How Claude Code handles this
The moment for this is right after a purge or a deploy. The cache is empty, the next visitors would pay for every rebuild, and you are already in the terminal. You type which site to warm. Claude Code matches the name against list_sites, calls start_preloader on that handle, and the plugin on the site begins crawling its sitemap in the background, a few URLs at a time through WP-Cron, so the server load stays gentle.
Starting is only half of it. Ask how it is going and Claude Code calls get_preloader_status, which says whether a run is active and how far through the URL list it has got. That call is a read, so it changes nothing and you can repeat it as often as you like. If the crawl collides with a busy hour, ask Claude Code to stop it. stop_preloader is safe mid-run, because the pages already warmed stay cached.
Claude Code lists each xSpeed tool under its own name, such as mcp__xspeedhub__start_preloader, so you decide per tool how much friction you want. A rule such as mcp__xspeedhub__get_* lets the status check run without a prompt, while start_preloader and stop_preloader stay behind one. For every site at once, the Hub tells Claude Code to say that this will touch all N sites and to wait for your yes before it sends a single call with site: "all".
Set up Claude Code once
Already connected? Skip to the prompts. Alternatives and troubleshooting are on the Claude 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 Claude Code
Run this once. --scope user makes the server available in every project; leave it off and it applies to the current project only, which is Claude Code's default.
claude mcp add --transport http --scope user xspeedhub https://app.xspeedcache.com/xspeed/mcp
3Sign in with /mcp
Start Claude Code, run /mcp, pick xspeedhub and finish the sign-in in your browser. You approve access on an xSpeed Hub page; there is no token to paste, and Claude Code keeps the credentials it receives and refreshes them.
/mcp
Full Claude 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. Claude Code asks before it runs an MCP tool unless a permission rule already allows it, or you work in auto mode, where a classifier reviews actions instead of you, or in bypassPermissions mode, which skips prompts. A rule such as mcp__xspeedhub__get_cache_status allows one tool, and mcp__xspeedhub__get_* allows every read whose name starts with get_. Keep purge_cache, update_settings, toggle_cache and the other write tools on the prompt, because the Hub itself runs a write as soon as your connection allows it.
What do I ask?
Three prompts written for Claude Code. More for this job are below.
Use xSpeed Hub to start the preloader on shop, then show me how many URLs it queued and how far the crawl has got.
I just deployed to blog. Using xSpeed Hub, is the preloader running there? If not, start it.
With xSpeed Hub, warm every site in my workspace, then tell me which ones refused to start.
What happens, step by step
The first visitor to an uncached page pays for building it. The preloader fixes that by visiting your pages first. Through xSpeed Hub an agent can start the crawl on one site or on every site in a workspace, watch how far it has got, and stop it. The crawl runs inside WordPress in the background; the agent only starts it, reads its progress and stops it.
01
Check the cache and the preloader
get_cache_status tells the agent whether page caching is on, because there is nothing to fill when it is off. get_preloader_status shows whether a crawl is already running, so the agent does not start a second one.
02
Make sure the preloader is switched on
The preloader module is off on a fresh install, and the site refuses start_preloader until it is on. The agent can read the module with get_settings and, if you agree, switch it on with update_settings on the preloader module. The Hub tells the agent to briefly confirm intent before an update_settings call, but that is guidance to the agent, not a lock.
03
Start the crawl
start_preloader makes the site read its sitemap, follow any nested sitemap indexes, drop URLs that your cache exclusion rules skip, and queue the rest. The call returns once the queue is built; the pages are then fetched in the background, a few per run. For every site at once the agent passes site: "all", and the Hub starts the sites one after another with a one-second pause.
04
Watch the progress
get_preloader_status reports whether a crawl is running, how many URLs it has processed out of the total, the last URL it visited and the most recent errors. It works on one site at a time, so for several sites the agent calls it once per site.
05
Read what failed
A page that answers 403 or 406 usually means a server firewall is blocking the warmer by its user-agent, not that the page is broken. The status message names the user-agent to allow. A crawl that queues no URLs is reported as an error with the reason, not as a success.
06
Stop it if the server struggles
stop_preloader ends a running crawl. It is safe mid-run: pages already warmed stay cached. The agent can stop one site or every site in the workspace.
Reference
| Start and stop | start_preloader and stop_preloader (write) |
|---|---|
| Progress | get_preloader_status (read): running or not, processed out of total, last URL, recent errors |
| What gets crawled | The sitemap (the WordPress one at /wp-sitemap.xml unless you set another), nested indexes followed, excluded URLs skipped |
| Needs | The preloader module switched on (it is off by default) and page caching on |
| Pages per run | 5 by default, 1 to 50, set in the preloader module |
| Schedule setting | manual, hourly, daily or weekly, set in the preloader module |
| Every site at once | start_preloader and stop_preloader accept site: "all"; get_preloader_status does not |
| Fan-out pacing | Sites start one after another with a 1 second pause, one result per site |
| Warmer user-agent | xSpeed-Warmer/1.0, the string a firewall rule would need to allow |
| Stopping | Safe mid-run; warmed pages stay cached |
| Read-only access | A Viewer member's sign-in, or the connection token with Read-only everywhere on: start_preloader and stop_preloader are refused; get_preloader_status works. An OAuth sign-in by anyone else gets the scopes the client asks for. |
| Confirmation | None on the Hub; your client's prompt is the gate |
Rules worth keeping
- Warm after a purge, not instead of one. The Hub tells the agent that starting the preloader after a purge saves the next visitor from paying for the rebuild.
- A crawl requests every page in the sitemap, so it adds load to the origin. Start with one site, and on a small host keep Pages per run low or stop the crawl if the site slows.
- start_preloader and stop_preloader are write tools. The Hub calls the preloader low-risk and only asks the agent to confirm when the target site is unclear or the call covers every site, so your client's approval prompt and read-only access (a Viewer sign-in, or the connection token with Read-only everywhere on) are the gates that matter.
- A fan-out only starts the crawls. Check each site with get_preloader_status afterwards, and treat some sites failing to start as a partial result, not a failure of the whole call.
Good to know with Claude Code
If you wrote an allow rule such as mcp__xspeedhub__* to stop the prompts, start_preloader and stop_preloader now run without one, on every site you name. Allow the get_ tools and keep the two preloader writes on the prompt. Auto mode and bypassPermissions mode skip the prompt for them as well. A failed start usually means the preloader module is switched off on that site, which Claude Code shows as a tool error. It did not start a crawl, so do not report the site as warm.
More prompts for this job
They work in any client connected to xSpeed Hub.
Use xSpeed Hub to start the preloader on shop and tell me how many URLs it queued.
Using xSpeed Hub, how far through its crawl is blog? Show processed against total and any errors.
With xSpeed Hub, purge the cache on docs, then warm it again.
Use xSpeed Hub to start the preloader on every site in my workspace and tell me which ones refused.
Use xSpeed Hub to stop the preloader on shop. It is slowing the server down.
The preloader on shop says it is disabled. Use xSpeed Hub to turn the module on, then start the crawl.
Using xSpeed Hub, which of my sites has no running crawl and a low hit ratio?
Frequently asked questions
Keep going
Warm the cache with other agents
More with Claude Code
Documentation
- How to warm your cache ahead of visitors
- How to crawl your sitemap
- How to enable Page Cache
- Managing your fleet with xSpeed Hub
- How to write prompts for xSpeed Hub
- Claude Code + xSpeed
- Every AI agent that works with xSpeed
From the blog