97-dev

A coding guide based on lessons from the book “97 Things Every Programmer Should Know.” It provides principles for designing, writing, reviewing, testing, and refactoring software.

In plain words
What is it for?
Use it when making design decisions, reviewing code quality, planning tests, improving error handling, or refactoring existing code.
Why use it?
It gives practical guidance for avoiding unnecessary complexity, duplicated knowledge, unclear code, and untracked technical debt.

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/deevsdeevs/agent-system/97-dev
Any agent
npx skills add DeevsDeevs/agent-system --skill 97-dev
Clone the repo
git clone --depth 1 https://github.com/DeevsDeevs/agent-system

Made for: Claude Code, Codex.

Per session 46 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 787 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 $0.00046 $0.00787
Opus 5 $0.00023 $0.00394
Sonnet 5 $0.00009 $0.00157
Haiku 4.5 $0.00005 $0.00079

Measured 2d ago against content hash 25e7f5045d76, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

97-dev 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 2d ago.

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.

97-dev/SKILL.md · 78 lines

How it starts

The opening of the file, as written. The whole thing — 78 lines — stays where its author put it; the contents beside it link to each section on GitHub.

97-dev: Programmer's Wisdom

Distilled principles from 97 Things Every Programmer Should Know. Apply when writing, reviewing, or making design decisions.

Core Philosophy

Code is design. Software development is a creative discipline requiring craftsmanship, not mechanical construction.

The code tells the truth. Documentation lies, comments decay - only executable code reveals actual behavior. Make code self-explanatory.

Care about your code. Excellence stems from attitude, not just knowledge. Craft elegant code that is clearly correct.

Quick Principles

Principle One-liner
Simplicity Remove everything unnecessary; less is more
Boy Scout Leave code cleaner than you found it
DRY Single authoritative representation for each piece of knowledge
SRP One reason to change per class/module/function
Comments Comment only what code cannot say - explain why, not what
Tech debt Pay immediately or track the compounding interest
Testing Non-negotiable professional obligation
Errors Always check, always handle, every time
Next commit Know exactly what you're committing before you start
Users You are not the user - observe, don't assume

Detailed References

Load these when you need deeper guidance on specific topics:

references/simplicity.md

When: Refactoring bloated code, making architectural decisions, deciding what to remove, questioning if features are needed. Covers: Beauty in simplicity, reduction over addition, improving by removing, code as design.

references/quality.md

When: Code review, enforcing standards, improving maintainability, designing APIs and interfaces. Covers: Boy Scout Rule, DRY principle, Single Responsibility, interface design, code as truth.

references/professionalism.md

When: Career decisions, team dynamics, handling pressure, technical debt discussions, attitude check. Covers: Professional responsibility, caring about code, long-term thinking, prudent debt management.

Read the full file on GitHub · 78 lines

Files

What ships with it

7 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 2d ago First seen · 78 lines · 46 tokens per session scan A 25e7f5045d76

Subscribe to this mod's changes

97-dev is a skill published in the GitHub repository DeevsDeevs/agent-system (40 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 46 tokens to every session and 787 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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