Run and track PageSpeed tests with Antigravity

Tracking PageSpeed scores with Antigravity means asking its agent for the stored PageSpeed history of your WordPress sites and, when needed, a fresh test, through an xSpeed Hub connection.

list_sitesget_score_historyrun_speed_testget_benchmark_historyrun_benchmark

Last updated: October 2026

Example session · Antigravity

You: Using xSpeed Hub, where does shop stand on PageSpeed right now?

get_score_history(site: shop) read-only
→ 5 stored runs; latest mobile 60, desktop 83, 4 days ago; mobile LCP 3.7 s

Antigravity: Mobile is 60 and desktop is 83, both from four days ago. Mobile is the weaker side, mostly on LCP. The history is recent enough that I would not start a new test unless you changed something. Want one anyway?

You: No, that is enough for now.

How Antigravity handles this

You are working on a site in Antigravity and the question that interrupts you is simple: where does this site stand on PageSpeed right now? Ask the agent, and it calls get_score_history through the Hub. The reply is the stored runs, with the score, LCP, FCP, CLS, TBT, Speed Index and TTFB for mobile and desktop, plus the dates. That answers most "has it got better" questions without starting anything new.

A fresh measurement is a different call. run_speed_test starts a PageSpeed Insights run from the Hub, mobile or desktop, and takes up to about two minutes. It is classed as a write, because each run spends the shared speed-test allowance. The cached-versus-uncached timing from run_benchmark is read-only, but it has no Lighthouse score, so keep the two apart when you read the answer.

Antigravity runs MCP tools you have not configured in Ask mode, so each call waits for your approval in a card. Allow rules in the form mcp(xspeedhub/get_score_history) let a named tool through without a prompt, Deny and Ask rules beat Allow, and the Turbo permission preset allows MCP actions without asking. The scope on the Hub connection does not depend on any of that. If you only want to look at history, connect read-only, with the connection token and Read-only everywhere on or a Viewer sign-in: the Hub then refuses run_speed_test with a clear message, whatever the editor does, and get_score_history and run_benchmark keep working. One more detail: a test started through the Hub is saved in the Hub's own report history on its Reports tab, and get_score_history reads the plugin's stored runs, so a fresh test can be absent from that answer. Each call tests one device, mobile or desktop.

Set up Antigravity once

Already connected? Skip to the prompts. Alternatives and troubleshooting are on the Antigravity 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 mcp_config.json

Antigravity reads ~/.gemini/config/mcp_config.json for every project, or .agents/mcp_config.json inside one workspace. In the IDE, open the ... menu at the top of the agent side panel, choose MCP Servers, then Manage MCP Servers and View raw config. Remote servers must use the serverUrl field; the older url and httpUrl fields are not supported.

~/.gemini/config/mcp_config.json

{
  "mcpServers": {
    "xspeedhub": {
      "serverUrl": "https://app.xspeedcache.com/xspeed/mcp"
    }
  }
}

3Authenticate

Open Agent settings with Cmd+, on macOS or Ctrl+, on Windows and Linux, go to the Customizations tab and click Authenticate next to xspeedhub. Sign in to xSpeed Hub in the browser and approve access, copy the authorization code the page shows, paste it into the settings panel and click Submit. Antigravity keeps the credentials it receives and refreshes them. In the CLI, type /mcp to open the MCP manager and check the server status.

Text

Settings → Customizations → Authenticate

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Full Antigravity 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. Antigravity runs unconfigured MCP tools in Ask mode, so each call waits for your approval in a card before it executes. Allow rules such as mcp(xspeedhub/get_cache_status) or mcp(xspeedhub/*) let calls through without a prompt, Ask and Deny rules take precedence over Allow, and the Turbo permission preset allows MCP and web actions without asking. When you approve a card you can also edit its target to widen the grant. With Turbo or a broad allow rule, a write reaches the Hub as soon as your connection allows writes. xSpeed Hub has no confirmation step of its own.

What do I ask?

Three prompts written for Antigravity. More for this job are below.

Prompt for Antigravity

Ask xSpeed Hub for the stored PageSpeed runs on shop and say which device is weaker.

Prompt for Antigravity

Using xSpeed Hub, what was the last desktop score on blog and how old is it?

Prompt for Antigravity

Use xSpeed Hub to run a mobile test on shop and compare it with the previous mobile run.

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 Antigravity

Antigravity asks by default, but two things remove the prompt: the Turbo preset, and an allow rule written for the whole server as mcp(xspeedhub/*). Either one lets run_speed_test start with no card in front of you, because the Hub runs a write as soon as the connection allows writes. When you approve a card you can edit its target to widen the grant, so read what you are approving. Name the read tools in allow rules, add an Ask rule for run_speed_test if you use Turbo, or connect read-only (the connection token with Read-only everywhere on, or a Viewer sign-in), which refuses every write tool with a message saying so.

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

Use a read-only connection to the Hub: the connection token with Read-only everywhere on, or a Viewer sign-in. A read-only connection refuses every write tool, run_speed_test included, with a message that says the connection is read-only. Reading get_score_history and running run_benchmark still work. A Deny rule for run_speed_test also works, because Deny beats Allow.

It is enough to see a trend. get_score_history returns the runs already stored, including the plugin's stored PageSpeed and GTmetrix reports, and starts nothing. A run_speed_test gives you a new reading whenever you need one, but the Hub saves it in its own report history, so it may not show up in get_score_history.

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 Antigravity

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 Antigravity.

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

Open xSpeed Hub Antigravity setup