old-coder
Evidence-first development — surround the implementation with an executable spec and a gauntlet of constraints (tests, types, coverage, mutation) so line-by-line review becomes optional. Use when the user explicitly asks for high-assurance or evidence-first work ("reliable", "TDD", "prove it works", "I won't read the code"), or when the change touches high-stakes domains (money, auth, data loss, concurrency, public API). For routine changes where the user just wants normal tests, write good tests directly instead of invoking this loop.
npx skills add AmazingAng/old-coder --skill old-coder --agent claude-code
Same command for any agent — swap --agent for codex, cursor, copilot.
Weekly change comes from our own snapshots, not the repository page — it measures attention, not adoption.
# Old Coder: Reliable Coding Under Constraint and Test The human will NOT read your implementation. Their confidence comes entirely from two artifacts you produce: (1) an **executable specification** they approve before you write code, and (2) an **evidence report** proving the code ran the gauntlet. Your job is to make those two artifacts trustworthy enough that line-by-line review becomes optional within the spec's boundaries. This inverts the normal review model: **trust moves from inspection to constraints.** Be honest about what that buys: the gauntlet proves the code satisfies every constraint the spec expresses — it cannot prove the spec expresses everything that matters. That is exactly why the human approves the SPEC (the one artifact that breaks the everything-authored-by-the-same-agent correlation), and why EVIDENCE reports layered, auditable confidence, never absolute proof. Every shortcut you take against the gauntlet destroys the only basis of trust. ## The Loop ``` SPEC → (human approves spec, not code) → RED → GREEN → REFACTOR → GAUNTLET → EVIDENCE ↑_____________________| repeat per behavior ``` ### 1. SPEC — the only thing the human reads before code Turn the reque
- The Loop
- 1. SPEC — the only thing the human reads before code
- 2. RED — prove each test can fail
- 3. GREEN — minimal implementation
- 4. REFACTOR — clean up under green, assertions frozen
- 5. GAUNTLET — the constraint stack
- 6. EVIDENCE — the only thing the human reads after code
- Anti-Gaming Rules (absolute)
- Calibration
- Setup
What does the old-coder skill do?
Evidence-first development — surround the implementation with an executable spec and a gauntlet of constraints (tests, types, coverage, mutation) so line-by-line review becomes optional. Use when the user explicitly asks for high-assurance or evidence-first work ("reliable", "TDD", "prove it works", "I won't read the code"), or when the change touches high-stakes domains (money, auth, data loss, concurrency, public API). For routine changes where the user just wants normal tests, write good tests directly instead of invoking this loop.
How do I install it?
Run `npx skills add AmazingAng/old-coder --skill old-coder --agent claude-code` — it drops the skill into your project so the agent can pick it up. Swap the --agent value for codex, cursor or copilot if you use one of those.
Where does this skill come from?
From AmazingAng/old-coder, a repository with 294 stars. We read it straight from the repository tree rather than a submitted listing, so what you see here is what is actually published.
Is a popular skill a good skill?
Not necessarily. Stars measure attention, not adoption — a repository can trend for a week and be abandoned. That is why we show the weekly change from our own snapshots next to the total, instead of a single flattering number.