# Warm the WordPress cache with Hermes Agent

> Warming the WordPress cache with Hermes Agent means letting an always-on agent run xSpeed preloader jobs on cron through xSpeed Hub, starting crawls, stopping them and reporting each site's progress.

Page: https://xspeedcache.com/agent/hermes-agent/preload-cache/
Last updated: October 2026

Hermes Agent runs continuously and has cron jobs, so the preloader can fit your day instead of your keyboard. A useful pair is a start and a stop. At night the job calls start_preloader on each site so the cache is warm before the morning rush, and at the start of business hours a second job calls stop_preloader if a crawl is still running. Pages already warmed stay cached, so the stop costs nothing.

In between, a small job can read get_preloader_status on every site and write you a morning summary: which crawls finished, which are still running, which sites were idle. That job is a read and changes nothing, which makes it the right one to leave running for weeks. The Hub does not provide the timer. It runs its own daily checks and alerts, but the schedule for these jobs is Hermes Agent's, and its cron scheduler lives in the gateway process, so the gateway has to be running.

You sign in to the Hub once through the browser with hermes mcp login, and Hermes caches the credentials it receives and refreshes them, so a cron job can call the tools later with nobody present. Background runs, the gateway and cron never open a browser, so if a refresh token stops working the server is parked until you run the login again. Approval is a trust setting on the server entry. The default, full, adds no prompt, and the approvals setting covers dangerous shell commands, not MCP tools. Set trust to untrusted and Hermes asks before every call to a tool without a read-only hint. The Hub sets none, so every call would ask, reads included, and a cron tick has nobody to answer. For an unattended job, filter with a tools include list instead. Because the same agent holds both jobs, you can ask it for the whole schedule in one message and read it back, which is the quickest way to spot a gap between the start and the stop.

## Set up Hermes Agent 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 config.yaml

Add this entry under mcp_servers. auth: oauth tells Hermes to handle discovery, dynamic client registration, PKCE and token refresh itself. If you edit the file from inside a running session, Hermes reloads its MCP connections with a 30 second timeout, which is too short for a browser sign-in, so finish the entry and then run the login in the next step.

File: `~/.hermes/config.yaml`

```yaml
mcp_servers:
  xspeedhub:
    url: "https://app.xspeedcache.com/xspeed/mcp"
    auth: oauth
```

### 3. Sign in with hermes mcp login

Run this once. Hermes prints an authorization URL, opens your browser where it can, and waits for the callback on a local loopback port. Sign in to xSpeed Hub and approve. There is no token to paste; Hermes caches the credentials it receives under ~/.hermes/mcp-tokens. On a remote host, paste the redirect URL back into the terminal when Hermes asks, or forward the callback port over SSH.

```bash
hermes mcp login xspeedhub
hermes mcp test xspeedhub
```

Full setup: https://xspeedcache.com/agent/hermes-agent/

### 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. A Hermes server entry has a trust setting. The default, full, adds no approval prompt for that server's tools, and the approvals setting covers dangerous shell commands, not MCP tools. Set trust: untrusted on the xspeedhub entry and Hermes asks before every call to a tool that lacks a readOnlyHint of true. The Hub does not mark its tools that way, so with untrusted every Hub call asks, reads included. To remove writes instead of prompting, set tools.include on the entry to the read tools; the filter takes globs and include wins over exclude. The Hub itself has no confirmation step.

## Prompts

- With xSpeed Hub, start the preloader on shop and blog at 1am. At 8am stop it on any site where it is still running.
- Every morning, ask xSpeed Hub for the preloader status on all sites and send me a short summary.
- Use xSpeed Hub to run a one-off warm on docs now and tell me how many pages are done in ten minutes.

## Example session

```
You: Add two cron jobs for shop that use xSpeed Hub: start the preloader at 1am, stop it at 8am if it is still running.
Agent: Both jobs are saved. I will run the status check now to see where shop stands before the first one fires.
  → get_preloader_status(site: shop) [read-only]: Idle, no run in progress
Agent: shop is idle, so the 1am job will start fresh. At 8am the stop job calls stop_preloader only if a run is active, and pages already warmed stay cached.
```

## How it works

1. **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.
2. **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.
3. **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.
4. **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.
5. **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.
6. **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

- 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 Hermes Agent

Cron jobs that start or stop crawls run unattended, and a scheduled tick has nobody to answer a prompt. Under the default trust setting Hermes adds no prompt, so a write goes through as soon as your connection allows it. For a job that only reports, set a tools include list on the entry to the read tools, or use the connection token with Read-only everywhere on (or a Viewer sign-in) so the Hub refuses every write. Filters take the original tool names, such as start_preloader. For a job that must write, include only start_preloader, stop_preloader and get_preloader_status, name the sites explicitly instead of using site: "all", and read the first few runs' reports yourself.

## 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

### Can Hermes Agent stop a crawl at a set time?

Yes. A cron job can call stop_preloader on the sites you name at the time you choose. Stopping is safe mid-run, since the pages already warmed stay cached. The Hub itself has no scheduler, so the timer is Hermes Agent's.

### How do I make a Hermes Agent job only look and not change anything?

Set a tools include list on the xspeedhub entry that holds only get_preloader_status, or give that agent the connection token with Read-only everywhere on (or a Viewer sign-in). The Hub refuses every write tool on a read-only connection, so a job that goes wrong still cannot start or stop a crawl.

### Why does start_preloader say the preloader is disabled?

The preloader module is off by default on a new install, and the site refuses to start a crawl until it is on. The agent can switch it on with update_settings on the preloader module, or you can turn it on in the xSpeed Cache panel in wp-admin. Page caching also has to be on, because the crawl exists to fill that cache.

### What does the preloader actually warm?

It reads the site's sitemap, which is the WordPress one at /wp-sitemap.xml unless you set a different sitemap URL, follows nested sitemap indexes and skips any URL your cache exclusion rules leave out. If the sitemap cannot be read, the site falls back to a list built from its own content and says so. If nothing at all is queued, the call reports an error with the reason.

### Can I warm every site with one prompt?

Yes. The agent passes site: "all" to start_preloader and the Hub starts the crawl on every site in the workspace one after another, returning a result per site. The Hub tells the agent to confirm that with you once first. The call only starts the crawls, so progress is read afterwards with get_preloader_status, one site at a time.

### Will warming slow my site down?

A crawl fetches your own pages, a few per run, so it adds load while it runs. The Pages per run setting controls how many, from 1 to 50 with a default of 5. If a site struggles, stop_preloader ends the crawl and the pages already warmed stay cached.

### Why do some pages fail with HTTP 403 or 406?

Those codes are what bad-bot firewall rules usually answer with, and they mean the warmer was judged by its user-agent, not that the page is missing. The warmer identifies itself as xSpeed-Warmer/1.0. Allow that user-agent in the server rule, or change it with the xspeed_preloader_user_agent filter, and run the crawl again.

### Can the agent keep my cache warm on a schedule?

The preloader has its own Schedule setting in WordPress: manual, hourly, daily or weekly. An agent can change it with update_settings. The Hub itself has no scheduler for agent prompts, so a prompt only runs when you send it or when your AI client runs it on a timer.

## Warm the cache with other agents

[Claude Code](https://xspeedcache.com/agent/claude-code/preload-cache/) · [Claude](https://xspeedcache.com/agent/claude/preload-cache/) · [Claude Cowork](https://xspeedcache.com/agent/claude-cowork/preload-cache/) · [ChatGPT](https://xspeedcache.com/agent/chatgpt/preload-cache/) · [Codex](https://xspeedcache.com/agent/codex/preload-cache/) · [Cursor](https://xspeedcache.com/agent/cursor/preload-cache/) · [GitHub Copilot in VS Code](https://xspeedcache.com/agent/github-copilot/preload-cache/) · [Windsurf](https://xspeedcache.com/agent/windsurf/preload-cache/) · [Gemini CLI](https://xspeedcache.com/agent/gemini-cli/preload-cache/) · [Antigravity](https://xspeedcache.com/agent/antigravity/preload-cache/) · [Zed](https://xspeedcache.com/agent/zed/preload-cache/) · [Kiro](https://xspeedcache.com/agent/kiro/preload-cache/) · [OpenCode](https://xspeedcache.com/agent/opencode/preload-cache/) · [OpenClaw](https://xspeedcache.com/agent/openclaw/preload-cache/) · [Grok Build](https://xspeedcache.com/agent/grok-build/preload-cache/) · [ChatGPT dots](https://xspeedcache.com/agent/chatgpt-dots/preload-cache/) · [Grok](https://xspeedcache.com/agent/grok/preload-cache/) · [Grok Bot](https://xspeedcache.com/agent/grok-bot/preload-cache/) · [Muse](https://xspeedcache.com/agent/muse/preload-cache/) · [Manus](https://xspeedcache.com/agent/manus/preload-cache/) · [Kimi Code](https://xspeedcache.com/agent/kimi/preload-cache/) · [Paperclip](https://xspeedcache.com/agent/paperclip/preload-cache/) · [NanoClaw](https://xspeedcache.com/agent/nanoclaw/preload-cache/)

## More with Hermes Agent

- [Purge the WordPress cache with Hermes Agent](https://xspeedcache.com/agent/hermes-agent/purge-cache/)
- [Find out why WordPress pages are not cached with Hermes Agent](https://xspeedcache.com/agent/hermes-agent/troubleshoot-cache/)
- [Scan a website for speed problems with Hermes Agent](https://xspeedcache.com/agent/hermes-agent/speed-scan/)
- [Run and track PageSpeed tests with Hermes Agent](https://xspeedcache.com/agent/hermes-agent/pagespeed-tests/)
- [Raise a WordPress site's PageSpeed score with Hermes Agent](https://xspeedcache.com/agent/hermes-agent/optimize-site/)
- [Tune WordPress cache settings with Hermes Agent](https://xspeedcache.com/agent/hermes-agent/cache-settings/)
- [Set up the Redis object cache with Hermes Agent](https://xspeedcache.com/agent/hermes-agent/object-cache/)
- [Manage Cloudflare caching with Hermes Agent](https://xspeedcache.com/agent/hermes-agent/cloudflare/)
- [Manage every WordPress site at once with Hermes Agent](https://xspeedcache.com/agent/hermes-agent/fleet/)

## Documentation

- How to warm your cache ahead of visitors: https://xspeedcache.com/docs/preloader/
- How to crawl your sitemap: https://xspeedcache.com/docs/crawl-now/
- How to enable Page Cache: https://xspeedcache.com/docs/page-cache/
- Managing your fleet with xSpeed Hub: https://xspeedcache.com/docs/managing-your-fleet-with-xspeed-hub/