# Raise a WordPress site's PageSpeed score with Gemini CLI

> Raising a WordPress PageSpeed score with Gemini CLI means asking it in your terminal to preview and then apply an xSpeed optimization pass through xSpeed Hub, approving each tool call.

Page: https://xspeedcache.com/agent/gemini-cli/optimize-site/
Last updated: October 2026

In Gemini CLI you type the goal the way you would say it to a colleague: the docs site is slow on mobile, preview what xSpeed would change. Gemini calls list_sites to resolve the name and then optimize_site with dry_run on, and the CLI asks you to confirm the tool call before it runs. You get a plan, in order, with the level it picked and nothing changed on the site.

Tell it to apply the plan when you are ready. The pass runs each setting one at a time, checks the page after each change, and undoes anything that breaks it, for up to two minutes per site. If you want a number, name it and Gemini can send target_score and up to three rounds. That requires the Pro plugin on the site, and each round is a real measurement, so decide whether the number is worth the wait. xSpeed stops early on its own when rounds stop helping and reports why. Diminishing returns usually means what is left is outside what caching can reach.

Gemini then reports applied, undone and unfixable. If it says everything is already on, believe it and look at the unfixable list instead of rerunning. The Hub also gives Gemini a list of verify_urls and tells it to look at the pages before saying the pass went well. The plugin cannot run JavaScript, so a page that passes its HTML checks may still log an error in the browser. Open the listed pages yourself with the console open, then tell Gemini what you saw.

## Set up Gemini CLI once

### 1. Put your sites in xSpeed Hub

Sign in at app.xspeedcache.com with Google or email; the Hub is free and has no site cap. Then connect each WordPress site from its own dashboard: click Connect Hub in the xSpeed Cache top bar, then Connect via xSpeed Hub. Each site needs the free xSpeed Cache plugin.

### 2. Add xSpeed Hub to Gemini CLI

Run this once. --scope user writes the server to ~/.gemini/settings.json so it works in every project; without it Gemini CLI saves to the project's .gemini/settings.json, which is the default.

```bash
gemini mcp add --scope user --transport http xspeedhub https://app.xspeedcache.com/xspeed/mcp
```

### 3. Authenticate with /mcp auth

Start gemini and run /mcp auth xspeedhub. A browser page opens where you sign in to xSpeed Hub and approve access, and Gemini CLI receives the redirect on a local port. There is no token to paste, and the client keeps the credentials it receives. Run /mcp afterwards to check that xspeedhub shows as connected and lists its tools.

```
/mcp auth xspeedhub
```

Full setup: https://xspeedcache.com/agent/gemini-cli/

### Before you send a prompt that changes something

Reads change nothing on your sites, though contact_support emails xSpeed support. Writes run once your connection allows them, so your client's approval prompt and a read-only connection (the token's Read-only everywhere switch, or a Viewer sign-in) are the gates that matter. Gemini CLI shows a confirmation for an MCP tool call unless the server entry sets trust to true or you start Gemini CLI with --approval-mode=yolo (or --yolo), which approves every tool call. You can proceed once, always allow that tool, always allow the whole xspeedhub server, or cancel; the last two choices stop later prompts for those tools. Policy rules in ~/.gemini/policies can allow, deny or ask for a named tool by server and tool name. The Hub has no confirmation step of its own, so a trusted server, YOLO mode or an allow rule lets a write run as soon as your connection allows writes.

## Prompts

- Use xSpeed Hub to preview an optimization for docs at the standard level and wait for my confirmation.
- Apply it through xSpeed Hub with a target score of 90 and at most two rounds, and tell me why it stopped when it finishes.
- List the verify URLs from the last xSpeed Hub run so I can open them.

## Example session

```
You: The docs site is slow on mobile. Preview what xSpeed Hub would change.
  → list_sites [read-only]: 3 sites; docs is docs.example.com
  → optimize_site(site: docs, aggressiveness: standard, dry_run: true) [dry run]: plan: 4 settings to apply (CSS minify, defer JS, lazy-load images, compression), nothing changed
Agent: The plan has four steps, covering CSS minify, script deferral, lazy-loading and compression. Nothing has changed. Apply it to docs?
You: Yes, apply it.
  → optimize_site(site: docs, aggressiveness: standard) [changes site]: applied 4, undone 0, unfixable: large code-sample images
Agent: All four settings are on. The remaining weight is in the code-sample images, which caching cannot shrink. Please open the docs home page and one long article, and check that the console shows no errors.
```

## How it works

1. **See where the site stands**: The agent reads get_score_history for the last stored scores and list_modules for which modules exist on that site and what state they are in. Neither changes anything.
2. **Preview with dry_run**: optimize_site with dry_run: true returns the plan: each change and its tier, what would be skipped (already on, or needing a higher aggressiveness) and what it cannot fix. Nothing is applied. The tool description tells the agent to prefer this before the first real run on a site you have not optimized before.
3. **Apply it**: optimize_site without dry_run applies the plan. aggressiveness is safe (removals and server-side changes only), standard (the default) or aggressive, which includes settings known to break some themes and should be opted into deliberately. A run can take up to about 2 minutes per site.
4. **Look at the site afterwards**: When changes were applied, the result carries verify_urls and a note. The site checks its own HTML and reverts anything that breaks it, but it cannot run JavaScript, so verified: true does not prove the page works in a browser. The Hub tells the agent to open those URLs and check the page renders and the console is clean, or to tell you which URLs to check.
5. **Reach for a number only if you named one**: target_score (1 to 100, Pro sites only) turns one pass into repeated rounds toward that score, up to max_rounds, with 3 as the most per site. Each round is a real PageSpeed measurement and up to about 2 minutes. The result says why it stopped, and diminishing returns means what is left is outside what caching can reach.
6. **Critical CSS on Pro sites**: generate_critical_css generates above-the-fold CSS so the first screen can paint without waiting for the full stylesheets. It needs the Pro Critical CSS module on that site, and the site answers with an unknown-tool error without it. Pages are rebuilt with it on their next build, so the agent purges the cache afterwards.

## Reference

| | |
| --- | --- |
| Main tool | optimize_site (write): measure, apply one setting at a time, verify, undo what breaks, re-measure |
| Preview | dry_run: true returns the plan and changes nothing |
| aggressiveness | safe, standard (default) or aggressive |
| Every site at once | site: "all" or a list of handles, one result per site, sites run one after another; the Hub's confirm-once instruction does not name optimize_site, so your client's prompt is the gate |
| Time | Up to about 2 minutes per site |
| target_score | 1 to 100; needs Pro on the site; without it the site runs one pass and says so |
| max_rounds | Up to 3 per site; only sent along with target_score; 12 rounds in total per call |
| Wide fan-out with a target | Each site gets fewer rounds, and the result carries a note saying so |
| Result fields | applied, skipped, reverted, unfixable, score, verified, rounds; verify_urls after a run that changed something |
| Already tuned site | Returns "everything is already on" plus what it cannot fix; that is an answer, not a failure |
| Critical CSS | generate_critical_css (write), Pro Critical CSS module required; purge_cache afterwards |
| Read-only connection | optimize_site and generate_critical_css are refused; dry_run is still a write call, so it is refused too. Applies to the connection token with Read-only everywhere on and to a Viewer sign-in, not to other OAuth sign-ins |

## Rules

- Run dry_run first. optimize_site changes live site settings as soon as your connection allows writes. The tool description tells the agent to preview first on a site that has not been optimized, but that is guidance, so your client's approval prompt and a read-only connection (the connection token with Read-only everywhere on, or a Viewer sign-in) are the real gates.
- Keep aggressive for a deliberate choice. It includes settings known to break some themes, and the agent should say so before using it.
- After a run that changed something, open the pages in verify_urls. The HTML checks cannot run JavaScript, so a page can pass them and still be broken in a browser. Do not call a run safe because verified is true.
- Relay the unfixable list. When a site is already tuned, the honest answer is that caching is done and the rest is page weight, hotlinked images or DOM size. The agent should not retry the tool or claim a gain it did not make.
- Only ask for target_score when you want the site driven to a number. Each round costs a real PageSpeed measurement, and a plain "make it faster" is one pass.

## Good to know with Gemini CLI

Gemini CLI asks before a tool call unless you have marked the server as trusted or started it with --approval-mode=yolo (or --yolo), which approves every tool call. A trust setting on the xSpeed Hub entry applies to every tool from that server, so optimize_site, generate_critical_css and purge_cache would all run without a prompt, and the Hub itself runs a write as soon as your connection allows it. Choosing always allow for optimize_site, or for the whole xspeedhub server, in a confirmation does the same for later calls, because the dry run and the real pass are the same tool. Choose proceed once while you tune a live site, so each call gets its own confirmation.

## More prompts for this job

They work in any client connected to xSpeed Hub.

- Ask xSpeed Hub to preview what optimize_site would change on shop with a safe pass. Do not apply anything.
- Use xSpeed Hub to optimize the blog site with the standard pass, then give me the pages to check by hand.
- With xSpeed Hub, get docs to a mobile PageSpeed score of 90 if you can, and tell me why it stopped if it does not get there.
- Use xSpeed Hub to show me what optimize_site would do on every site, as a dry run, and list which sites have the most left to change.
- Use xSpeed Hub to generate critical CSS for shop, then purge the cache so the pages are rebuilt with it.
- With xSpeed Hub, optimize shop, then compare the new PageSpeed score with the last stored one.
- Using xSpeed Hub, what could optimize_site not fix on the shop site?

## Frequently asked questions

### Does Gemini CLI ask before it applies an xSpeed optimization?

By default it asks before a tool call, unless the server is marked as trusted, an allow rule covers the tool, or you started the CLI with --approval-mode=yolo (or --yolo). You can proceed once, always allow that tool, always allow the whole server, or cancel. If you trust the Hub entry or pick an always allow choice for optimize_site, it runs without a prompt, so choose proceed once when you want a gate on the real pass.

### Can Gemini CLI target a PageSpeed score with xSpeed?

Yes, if you name a number it can pass target_score with up to three rounds. The site needs the Pro plugin, and without it the target is ignored and you get one pass. Each round costs a real PageSpeed measurement, and the run can stop early if rounds stop helping.

### What does optimize_site actually do?

It measures the site, applies the recommended xSpeed settings one at a time, checks that the page still renders after each change, and undoes any change that breaks it. It then reports what was applied, skipped and reverted, and what it could not fix. It reaches caching and asset delivery only.

### Should I run a dry run first?

Yes, especially on a site you have not optimized before. dry_run: true returns the plan, what would be skipped and what cannot be fixed, and changes nothing. The tool description tells the agent to prefer it, but nothing forces it, so say so in your prompt if you want a preview.

### Can I tell it to get my site to a score of 90?

Yes, with target_score, on a site that has xSpeed Pro. It repeats measure, apply and re-measure for up to 3 rounds per site and stops early when rounds stop helping, saying why. On a Free site the score target is ignored and you get a single pass with a note that no iterative tuner is installed.

### Why did it say everything is already on?

That is a real answer. The settings it can apply were already enabled, so there was nothing to change. The result also lists what it could not fix, such as page weight, images hosted on another domain or DOM size, and those need changes outside a caching plugin.

### Does the agent check that my pages still work?

The site checks its own HTML after each change and reverts anything that breaks it, but it cannot run JavaScript. After a run that changed something, the Hub tells the agent to open the returned verify_urls and check the page renders and the console is clean, or to give you the URLs to check yourself.

### Does generate_critical_css work on a Free site?

No. It needs the Pro Critical CSS module on that site, and without it the site answers with an unknown-tool error. On a Pro site, purge the cache afterwards, because pages already cached were built without the critical CSS.

## Raise the PageSpeed score with other agents

[Claude Code](https://xspeedcache.com/agent/claude-code/optimize-site/) · [Claude](https://xspeedcache.com/agent/claude/optimize-site/) · [Claude Cowork](https://xspeedcache.com/agent/claude-cowork/optimize-site/) · [ChatGPT](https://xspeedcache.com/agent/chatgpt/optimize-site/) · [Codex](https://xspeedcache.com/agent/codex/optimize-site/) · [Cursor](https://xspeedcache.com/agent/cursor/optimize-site/) · [GitHub Copilot in VS Code](https://xspeedcache.com/agent/github-copilot/optimize-site/) · [Windsurf](https://xspeedcache.com/agent/windsurf/optimize-site/) · [Antigravity](https://xspeedcache.com/agent/antigravity/optimize-site/) · [Zed](https://xspeedcache.com/agent/zed/optimize-site/) · [Kiro](https://xspeedcache.com/agent/kiro/optimize-site/) · [OpenCode](https://xspeedcache.com/agent/opencode/optimize-site/) · [OpenClaw](https://xspeedcache.com/agent/openclaw/optimize-site/) · [Hermes Agent](https://xspeedcache.com/agent/hermes-agent/optimize-site/) · [Grok Build](https://xspeedcache.com/agent/grok-build/optimize-site/) · [ChatGPT dots](https://xspeedcache.com/agent/chatgpt-dots/optimize-site/) · [Grok](https://xspeedcache.com/agent/grok/optimize-site/) · [Grok Bot](https://xspeedcache.com/agent/grok-bot/optimize-site/) · [Muse](https://xspeedcache.com/agent/muse/optimize-site/) · [Manus](https://xspeedcache.com/agent/manus/optimize-site/) · [Kimi Code](https://xspeedcache.com/agent/kimi/optimize-site/) · [Paperclip](https://xspeedcache.com/agent/paperclip/optimize-site/) · [NanoClaw](https://xspeedcache.com/agent/nanoclaw/optimize-site/)

## More with Gemini CLI

- [Purge the WordPress cache with Gemini CLI](https://xspeedcache.com/agent/gemini-cli/purge-cache/)
- [Find out why WordPress pages are not cached with Gemini CLI](https://xspeedcache.com/agent/gemini-cli/troubleshoot-cache/)
- [Scan a website for speed problems with Gemini CLI](https://xspeedcache.com/agent/gemini-cli/speed-scan/)
- [Run and track PageSpeed tests with Gemini CLI](https://xspeedcache.com/agent/gemini-cli/pagespeed-tests/)
- [Tune WordPress cache settings with Gemini CLI](https://xspeedcache.com/agent/gemini-cli/cache-settings/)
- [Warm the WordPress cache with Gemini CLI](https://xspeedcache.com/agent/gemini-cli/preload-cache/)
- [Set up the Redis object cache with Gemini CLI](https://xspeedcache.com/agent/gemini-cli/object-cache/)
- [Manage Cloudflare caching with Gemini CLI](https://xspeedcache.com/agent/gemini-cli/cloudflare/)
- [Manage every WordPress site at once with Gemini CLI](https://xspeedcache.com/agent/gemini-cli/fleet/)

## Documentation

- How to generate Critical CSS: https://xspeedcache.com/docs/critical-css/
- Performance recommendations: https://xspeedcache.com/docs/performance-recommendations/
- How to run a speed test: https://xspeedcache.com/docs/external-score/
- Free vs Pro: what is included: https://xspeedcache.com/docs/free-vs-pro/