Scan a website for speed problems with Windsurf

Scanning a site's speed with Windsurf means asking its agent, from the editor you code in, to run an xSpeed Scan and return the graded speed report with its shareable link.

list_sitesget_speed_scanrun_speed_scan

Last updated: October 2026

Example session · Windsurf

You: Use xSpeed Hub to scan the blog site and tell me if the homepage is in good shape.

run_speed_scan(site: blog, strategy: both) uses quota
→ Desktop grade B, mobile grade C. Failing on mobile: large images, one render-blocking stylesheet, page cache check. Report link included.

Windsurf: Desktop is fine. Mobile is a grade lower; its failing checks are large images, a render-blocking stylesheet and the page cache check. The report link is below if you want to share it.

You: Which of those can I fix from this project?

Windsurf: The stylesheet and the image sizes usually come from the theme, so I can look for them in this project. The cache check is a plugin setting, not code.

How Windsurf handles this

The scan fits into the loop you already have in the editor: change something, check it, change it again. You ask the agent to scan the site, it calls run_speed_scan through xSpeed Hub with the site handle, and about 50 seconds later you have a grade out of 100 and a ranked list of failing checks. The desktop run is the headline and the mobile run is graded beside it, so you can see at once if a change that helped one device hurt the other.

Windsurf now ships as Devin Desktop. New tabs start with the Devin Local agent, and the older Cascade agent stays for existing conversations. The tools do not differ between them: the agent sees the same Hub tools, including get_speed_scan, which reads a site's scan history without starting a new measurement. Use it first whenever the question is what a site scored, and spend a scan only when you need a fresh number.

For a site outside your Hub, add the no-account Scan MCP and give the agent a URL. It is read-only and limited to four scans per caller per ten minutes. Report links are the thing to carry out of the editor: paste one into a ticket or a client message and the other person sees the full report without Windsurf.

Set up Windsurf once

Already connected? Skip to the prompts. Alternatives and troubleshooting are on the Windsurf 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 for the Devin Local agent

Run this in a terminal. Devin Local shares its MCP configuration with Devin CLI, and -s user saves the server to ~/.config/devin/mcp_config.json (%APPDATA%\devin\mcp_config.json on Windows) so it applies to every project. Without -s, the command saves to local scope, which is the current project only.

Terminal

devin mcp add -s user xspeedhub https://app.xspeedcache.com/xspeed/mcp

3Sign in

Run the login command and approve access on the xSpeed Hub page that opens in your browser. There is no token to paste, and the client keeps the credentials it receives. If the server later shows Needs auth in the Devin Local MCP list, click Authenticate, or run devin mcp logout and then login again.

Terminal

devin mcp login xspeedhub

4Add the xSpeed Scan MCP for sites you do not run

Prompts that scan a public URL use the xSpeed Scan MCP, a separate server from the Hub. Add it to Windsurf the same way as the Hub above, as a second server (xspeedscan, for example) with the URL https://xspeedcache.com/scan/mcp, and leave out any sign-in setting, such as an OAuth or auth option or an Authorization header, because the Scan MCP needs no account, token or sign-in. On a plan that allows one custom connector, add whichever server the prompts you use need.

Text

https://xspeedcache.com/scan/mcp

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Full Windsurf 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. The Devin Local agent prompts for approval before it calls any MCP tool. In the prompt you can allow that one tool or every tool on the xspeedhub server, for this session or permanently, and permission rules such as mcp__xspeedhub__get_cache_status allow, deny or always ask for a named tool. Smart mode lets a fast model run what it judges safe without a prompt, and Bypass mode approves everything, so with either of those 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 Windsurf. More for this job are below.

Prompt for Windsurf

With xSpeed Hub, scan the site this project deploys to and give me the desktop and mobile grades with the report link.

Prompt for Windsurf

Ask xSpeed Hub what shop scored the last few times. Read the history, do not scan.

Prompt for Windsurf

Use xSpeed Hub to scan the homepage again after my last change and tell me if the top failing check is gone.

What happens, step by step

An xSpeed Scan grades a site from 0 to 100 using server probes (time to first byte, compression, cache evidence, redirects, platform detection) plus a Lighthouse run, and names the fix for every failing check. An agent can start one two ways. Through xSpeed Hub, run_speed_scan scans a site you have connected. Through the no-account Scan MCP at https://xspeedcache.com/scan/mcp, it scans any public URL and cannot change anything. Either way you get a report link to share.

Check what the site already scored

get_speed_scan without a scan id returns the site's scan history, newest first, plus a summary of the latest report. It starts nothing and spends nothing, so the Hub tells the agent to read it first when you ask what a site scored.

Start a scan

run_speed_scan runs the full scan on a site you connected to the Hub. strategy is both (the default), desktop or mobile; one device alone costs half the engine's quota. The scan takes 20 to 60 seconds. The Hub waits about 50 seconds and, if the scan is still running, hands back a scan id.

Poll if it is still running

Call get_speed_scan with scan_id. While the scan runs it returns the running status and a note to ask again in about 20 seconds. The report page is live from the start and refreshes itself.

Read the result

The summary carries the grade, the four dimension scores, what was measured and the top fixes ranked by points recoverable, each with the xSpeed feature that fixes it. The headline grade is the desktop run. The mobile run is graded alongside it, so the agent should mention both when they differ.

Scan a site you do not run

For any other public URL, the agent uses the Scan MCP at https://xspeedcache.com/scan/mcp. There is no account and no sign-in. It takes a url, returns the same graded report and a link at xspeedcache.com/scan/r/<id>, and is limited to 4 scans per caller per 10 minutes.

Fix, wait, re-scan

After a change, wait several minutes and scan again with fresh: true. Without it, the scan service reuses any report from the last 10 minutes and the agent will show you the old number.

Reference

Hub route	run_speed_scan, then get_speed_scan with scan_id; only for sites connected to your Hub
Scan MCP route	https://xspeedcache.com/scan/mcp, no account, 5 tools, read-only, any public URL
Scan MCP limit	4 scans per caller per 10 minutes
Why run_speed_scan is a write	It spends a shared scan allowance and stores a report; it changes nothing on the site
Read-only Hub connection	run_speed_scan is refused; get_speed_scan still works. Applies to the connection token with Read-only everywhere on and to a Viewer sign-in; an OAuth sign-in gets the scopes the client asks for
Duration	20 to 60 seconds; the Hub waits about 50 seconds, then returns a scan id
Poll argument	scan_id on the Hub tool, scanId on the Scan MCP tool
strategy	both (default), desktop or mobile; one device costs half the quota and becomes the headline
fresh	true forces a new measurement; otherwise a report from the last 10 minutes is reused
Report link	xspeedcache.com/scan/r/<id>; add .md for a Markdown twin an agent can read
Report visibility	Hub scans are filed unlisted; Scan MCP scans are public in the scan directory by default

Rules worth keeping

Read before you spend. Ask for the scan history first; start a new scan only when you want a fresh measurement or something changed.
A report link is not private. An unlisted report is kept out of the scan directory and search, but anyone with the URL can open it. A scan started through the Scan MCP is public by default.
run_speed_scan changes nothing on your site, but the Hub classes it a write, so a read-only connection (the connection token with Read-only everywhere on, or a Viewer sign-in) refuses it and your client may prompt for it. Use get_speed_scan, or the Scan MCP for a public URL, when you want a strictly read-only route.
Compare like with like. A scan that lost its Lighthouse run is marked partial and is not comparable with a full one, and the lab grade is not the same as real-visitor Core Web Vitals, which the report shows separately.
A scan cannot reach private, local or password-protected sites, and a site behind a bot challenge returns a report that says its server checks were not measured.

Good to know with Windsurf

Windsurf is now delivered as Devin Desktop, and menu labels may still say Windsurf in places. Devin Local prompts before it calls any MCP tool, and you can allow one tool or the whole xspeedhub server for the session or permanently. Allow get_speed_scan on its own and leave run_speed_scan on the prompt, because the Hub classes it as a write tool that spends the shared speed-test allowance. Smart mode lets a fast model run what it judges safe, and Bypass mode approves everything, so with either one a scan starts unasked. Cascade can use at most 100 tools at a time across all servers, and each client keeps its own sign-in. A read-only Hub connection (the connection token with Read-only everywhere on, or a Viewer sign-in) refuses run_speed_scan in every mode.

More prompts for this job

Prompts about your own sites work in any client connected to xSpeed Hub. A prompt that scans a site you do not run, or names the scan server, needs the xSpeed Scan MCP from the setup above.

Prompt

Using xSpeed Hub, what did the shop site score on its last speed scan? Do not start a new one.

Prompt

Use xSpeed Hub to run a speed scan on blog and give me the three fixes that recover the most points, plus the report link.

Prompt

With xSpeed Hub, scan only the mobile view of shop and tell me the grade.

Prompt

I changed the theme this morning. Use xSpeed Hub to run a fresh scan on docs and compare it with the previous report.

Prompt

Use the xSpeed Scan MCP to grade [competitor URL] and tell me what its biggest weaknesses are.

Prompt

The speed scan on shop is still running. Ask xSpeed Hub to check it again and tell me when it finishes.

Frequently asked questions

The scan does. xSpeed Hub and the Scan MCP are ordinary remote MCP servers, so any agent in the product that can use one gets the same tools. What differs is where you add the server and how the agent approves tool calls, so follow the Windsurf agent page for the steps.

Ask the agent to read the scan history with get_speed_scan. It returns the site's past reports and the latest summary and starts nothing. Only run_speed_scan starts a real measurement and spends the shared speed-test allowance.

run_speed_scan runs the full xSpeed Scan: server probes plus Lighthouse, a 0 to 100 grade across four dimensions, the fix for every failing check and a shareable report link. run_speed_test returns a raw PageSpeed Insights score with Core Web Vitals and no graded report.

Yes, through the xSpeed Scan MCP at https://xspeedcache.com/scan/mcp. It needs no account and no sign-in, accepts any public URL and is read-only. The Hub route only scans sites you connected to your own workspace.

The Scan MCP allows 4 scans per caller per 10 minutes. Scanning the same URL again within 10 minutes returns the existing report unless the agent passes fresh: true. A Hub scan spends a shared allowance of the scan service, which is why the Hub treats it as a write tool.

Reports started from the Hub are filed as unlisted, which keeps them out of the public scan directory and search results, but the link itself still opens for anyone who has it. Reports started through the Scan MCP are public by default.

The headline grade is the desktop run, because it is the one you can reproduce in your own browser. The mobile run is graded on the same rubric and returned alongside it. Google ranks on mobile, so when the two differ the agent should tell you both.

Keep going

Scan a site's speed with other agents

More with Windsurf

Purge the cache Find out why pages are not cached Track PageSpeed scores 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

Scan a site's speed, from Windsurf.

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

Open xSpeed Hub Windsurf setup