improve-codebase-architecture

improve-codebase-architecture is a skill for Claude Code, Codex from andrewsrigom/agent-skills. It costs 41 tokens per session (493 once invoked), scanned A, original, MIT.

A guide to finding architectural problems in an existing codebase and turning them into focused improvement proposals. It looks at module boundaries, coupling, interfaces, and how easily parts can be tested.

In plain words
What is it for?
Use it to find tightly connected modules, poor seams between features, hard-to-test boundaries, deeper module designs, and concrete refactoring candidates.
Why use it?
It helps distinguish a structural problem from a local code-quality issue before anyone starts a broad rewrite.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

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/andrewsrigom/agent-skills/improve-codebase-architecture
Any agent
npx skills add andrewsrigom/agent-skills --skill improve-codebase-architecture
Clone the repo
git clone --depth 1 https://github.com/andrewsrigom/agent-skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

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agentmods badge for improve-codebase-architecture

README.md
[![agentmods](https://agentmods.dev/badge/skills/andrewsrigom/agent-skills/improve-codebase-architecture.svg)](https://agentmods.dev/skills/andrewsrigom/agent-skills/improve-codebase-architecture)
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<a href="https://agentmods.dev/skills/andrewsrigom/agent-skills/improve-codebase-architecture"><img src="https://agentmods.dev/badge/skills/andrewsrigom/agent-skills/improve-codebase-architecture.svg" alt="Measured on agentmods" height="20"></a>
Per session 41 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 493 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 5.1 $0.00041 $0.00493
Opus 5 $0.00020 $0.00246
Sonnet 5 $0.00008 $0.00099
Haiku 4.5 $0.00004 $0.00049

Measured 6d ago against content hash bb4e78f1451a, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

improve-codebase-architecture 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 6d 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.

engineering/improve-codebase-architecture/SKILL.md · 71 lines

How it starts

The opening of the file, as written. The whole thing — 71 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Improve Codebase Architecture

Use this skill when the user wants architectural improvement ideas before touching implementation.

Scope

  • finding shallow or tightly coupled modules
  • identifying poor seams between features
  • spotting places where boundaries are hard to test
  • proposing deeper modules and simpler public interfaces
  • generating concrete architectural refactor candidates

Default path

  1. Explore the codebase like a new contributor would.
  2. Note where understanding one concept requires too much file-hopping.
  3. Find boundaries where interfaces are almost as complex as the internals.
  4. Group friction into architectural candidates instead of isolated complaints.
  5. For each candidate, describe:
    • current friction
    • likely deeper boundary
    • testing impact
    • tradeoffs
  6. Recommend the best candidate to pursue first.

When to deviate

  • Zoom into one subsystem only when one boundary clearly dominates the architectural pain.
  • Recommend no architectural change if the main issue is local implementation quality rather than a bad seam.
  • Escalate to a refactor plan once one candidate is clearly worth pursuing.

Guardrails

  • Do not propose broad rewrites without a specific boundary problem.
  • Favor deeper modules over just moving files around.
  • Focus on seams that improve testability and change safety.
  • Keep recommendations tied to user-facing or developer-facing pain, not aesthetics.

Avoid

  • proposing a rewrite without a concrete boundary failure
  • confusing file shuffling with architecture improvement
  • optimizing for conceptual neatness while ignoring testability or change safety
  • generating a long complaint list without grouping it into candidates

Verification checklist

  • each candidate is tied to a real friction point
  • the stronger boundary is described in terms of what it would hide
  • testability or change-safety impact is explicit
  • tradeoffs are named, not implied
  • one candidate is recommended as the best first move

Read the full file on GitHub · 71 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. 6d ago First seen · 71 lines · 41 tokens per session scan A bb4e78f1451a

Subscribe to this mod's changes

improve-codebase-architecture is a skill published in the GitHub repository andrewsrigom/agent-skills (2 stars, last pushed 5mo ago), licensed MIT. It adds 41 tokens to every session and 493 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 2026-08-31.