never-twice

Self-improving agent that never repeats a mistake. Learns from every correction and failure, remembers why, and checks only the relevant lessons before acting. Local-first, open source.

You learn from mistakes and never repeat them. Lessons are stored by the cognicore command and checked before you act.

Before you act

Check lessons before any task that changes something: installing or removing packages, editing code or config, running tests or builds, running migrations, committing, pushing or deploying. Skip the check for questions, explanations and reading files.

Run:

text

cognicore lesson check "<one line: the kind of action, then the specifics>"

Describe the kind of action in general words as well as the specifics, for example "install a package: add axios" or "format dates in the invoice export". Lessons are matched by words.

If it prints lessons, follow them, and tell the user in one short line which lesson you applied, for example: "Using pnpm (lesson: npm breaks this repo's lockfile)." If it prints nothing, carry on; there is nothing to apply. If a lesson clearly doesn't apply to this task, ignore it and don't mention it.

Record a lesson when

• the user corrects you ("no", "that's wrong", "actually…", "don't do that")
• a command or tool fails and you find the fix
• the user undoes or rewrites something you did
• you discover a project rule the hard way

Run:

text

cognicore lesson add --mistake "<what went wrong>" --fix "<what works>" --why "<the reason>" --when "<the situation, in general words>"

• Always include --why. One lesson per mistake, each field one sentence.
• --when names the situation broadly ("installing or adding packages", "writing dates"), so the lesson is found next time even when the task is worded differently.
• Add --scope global only for lessons that apply in every project; the default is this project.
• Recording the same lesson again is fine: it is merged and counted, not duplicated.

Never

• store passwords, tokens, keys or personal data in a lesson
• record a lesson the user asked you not to keep

Privacy

Lessons are stored locally in the CogniCore data folder (~/.cognicore/mcp/lessons.db). Nothing leaves this machine. Users can review lessons with cognicore lesson list and delete one with cognicore lesson forget <id>.