A skill is how I teach Claude a corner of my world. Not a smarter model, just a folder of knowledge and instructions that Claude loads the moment it becomes relevant.
Over the last few months I have written a couple of dozen of them, each one an expert in one part of my work. Here are the ones that run the business, keep the servers alive, hunt for deals and handle the occasional specialist job.
The ones that run the company online
My website expert knows lemontreecloud.com inside out: every page and its two languages, the rule that the contact form must create a CRM lead and never a plain email, and how the mail server and the certificates are wired together. It is, in fact, the very skill writing this post.
Then there is Maria, my AI phone agent, split across two skills. One holds her technical stack: a SIP line feeding a self hosted media server, live transcription, a synthetic voice and the model behind her answers. The other is her business brain: who she is, the catalogue of services she can pitch, when to stop and escalate a call to me on Telegram, and how she writes every conversation into the CRM as a lead.
A development co-pilot quietly logs every coding session into a task in my Odoo, so there is always a written trail of what was done and why. And a small business skill holds the high level map of my two ventures, the telecom project platform and the open source training arm.
The ones that keep the lights on
My system administration skill is my hands on the machines: it connects over SSH to my Proxmox cluster and manages containers, ZFS pools, disks, networks, DNS and the mail server. When something breaks at three in the morning, this is the knowledge that fixes it.
Next to it, a backup custodian watches over every copy across the home cluster, the dedicated backup server and the two machines living at OVH, and complains loudly the day one of them falls behind.
The ones that hunt for deals
One skill hunts prices for new products across Amazon, PcComponentes and AliExpress, scoring each listing and dropping the results into Odoo. Its twin does the same for the second hand market, sweeping Wallapop, Milanuncios, eBay and Cash Converters in search of a bargain.
The specialists
A few skills exist for a single job and do it deeply. One reads an architect's CAD drawing and builds a complete Spanish telecom infrastructure project straight from the plan. Another is a consultant for converting a combustion car into an electric one and steering it through Spanish vehicle homologation.
A legal assistant drafts the first version of Spanish court filings for a law firm, always for a human lawyer to review and never inventing facts or citations. And a last one holds the knowledge of a small Mars rover robot running on a Raspberry Pi, because not everything has to be about work.
The pattern underneath
None of these is a bigger or a special AI. They are all the same Claude, reading my notes. The real work was never the prompting; it was writing down what I know, once, so that it never has to be explained again.