architecture-simplicity

A set of software architecture principles for keeping projects simple and easy to change. It covers when to add abstractions or dependencies, how to divide modules, and how to evolve database schemas safely.

In plain words
What is it for?
Use it when designing modules, reviewing architecture, choosing dependencies, adding abstractions, or changing a database schema.
Why use it?
It helps prevent oversized files, unnecessary libraries, premature abstractions, and database changes that could erase existing data.

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/oleg494/coding-kit/architecture-simplicity
Any agent
npx skills add oleg494/coding-kit --skill architecture-simplicity
Clone the repo
git clone --depth 1 https://github.com/oleg494/coding-kit

Made for: Claude Code, Codex.

Per session 119 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,013 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 $0.00119 $0.01013
Opus 5 $0.00060 $0.00507
Sonnet 5 $0.00024 $0.00203
Haiku 4.5 $0.00012 $0.00101

Measured 2d ago against content hash 10c03e847dbb, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

architecture-simplicity 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.

skills/architecture-simplicity/SKILL.md · 57 lines

How it starts

The opening of the file, as written. The whole thing — 57 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Architecture & simplicity: design principles

1. Simplicity and dependency

  1. YAGNI UNTIL SECOND NEED — an abstraction with one consumer is debt, not architecture. Inline until a second consumer; only then extract. A layer you can remove means the same behavior with less code.
  2. STD LIB / PLATFORM BEFORE DEPENDENCY — a new dependency costs more than 30 lines of your own code (often). Start with stdlib/native; add a dep only if the pain is measurable. moment.js for a single format = no.
  3. SEPARATE MODULES BY CHANGE REASON — generators.py, payments.py, access.py, bot.py — different axes of change. A PDF feature must not touch billing. No 3000-line god file.
  4. SHARED CORE, THIN ADAPTERS — one business logic; Telegram/CLI/desktop is a shell (I/O + auth + UX). A polish bug is fixed in one place, both clients stay fine.
  5. STOP WHEN THE NEXT ABSTRACTION DOESN'T PAY RENT THIS WEEK — an abstraction must pay for itself now, not "someday".

2. Config and evolution

  • CONFIG OUTSIDE REPO, DEFAULTS IN CODE — secrets and ops tuning never in git; safe defaults in code; override via env.
  • SCHEMA EVOLUTION MUST NOT WIPE PROD — deploy must not require DROP TABLE: CREATE IF NOT EXISTS + ALTER ADD COLUMN ignore-if-exists.
  • FEATURE FLAG/ENV DEFAULT > REWRITE — ops tuning via flag/env, not rewriting.
  • DETERMINISTIC REBUILD > STALE CACHE — rebuilding deterministically beats living with a stale cache.

3. Code patterns

  • EXPLICIT SPEND ORDER IN ONE FUNCTION — the debiting order (free→bonus→paid) is one algorithm in one place.
  • FALLBACK CHAIN FOR PROVIDERS — one vendor = SPOF: ordered list; next on timeout/5xx; fail only when all are dead.
  • PURE FUNCTIONS FOR ASSEMBLE/EXPORT; IMPURE AT THE EDGES — assembly/export are pure functions; I/O at the boundaries.
  • MAKE ILLEGAL STATES UNREPRESENTABLE — separate fields over boolean soup: status: active|finished instead of flags.
  • COMMENTS EXPLAIN WHY AND CEILING — not what the line does, but why and what ceiling.
  • DELETE DEAD CODE; DON'T COMMENT IT OUT FOREVER — dead code gets removed.
  • NAMING: VERBS THAT MEAN $ — charge_seconds, apply_referral, can_afford — verbs with money semantics.
  • FLOAT MONEY IS EVIL LONG-TERM — money is not float; minutes are fine if consistent + tested.

Read the full file on GitHub · 57 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. 2d ago First seen · 57 lines · 119 tokens per session scan A 10c03e847dbb

Subscribe to this mod's changes

architecture-simplicity is a skill published in the GitHub repository oleg494/coding-kit (1 stars, last pushed 2d ago), licensed MIT. It adds 119 tokens to every session and 1,013 once invoked, about $0.0006 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 2026-08-31.

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