Run and track PageSpeed tests with GitHub Copilot in VS Code

Tracking PageSpeed scores with GitHub Copilot in VS Code means using its agent mode to read your stored scores and start a fresh test of the live site through xSpeed Hub, without leaving the editor.

list_sitesget_score_historyrun_speed_testget_benchmark_historyrun_benchmark

Last updated: October 2026

Example session · GitHub Copilot in VS Code

You: Using xSpeed Hub, does the lazy-loading change in this PR help blog on desktop?

get_score_history(site: blog) read-only
→ 4 stored runs; latest desktop 84, previous 83; LCP 1.9 s

GitHub Copilot in VS Code: The history shows a small rise before your change and no run after it. I can run a fresh desktop test of the live site, which takes up to two minutes. Run it?

You: Yes.

run_speed_test(site: blog, strategy: desktop) uses quota
→ desktop score 86, LCP 1.7 s, CLS 0.01, saved to the Hub report history

GitHub Copilot in VS Code: Desktop is 86 and LCP is 0.2 s lower. A two-point gain from one run is small, so I would not call it settled yet.

How GitHub Copilot in VS Code handles this

You are in VS Code, reviewing a branch for a WordPress theme, and the review comment says: does this make the site faster? Instead of switching to a browser, ask Copilot in agent mode. It calls get_score_history for the site and returns the stored PageSpeed runs, with score, LCP, FCP, CLS, TBT, Speed Index and TTFB, mobile and desktop. If the answer is old, it can follow with run_speed_test for a fresh reading, mobile or desktop, which takes up to about two minutes.

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. Chat: Manage Tool Approval lists the tools grouped by server. That is useful for the read tools, since get_score_history, get_benchmark_history and run_benchmark change nothing. run_benchmark gives the home page timing cached and uncached and no Lighthouse score, so use it when you only need to know whether the cache is warm, and use run_speed_test when you need a PageSpeed number.

The test measures the site connected to the Hub, so it reports the live site. A pull request that is not merged and deployed yet will not show a difference. Ask Copilot to write the before and after figures as a short comment you can paste into the review, naming the device and the date of each run. A test the Hub runs is saved in its own report history, the Reports tab of the dashboard, and get_score_history reads the plugin's stored runs, so it may not appear there. One call tests one device, so ask for each device separately.

Set up GitHub Copilot in VS Code once

Already connected? Skip to the prompts. Alternatives and troubleshooting are on the GitHub Copilot in VS Code guide.

1Put 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.

2Add 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.

mcp.json (MCP: Open User Configuration)

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

3Start 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.

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MCP: List Servers

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Full GitHub Copilot in VS Code setup, sign-in options and FAQ

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.

What do I ask?

Three prompts written for GitHub Copilot in VS Code. More for this job are below.

Prompt for GitHub Copilot in VS Code

With xSpeed Hub, read the PageSpeed history for shop and summarise the trend for the last four runs.

Prompt for GitHub Copilot in VS Code

This PR is deployed to the live blog site. Use xSpeed Hub to run a desktop test and add the score next to the previous one.

Prompt for GitHub Copilot in VS Code

Ask xSpeed Hub for the benchmark history of shop and say whether response time changed around the settings change I made on Monday.

What happens, step by step

PageSpeed Insights is Google's Lighthouse audit, and its score and Core Web Vitals are the numbers most people mean by "my speed". Through xSpeed Hub an agent can read the scores a site has already stored, run a new PageSpeed test on mobile or desktop, and read or run a separate benchmark of cached against uncached response time. The three answer different questions, and the Hub tells the agent which to use for each.

Read before you test

get_score_history returns the stored PageSpeed Insights and GTmetrix runs for a site: the score per run, with LCP, FCP, CLS, TBT, Speed Index and TTFB, mobile and desktop. It starts nothing. The Hub tells the agent to use it whenever you ask what your score is, or whether it improved, because a new test spends a shared allowance.

Run a new test when you need one

run_speed_test runs a real PageSpeed Insights audit on the site from the Hub and returns the score, the Core Web Vitals and the top opportunities. strategy is mobile (the default) or desktop, and one call tests one of them. It can take up to about 2 minutes, so the agent should say it is running before it calls.

Test the other device

Mobile and desktop scores differ, often by a lot. For both, the agent makes two calls, one per strategy. A failure is reported with its reason: PageSpeed not configured, quota reached, a timeout, or a site the audit cannot reach.

Measure the cache on its own

run_benchmark times the home page with the cache bypassed and again served from cache, and returns the response times. It is a read tool, and it accepts site: "all" for every site. It does not return a Lighthouse score, so the agent must not use it to answer a PageSpeed question.

Compare over time

get_benchmark_history returns past benchmark runs, uncached against cached, together with the settings changes on the same timeline, which is how you answer "did that change help?". For PageSpeed scores over time, use get_score_history.

Reference

Read stored scores	get_score_history (read): PageSpeed Insights and GTmetrix runs, starts nothing
Metrics per run	Score, LCP, FCP, CLS, TBT, Speed Index, TTFB, for mobile and desktop
Run a new test	run_speed_test (write, uses the shared allowance): one PageSpeed Insights run per call
strategy	mobile (default) or desktop
Duration	Up to about 2 minutes per run
Why a test is a write	It spends a shared PageSpeed allowance and stores a report; it changes nothing on the site
Read-only access	A connection token with Read-only everywhere on, or a Viewer member's sign-in: run_speed_test is refused; get_score_history, run_benchmark and get_benchmark_history still work. An OAuth sign-in gets the scopes the client asks for
Benchmark	run_benchmark (read): cached against uncached response time for the home page, no Lighthouse score
Benchmark history	get_benchmark_history (read): past runs plus settings changes on the same timeline
Scheduling	The Hub does not schedule PageSpeed tests itself; its daily pass only reads reports the plugin already stored
Where a new test is stored	In the Hub's own report history, the one the Hub dashboard shows

Rules worth keeping

Check the history first. Ask for stored scores before starting a test, and run a new one only when you want a fresh measurement or something changed.
Never answer a PageSpeed or Lighthouse question with run_benchmark. It times your own cache and carries no score.
run_speed_test changes nothing on your site, but the Hub classes it a write because it spends a shared allowance. A connection token with Read-only everywhere on, or a Viewer sign-in, refuses it. An OAuth sign-in gets the scopes the client asks for, so there your client's approval prompt is the gate.
Lab scores move a few points between runs of the same page. The agent should compare like with like, same site, same strategy, and not report one run's difference as a trend.
A new test does not run on a timer. If you want a regular test, the agent has to be started by something else, such as a scheduled job in your client, and a scheduled run that spends the allowance should be one you are comfortable leaving unattended.

Good to know with GitHub Copilot in VS Code

When the confirmation offers to allow a tool for the session, the workspace or all future calls, think before you accept that for run_speed_test. Every test after that in the same scope runs with no prompt, and each one spends the shared speed-test allowance. Allow all and Autopilot skip the prompts too, external tool calls included. Trust the read tools in Manage Tool Approval, and confirm run_speed_test one call at a time. A chat request can enable at most 128 tools and xSpeed adds 29, so deselect some if VS Code reports too many.

More prompts for this job

They work in any client connected to xSpeed Hub.

Prompt

Using xSpeed Hub, what is the mobile PageSpeed score for shop? Check the stored history before you run anything.

Prompt

Use xSpeed Hub to run a new mobile PageSpeed test on blog and tell me the score, LCP and the top opportunities.

Prompt

With xSpeed Hub, test shop on desktop and mobile and tell me which one is worse.

Prompt

Using xSpeed Hub, has the PageSpeed score on docs improved over the last few runs?

Prompt

Use xSpeed Hub to benchmark the cache on every site and tell me which one saves the least time.

Prompt

Did turning on minification on shop help? Use xSpeed Hub to compare the benchmark history around that change.

Prompt

My PageSpeed test failed on staging. Use xSpeed Hub to tell me why.

Frequently asked questions

Yes, in agent mode. With xSpeed Hub added as an MCP server, Copilot calls run_speed_test for a site and reports the score with its Core Web Vitals. The call can take up to about two minutes, and VS Code shows a confirmation before it runs unless you auto-approved the tool.

No. The test runs against the live address connected to the Hub. A branch that has not been merged and deployed will not change the result, so compare the score before and after the deploy, not before and after the commit.

run_speed_test runs a real PageSpeed Insights audit and returns a Lighthouse score with Core Web Vitals. run_benchmark measures how fast your own cache answers compared with an uncached request for the home page, and returns no Lighthouse score. Use the first for "what is my PageSpeed score" and the second for "is my caching working".

A single run can take up to about 2 minutes, so the agent should tell you it has started before it calls. One call tests one device, mobile or desktop, so checking both takes two calls.

Yes. get_score_history reads the stored PageSpeed Insights and GTmetrix runs for the site and starts nothing. The Hub tells the agent to read it first whenever you ask what your score is, because a new test spends a shared allowance.

No. The Hub does not schedule PageSpeed tests itself. Its daily pass re-verifies sites, snapshots cache status and pulls the PageSpeed and GTmetrix reports the plugin has already stored, and it can alert on a score regression. If you want regular new tests, they have to be started by a client that can run scheduled jobs.

It does not change your site. The Hub classes run_speed_test as a write because it spends a shared PageSpeed allowance and stores a report, and a read-only connection (the connection token with Read-only everywhere on, or a Viewer sign-in) should not be able to cost the owner anything. Such a connection can still read stored scores with get_score_history.

Keep going

Track PageSpeed scores with other agents

More with GitHub Copilot in VS Code

Purge the cache Find out why pages are not cached Scan a site's speed Raise the PageSpeed score Tune cache settings Warm the cache Set up Redis object cache Manage Cloudflare Manage every site at once

Documentation

From the blog

Track PageSpeed scores, from GitHub Copilot in VS Code.

xSpeed Hub is free and has no site cap. Connect your sites once and ask from the agent you already use.

Open xSpeed Hub GitHub Copilot in VS Code setup