--- description: Write down a procedure worth keeping — a multi-step process, a trap that cost real time, or something that has now come up three times. Use it the moment you finish such a task, while the details are still exact. --- # Record what you just worked out Write a file into `.chamnan/skills/.md`. ## When this is worth doing - A task took several steps that were not obvious, and will come up again - Something failed in a way that was expensive to diagnose - You have now done the same thing a third time - A decision was made whose *reason* will not be visible in the code afterwards ## When it is not Anything a competent reader gets from the code itself. A file that restates what the code says costs tokens on every future session and returns nothing. When in doubt, don't — an over-full skills directory trains the next session to skip the directory. ## Format ```markdown --- description: --- # ## The trap / the task What actually happens, concretely. Name real files, real commands, real error text. ## What to do The steps, in order. ## Why it is like this The reason. This is the part that stops someone "fixing" it back to the broken version. ``` **The `description` line is not optional.** Session start lists every skill by name *and* description; a file with no description shows as a bare filename, and a bare filename is not enough for a future session to decide whether to open it. That is the whole cost of the registry wasted. Write in the language set as `language` in `.chamnan/config.json` (default `en`). These files are re-read on every session, which is why English is the default — but a procedure your team cannot read is worth nothing however cheap it is. Be specific. "Be careful with the cache" is worthless. "`_write_index` is a plain `write_text` with no atomic replace, so two threads writing the same index drop one update and can interleave into invalid JSON, which `_read_index` turns into `[]` — batch such updates into one pass" is worth keeping.