# Raise a WordPress site's PageSpeed score with GitHub Copilot in VS Code

> Raising a WordPress PageSpeed score with GitHub Copilot in VS Code means asking its chat to preview and then apply an xSpeed optimization pass through xSpeed Hub, confirming each tool call.

Page: https://xspeedcache.com/agent/github-copilot/optimize-site/
Last updated: October 2026

You are in VS Code, probably with the theme or a plugin repository open, and you open Copilot chat and ask for a faster site. Copilot lists your sites, then calls optimize_site with dry_run on. At the default Manual permissions level, VS Code shows a confirmation dialog for any tool call that is not auto-approved. Confirm it, and you get the plan back in the chat: which settings xSpeed would turn on at the standard level, with nothing changed on the site.

Read the plan against what you know of the theme, then ask Copilot to apply it. The real pass applies each setting one at a time, checks the page after each, and undoes anything that breaks it. Give it up to two minutes per site. The answer lists what was applied, what was undone and why, and what is unfixable, so a score that stays lower than you hoped has a stated reason rather than a vague one. A site that is already tuned says everything is already on, and that is a complete result.

Copilot can also use your editor context to help with the leftovers. The unfixable list names what caching cannot reach, and those are things you can fix in the project open beside the chat. When the pass is done, the Hub gives Copilot a list of verify_urls and tells it to look at the pages before it says the pass worked. The plugin cannot run your JavaScript, so open those pages in a browser with the console visible and report anything odd back into the chat.

## Set up GitHub Copilot in VS Code 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 your user mcp.json

Open the Command Palette and run MCP: Open User Configuration, then add this entry. Servers in your user profile are available in every workspace. MCP: Add Server walks you through the same thing, and the project-level .mcp.json file works too if you want the entry shared with your team; that file uses a top-level mcpServers object instead of servers.

File: `mcp.json (MCP: Open User Configuration)`

```json
{
  "servers": {
    "xspeedhub": {
      "type": "http",
      "url": "https://app.xspeedcache.com/xspeed/mcp"
    }
  }
}
```

### 3. Start the server and sign in

Run MCP: List Servers, pick xspeedhub and choose Start. VS Code asks whether you trust the server, then opens a browser page where you sign in to xSpeed Hub and approve access. There is no token to paste, and VS Code keeps the credentials it receives. Open the Chat view and use the Configure Tools button to see the xSpeed tools.

```
MCP: List Servers
```

Full setup: https://xspeedcache.com/agent/github-copilot/

### 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. In VS Code the default permission level is Manual permissions: a tool call that is not auto-approved shows a confirmation, and you can allow it once or for the session, the workspace or all future calls. Chat: Manage Tool Approval lists tools grouped by MCP server, so you can trust get_cache_status and the other reads while purge_cache and update_settings stay on a prompt. Allow all, Autopilot and global auto-approval skip those prompts, including for external tool calls, and then a write runs as soon as your connection allows writes. xSpeed Hub has no confirmation step of its own.

## Prompts

- Ask xSpeed Hub for a preview of the optimization on the portfolio site at the safe level, and show me the plan before anything is applied.
- Using xSpeed Hub, apply that plan to portfolio, then list the pages I should check and what an error would look like.
- Which items on the xSpeed Hub unfixable list can be fixed in the files open in this workspace?

## Example session

```
You: The portfolio site scores badly on mobile. See what xSpeed Hub can do, safe level only.
  → list_sites [read-only]: 3 sites; portfolio is portfolio.example.com
  → optimize_site(site: portfolio, aggressiveness: safe, dry_run: true) [dry run]: plan: 3 settings to apply (lazy-load images, compression, browser cache), nothing changed
Agent: At the safe level it would turn on lazy-loading, compression and browser caching. Nothing has changed yet. Apply these three to portfolio?
You: Yes.
  → optimize_site(site: portfolio, aggressiveness: safe) [changes site]: applied 3, undone 0, unfixable: 1 video background, large gallery images
Agent: All three settings are on. The video background and the gallery images are on the unfixable list, so the score may stay below what you want until those change. Open the home page and the gallery in a browser and check the console.
```

## 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 GitHub Copilot in VS Code

The VS Code confirmation dialog can allow a tool once, or for the session, the workspace or all future calls, and a broader choice outlives the one call. If you accept it for optimize_site while previewing, the real pass follows with no dialog at all, because the dry run and the real pass are the same tool. Allow it once, and use Chat: Manage Tool Approval to trust the reads while optimize_site stays on a prompt. Allow all, Autopilot and global auto-approval skip the dialog for every tool. A chat request can enable at most 128 tools, and the Hub adds 29 to the pool.

## 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

### Will VS Code ask me before Copilot optimizes a WordPress site?

By default, yes. VS Code starts in Manual permissions and shows a confirmation for tool calls that are not auto-approved, and you can allow a tool once, for the session, for the workspace or for all future calls. If you allow it broadly, or choose Allow all or Autopilot, later calls run without a dialog, and the Hub runs the pass as soon as your connection allows writes.

### How many xSpeed tools does Copilot load in VS Code?

The Hub exposes 29 tools. A chat request can enable at most 128 tools across all sources, so xSpeed fits, but a crowded setup may need some servers or tools switched off in the tools picker.

### 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/) · [Windsurf](https://xspeedcache.com/agent/windsurf/optimize-site/) · [Gemini CLI](https://xspeedcache.com/agent/gemini-cli/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 GitHub Copilot in VS Code

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