The description is the trigger
Somewhere in your team's agent setup there is probably a skill that has never once run, and the reason is a sentence. A skill runs because the agent read its one-line description and judged that it matched the request in front of it. The description isn't documentation for whoever browses the folder. It's the trigger. In our prototype's sample data, a skill described as “Audits expenditure reports for compliance” sat at zero fires for thirty days while people kept asking “Check my expenses.” Same intent, different words, so the skill never loaded.
The mechanism is where agentic software departs from the software most teams have shipped before. In a conventional app, a feature runs because a user clicked the button wired to it. In agentic software, the wiring is made of sentences. A skill, as Anthropic's Agent Skills format (published October 2025) settled it, is a folder with a SKILL.md file at the top: plain-language instructions for how a piece of work should be done, packaged with reference documents, runnable scripts, and templates for the artifacts it produces. The agent scans the descriptions of the skills available to it and loads the one that fits the task. So a skill can be flawless inside and still unreachable, and the fix is an edit to one line.
One request through the trigger loop. The match against the description decides everything downstream, which is why a zero in the fires column points at the wording.
Follow one request through the loop above and the design of a skill library falls out of it. The words a person uses are matched against the words the author wrote. A match fires the skill; a miss produces silence, with no error and no trace. Primer is one of our design-sprint prototypes, built around that loop: screens and sample data you can click through, a prototype rather than a shipped product. First we show the day a skill outgrows its git repo, then the four jobs a library does, then the zero that makes the whole thing measurable.
