How Hermes Agent handles this
You run Hermes Agent as a long-lived assistant, and a member of your team reports that a members-only page showed someone else's dashboard for a moment. That is a cache exclusion problem, and you want it looked at across every site, not just the one you noticed. You ask Hermes Agent to read the cache module on each site and list the excluded URLs and cookies. It calls list_sites, then get_settings for the cache module on each site, one by one.
What comes back is a table in the conversation: for each site, which URLs are excluded, whether login or account paths are among them, and where a path that probably belongs there is missing. Nothing is written at that point. When you point at a site and say add this path, Hermes Agent calls update_settings, and the Hub tells it to briefly confirm intent before it does. The result is the stored list for that site. If any key or value is wrong, the whole call is refused and nothing is stored, Pro-only modules are refused without a licence, and credential fields are refused over the Hub.
What differs in Hermes Agent is trust. A server entry's default, full, adds no approval prompt for that server's tools, so a Hub write runs as soon as your connection allows it. Set trust to untrusted on the xspeedhub entry and Hermes asks before every call to a tool that lacks a read-only hint. The Hub marks none of its tools that way, so every Hub call asks, reads included. Hermes also has a cron scheduler in the gateway, so the same audit can run on a timer and message you when an exclusion disappears. A scheduled run has nobody to answer a prompt, so keep that job to reads.
Set up Hermes Agent once
Already connected? Skip to the prompts. Alternatives and troubleshooting are on the Hermes Agent 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 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.
mcp_servers:
xspeedhub:
url: "https://app.xspeedcache.com/xspeed/mcp"
auth: oauth 3Sign 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.
hermes mcp login xspeedhub hermes mcp test xspeedhub
Full Hermes Agent 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. 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.
What do I ask?
Three prompts written for Hermes Agent. More for this job are below.
Use xSpeed Hub to read the excluded URLs and cookies on every site and tell me where /my-account/ or /members/ is missing.
With xSpeed Hub, add /members/ to the cache exclusions on blog only, and show me the full list before and after.
Set up a daily check that asks xSpeed Hub for the cache exclusions on all sites and messages me if one of them changes.
What happens, step by step
Every xSpeed feature is a module with its own settings. Through xSpeed Hub an agent can list the modules a site has, read one module's settings, change them with a checked update, and turn page caching on or off. The site validates every write against the module's own schema, so a wrong key or value is refused with a reason instead of being quietly ignored.
01
List the modules
list_modules returns every Free and Pro module available on one site, with its settings schema and status. It tells the agent which module slugs exist, such as minify or gzip, and what each setting accepts.
02
Read the current settings
get_settings takes a module slug and returns its settings. Credential fields come back masked, so an agent cannot read a stored API token or password back in plain text.
03
Change them
update_settings takes the module and a values object of setting keys. The site checks the whole object first. If any key is unknown, any value is outside the schema, or a field is pinned by a constant in wp-config.php, it refuses the write, writes nothing and says which keys and why, sometimes with a "did you mean" hint.
04
Turn page caching on or off
Page caching has its own tool, toggle_cache, because it installs or removes the cache drop-in and the WP_CACHE constant. Asking update_settings to set cache_enabled does not work and is refused. If another caching plugin owns the drop-in, the site declines to enable xSpeed and returns blocked: true with the reason.
05
Check the effect
The result of a settings write is the stored settings. A module can add a warning when a setting is saved but has no effect on this server, for example Brotli on a server without the module for it, and the agent should pass that on. run_benchmark then times cached against uncached to see whether the change helped.
06
Apply to many sites only after reading one
update_settings and toggle_cache accept site: "all" or a list of handles. Each site validates against its own schema and answers in its own row, so a module missing on one site fails that row and the others still apply. Read one site first, then apply.
Reference
| Discover | list_modules (read): Free and Pro modules, settings schema, status, per site |
|---|---|
| Read settings | get_settings (read): argument module; credential fields masked |
| Change settings | update_settings (write): arguments module and values; validated by the site |
| Bad input | The whole write is refused and nothing is written; the error names the keys and reasons |
| Page cache on or off | toggle_cache (write): argument enabled; cache_enabled in update_settings is refused |
| Blocked by another plugin | toggle_cache returns blocked: true with blocked_reason when another plugin owns the cache drop-in |
| Every site at once | update_settings and toggle_cache accept site: "all" or a list of handles, one result per site |
| Pro modules | A Pro module on a site without an active licence cannot be read or written; the site refuses |
| Credential fields | Refused by default over MCP; set them in the xSpeed dashboard, not through the agent |
| Read-only connection | The connection token with Read-only everywhere on, or a Viewer member's sign-in: update_settings and toggle_cache are refused; list_modules and get_settings still work. An OAuth sign-in gets the scopes the client asks for, read and write by default, clamped to the member's role |
| Confirmation | None on the Hub; the Hub tells the agent to briefly confirm intent for these two, and your client's prompt is the gate |
Rules worth keeping
- Read before you write. Ask for list_modules and get_settings first, so the agent changes real keys with valid values instead of guessing.
- update_settings and toggle_cache change how a live site behaves. They run as soon as your connection allows writes. The Hub tells the agent to briefly confirm intent first, which is guidance to the agent, so your client's approval prompt and a read-only connection (the connection token with Read-only everywhere on, or a Viewer sign-in) are the gates. The switch does not limit an OAuth sign-in.
- For site: "all", the Hub tells the agent to confirm once with "this will touch all N sites", then make one call. The result is per site, and some sites failing is a partial result to report, not a blanket success or failure.
- Do not ask an agent to set credentials such as a Cloudflare token or Redis password. The site refuses those writes by default, and they belong in the xSpeed dashboard.
- If a settings result says a value is saved but inactive on this server, relay that. Do not tell the user the feature is enabled.
Good to know with Hermes Agent
Hermes Agent adds no prompt for a server with the default trust of full, so until you set trust to untrusted, update_settings is only held back by the Hub's request to confirm. With untrusted you will be asked for reads such as get_settings as well. A cron job has nobody watching it: give it a tools include list of read tools, or a read-only connection (the connection token with Read-only everywhere on, or a Viewer sign-in) so the Hub refuses every write, and keep the write connection for conversations where you read the proposal.
More prompts for this job
They work in any client connected to xSpeed Hub.
Use xSpeed Hub to list the modules on shop and tell me which ones are off.
Ask xSpeed Hub for the current minify settings on blog.
With xSpeed Hub, turn on HTML minification on blog, then benchmark the cache and tell me if it helped.
Use xSpeed Hub to turn page caching off on staging while I debug, and tell me when it is off.
Using xSpeed Hub, read the gzip settings on shop first, then enable the same options on every site.
Use xSpeed Hub to set the page cache lifespan on docs to 30 days, and if the site refuses it, tell me why.
Frequently asked questions
Keep going
Tune cache settings with other agents
More with Hermes Agent
Documentation
- How to enable Page Cache
- How to minify CSS and JavaScript
- How to add cache rules and bypasses
- Site MCP tool reference
- How to write prompts for xSpeed Hub
- Hermes Agent + xSpeed
- Every AI agent that works with xSpeed
From the blog