The skill contract (every skill obeys it)

Part 1 · PLUGIN STRUCTURE AND ARCHITECTURE · Slide 8 of 60

1. TRIGGER      a /slash verb and plain-language phrases
2. CONTRACT     what goes in, what comes out, what it never does
3. SELF-CHECK   the skill grades its own output before returning
4. FINISH       what it hands to the next skill (chains)
5. EXIT CODES   for scripts: 0 green · 2 usage · 3 not-applicable
                              5 warnings · 6 failures

The harness grades itself against this contract:
`eval` fails any skill missing a part.