/check-secrets.sh b/scripts/check-secrets.sh
new file mode 100755
index 0000000..30745fc
--- /dev/null
+++ b/scripts/check-secrets.sh
@@ -0,0 +1,35 @@
+#!/usr/bin/env bash
+# Scan for secrets. Known values are listed in the redacted baseline.
+# Usage: scripts/check-secrets.sh [--staged]
+set -euo pipefail
+
+cd "$(dirname "${BASH_SOURCE[0]}")/.."
+
+version="8.30.1"
+bin="$PWD/.scratch/bin/gitleaks"
+
+if ! command -v gitleaks >/dev/null 2>&1; then
+  if [ ! -x "$bin" ]; then
+    case "$(uname -m)" in
+      x86_64|amd64) arch=x64 ;;
+      aarch64|arm64) arch=arm64 ;;
+      *)
+        echo "unsupported architecture: $(uname -m)" >&2
+        exit 1
+        ;;
+    esac
+    echo "installing gitleaks $version into .scratch/bin" >&2
+    mkdir -p .scratch/bin
+    curl -fsSL -o .scratch/bin/gitleaks.tar.gz \
+      "https://github.com/gitleaks/gitleaks/releases/download/v${version}/gitleaks_${version}_linux_${arch}.tar.gz"
+    tar -xzf .scratch/bin/gitleaks.tar.gz -C .scratch/bin gitleaks
+  fi
+  PATH="$PWD/.scratch/bin:$PATH"
+fi
+
+if [ "${1:-}" = "--staged" ]; then
+  gitleaks git --pre-commit --staged --redact --verbose \
+    --baseline-path .gitleaks-baseline.json
+else
+  gitleaks git --baseline-path .gitleaks-baseline.json --redact --no-banner
+fi
diff --git a/scripts/check.sh b/scripts/check.sh
index 1749d3d..4947eab 100755
--- a/scripts/check.sh
+++ b/scripts/check.sh
@@ -1,18 +1,35 @@
 #!/usr/bin/env bash
 # Run every check this repo has. CI and pre-commit call the same script.
+# Usage: scripts/check.sh [--changed]
 set -euo pipefail
+shopt -s nullglob
 
 cd "$(dirname "${BASH_SOURCE[0]}")/.."
 
-# Ansible and uv both want a writable cache. Keep them in the checkout so the
-# script works when $HOME is read-only, which is the case in the agent sandbox.
+changed=0
+for arg in "$@"; do
+  case "$arg" in
+    --changed) changed=1 ;;
+    *)
+      echo "unknown argument: $arg" >&2
+      echo "usage: scripts/check.sh [--changed]" >&2
+      exit 2
+      ;;
+  esac
+done
+
+# Ansible and uv want writable caches. Keep them in the checkout so the script
+# works when $HOME is read-only, which is the case in the agent sandbox.
 export ANSIBLE_CONFIG="${ANSIBLE_CONFIG:-$PWD/ansible.cfg}"
 export ANSIBLE_HOME="${ANSIBLE_HOME:-$PWD/.ansible/home}"
 export ANSIBLE_LOCAL_TEMP="${ANSIBLE_LOCAL_TEMP:-$PWD/.ansible/tmp}"
+export ANSIBLE_GALAXY_CACHE_DIR="${ANSIBLE_GALAXY_CACHE_DIR:-$PWD/.ansible/galaxy_cache}"
 export UV_CACHE_DIR="${UV_CACHE_DIR:-$PWD/.ansible/uv-cache}"
 export UV_TOOL_DIR="${UV_TOOL_DIR:-$PWD/.ansible/uv-tools}"
-export ANSIBLE_GALAXY_CACHE_DIR="${ANSIBLE_GALAXY_CACHE_DIR:-$PWD/.ansible/galaxy_cache}"
-mkdir -p "$ANSIBLE_LOCAL_TEMP" "$UV_CACHE_DIR" "$UV_TOOL_DIR" "$ANSIBLE_GALAXY_CACHE_DIR" "$ANSIBLE_HOME"
+export XDG_CACHE_HOME="${XDG_CACHE_HOME:-$PWD/.scratch/cache}"
+export PIP_CACHE_DIR="${PIP_CACHE_DIR:-$PWD/.scratch/cache/pip}"
+mkdir -p "$ANSIBLE_LOCAL_TEMP" "$UV_CACHE_DIR" "$UV_TOOL_DIR" \
+  "$ANSIBLE_GALAXY_CACHE_DIR" "$ANSIBLE_HOME" "$XDG_CACHE_HOME" "$PIP_CACHE_DIR"
 
 if [ -f requirements.yml ]; then
   echo "== ansible-galaxy collection install =="
@@ -29,15 +46,90 @@ run() {
   fi
 }
 
-echo "== yamllint =="
-run yamllint .
+# YAML files that differ from HEAD, including new files that are not staged yet.
+yaml_files=()
+if [ "$changed" = 1 ]; then
+  while IFS= read -r file; do
+    [ -n "$file" ] && yaml_files+=("$file")
+  done < <(
+    git diff --name-only --diff-filter=ACMR HEAD -- '*.yml' '*.yaml'
+    git ls-files --others --exclude-standard -- '*.yml' '*.yaml'
+  )
+fi
 
-echo "== ansible-lint =="
-run ansible-lint
+# ansible-lint only understands Ansible files, so keep the changed files that
+# live under a service with a playbook.
+ansible_files=()
+if [ "$changed" = 1 ]; then
+  for file in "${yaml_files[@]}"; do
+    service="${file%%/*}"
+    if [ -f "$service/playbook.yml" ]; then
+      ansible_files+=("$file")
+    fi
+  done
+fi
+
+if [ "$changed" = 1 ] && [ "${#yaml_files[@]}" -eq 0 ]; then
+  echo "== changed mode: no YAML files changed =="
+else
+  echo "== yamllint =="
+  if [ "$changed" = 1 ]; then
+    run yamllint "${yaml_files[@]}"
+  else
+    run yamllint .
+  fi
+
+  echo "== ansible-lint =="
+  if [ "$changed" = 1 ] && [ "${#ansible_files[@]}" -eq 0 ]; then
+    echo "no changed Ansible files"
+  elif [ "$changed" = 1 ]; then
+    run ansible-lint "${ansible_files[@]}"
+  else
+    run ansible-lint
+  fi
+fi
+
+echo "== layout =="
+layout_ok=1
+for playbook in */playbook.yml; do
+  service="${playbook%/playbook.yml}"
+  if [ ! -s "$service/readme.md" ]; then
+    echo "missing or empty $service/readme.md" >&2
+    layout_ok=0
+  fi
+done
+for entrypoint in */roles/*/tasks/main.yml */roles/*/handlers/main.yml; do
+  echo "role entrypoint must use .yaml: $entrypoint" >&2
+  layout_ok=0
+done
+if [ "$layout_ok" -ne 1 ]; then
+  exit 1
+fi
+
+echo "== gitleaks =="
+./scripts/check-secrets.sh
 
 echo "== ansible-playbook --syntax-check =="
-shopt -s nullglob
-for playbook in */playbook.yml; do
-  echo "-- $playbook"
-  ansible-playbook --syntax-check "$playbook"
-done
+playbooks=()
+if [ "$changed" = 1 ]; then
+  for file in "${yaml_files[@]}"; do
+    service="${file%%/*}"
+    if [ -f "$service/playbook.yml" ]; then
+      playbooks+=("$service/playbook.yml")
+    fi
+  done
+  if [ "${#playbooks[@]}" -gt 0 ]; then
+    mapfile -t playbooks < <(printf '%s\n' "${playbooks[@]}" | sort -u)
+  fi
+else
+  playbooks=(*/playbook.yml)
+fi
+
+if [ "${#playbooks[@]}" -eq 0 ]; then
+  echo "no playbooks to check"
+else
+  for playbook in "${playbooks[@]}"; do
+    echo "-- $playbook"
+    ansible-playbook --syntax-check "$playbook"
+  done
+fi