zero-defect

A precision checklist for high-risk software work, such as production deployments, security-sensitive code, and financial calculations. It emphasizes reading before changes, verifying results, making focused edits, and stating uncertainty clearly.

In plain words
What is it for?
Use it to guide careful reviews, changes, calculations, and deployment work where accuracy and verification matter most.
Why use it?
It reduces mistakes when an incorrect assumption or unverified change could have serious consequences.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/sharpdeveye/maestro/zero-defect
Any agent
npx skills add sharpdeveye/maestro --skill zero-defect
Clone the repo
git clone --depth 1 https://github.com/sharpdeveye/maestro

Made for: Claude Code, Codex.

Per session 33 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 925 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00033 $0.00925
Opus 5 $0.00016 $0.00463
Sonnet 5 $0.00007 $0.00185
Haiku 4.5 $0.00003 $0.00093

Measured yesterday against content hash 49023ea5fd9d, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

zero-defect scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

source/skills/zero-defect/SKILL.md · 84 lines

How it starts

The opening of the file, as written. The whole thing — 84 lines — stays where its author put it; the contents beside it link to each section on GitHub.

MANDATORY PREPARATION

Invoke /agent-workflow — it contains workflow principles, anti-patterns, and the Context Gathering Protocol. Follow the protocol before proceeding — if no workflow context exists yet, you MUST run /teach-maestro first.


Activate maximum precision mode for the current session. This command establishes execution-time discipline — not for the workflow design, but for how the agent itself operates. Every response, every code change, every claim must pass the zero-defect gate.

This is model-agnostic. It works with Claude, Gemini, GPT, Codex, or any AI agent.

The 8 Precision Rules

Follow these for the entire session after this command is invoked:

# Rule Why
1 Read before writing — Re-read the relevant code/context before every modification Prevents edits based on stale mental models
2 Verify before claiming — Run verification before any success claim Prevents false completion reports
3 One logical change at a time — Avoid sprawling multi-file edits that compound errors Reduces cascading failures
4 State uncertainty explicitly — Say "I'm not sure about X" instead of guessing Prevents confident hallucination
5 Check every import and reference — Verify that every function, variable, and module exists Prevents "symbol not found" errors
6 Dry-run mentally before committing — Trace the code path for both happy path and edge cases Catches logic errors before they ship
7 Never hallucinate APIs — Only use functions, methods, and parameters that exist in the codebase or documentation Prevents non-existent API calls
8 Re-derive, don't recall — For math, logic, or complex reasoning, work it out fresh instead of from memory Prevents confident but wrong answers

The Pre-Commit Gate

Before claiming ANY work is complete, pass every item:

  • Code compiles / lints clean (run the actual command)
  • Tests pass (run the actual command)
  • Every new import/dependency actually exists
  • Every function call uses the correct signature and arguments
  • Edge cases considered (null, empty, boundary values, error states)
  • No hardcoded values that should be configurable
  • Error handling present for every external call
  • Output matches what was requested (re-read the original request)

Read the full file on GitHub · 84 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 84 lines · 33 tokens per session scan A 49023ea5fd9d

Subscribe to this mod's changes

zero-defect is a skill published in the GitHub repository sharpdeveye/maestro (415 stars, last pushed 4mo ago), licensed MIT. It adds 33 tokens to every session and 925 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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