agent-skills/skills/wordpress-performance-diagnostics/references/diagnostic-tools.md

Deeper diagnostic tools (still read-only, still backend-only)

Load this file only once the four core baseline metrics (TTFB, autoload size, object-cache presence, cron health — see SKILL.md Step 3) haven't explained the symptom. Every command here still goes through the fleet's bastille cmd ... su -m www -c "wp ..." wrapper from SKILL.md Step 2 — abbreviated to bare wp ... below for readability.

wp doctor — quick production-readiness checks

Catches common footguns fast: autoload bloat, SAVEQUERIES/WP_DEBUG left on, stale plugin/core versions.

wp doctor check
wp doctor list   # see available checks

Install if missing (this is a write action — confirm it's acceptable before running it, per Step 0):

wp package install wp-cli/doctor-command

Checks especially relevant to performance:

• autoload-options-size — autoloaded-options threshold
• constant-savequeries-falsy / constant-wp-debug-falsy — flags perf-costly debug constants left on in what should be production
• cron checks (event count / duplicates)

Docs: default checks — https://make.wordpress.org/cli/handbook/doctor-default-checks/ · customizing checks — https://make.wordpress.org/cli/handbook/guides/doctor/doctor-customize-config/

wp profile — hook/stage-level profiling without a browser

Install if missing (write action, confirm first):

wp package install wp-cli/profile-command

Recommended sequence:

1. Stage overview — where time goes across bootstrap/main_query/template:

   wp profile stage --fields=stage,time,cache_ratio [--url=<url>]
   

2. Hook hotspots:

   wp profile hook --spotlight [--url=<url>]
   wp profile hook init --spotlight [--url=<url>]   # drill into one hook
   

3. Targeted eval:

   wp profile eval 'do_action("init");' --hook=init
   

Use --url= to profile a specific site/route on a multisite-adjacent setup. --skip-plugins/--skip-themes can isolate a culprit component, but changes real behavior while active — note that in the report if you use it, don't silently profile a degraded version of the site.

Docs: https://wpcli.dev/docs/profile/stage · https://wpcli.dev/docs/profile/hook · https://wpcli.dev/docs/profile/eval

Query Monitor, used headlessly

Query Monitor is normally UI-driven, but it exposes data through authenticated REST response headers/envelope — no browser required.

1. Confirm the plugin is active: bastille cmd <jail> test -f <site-path>/wp-content/plugins/query-monitor/query-monitor.php.
2. Authenticate against the REST API — a nonce, or an Application Password (see Redaction in SKILL.md: never paste a generated Application Password into a report).
3. Request a REST route and inspect response headers (x-qm-overview-* etc.), or request an enveloped response (?_envelope) to get a qm property containing DB query details, cache stats, and HTTP API call details in one payload.

Configuration constants: https://querymonitor.com/help/configuration-constants/ · REST-API-specific docs: https://querymonitor.com/wordpress-debugging/rest-api-requests/ · plugin page: https://wordpress.org/plugins/query-monitor/

Guardrails: Query Monitor adds real overhead — don't enable it in production without approval. If a hosting platform pre-installs it gated behind a capability, you may need view_query_monitor granted to the authenticating user.

Server-Timing headers (if Performance Lab is present)

curl -sS -D - -H 'Host: <domain>' http://<jail-ip>/ -o /dev/null | grep -i '^server-timing:'

Requires the Performance Lab plugin (or a module of it) enabled — https://wordpress.org/plugins/performance-lab/. Don't enable experimental modules in production without approval; this is a nice-to-have on top of the four core baseline metrics, not a replacement for them.

Benchmarking guidance: https://make.wordpress.org/performance/handbook/measuring-performance/benchmarking-server-timing/

General measurement discipline

• Always capture a baseline before changing anything.
• Keep the test scenario fixed — same URL/route, same logged-in-or-not state, same underlying data.
• Prefer multiple samples and a median over a single run.

Measuring-performance handbook: https://make.wordpress.org/performance/handbook/measuring-performance/