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.
npx agentmods add skills/codebygarv/ai-skills/legacy-code-refactorernpx skills add codebygarv/Ai-skills --skill legacy-code-refactorergit clone --depth 1 https://github.com/codebygarv/Ai-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/codebygarv/ai-skills/legacy-code-refactorer)<a href="https://agentmods.dev/skills/codebygarv/ai-skills/legacy-code-refactorer"><img src="https://agentmods.dev/badge/skills/codebygarv/ai-skills/legacy-code-refactorer.svg" alt="Measured on agentmods" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00028 | $0.00344 |
| Opus 5 | $0.00014 | $0.00172 |
| Sonnet 5 | $0.00006 | $0.00069 |
| Haiku 4.5 | $0.00003 | $0.00034 |
Grade A, and why
legacy-code-refactorer 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 4d 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.
What it actually says
Purpose
Plan safe, incremental refactorings of complex, untested legacy codebases using proven methodologies (Mikado Method, Characterization Testing, Strangler Fig pattern, Seams) without breaking production behavior.
When to Use
- Refactoring sprawling 3,000-line "God classes" or legacy spaghetti functions.
- Untangling deeply coupled monolithic code with zero existing unit tests.
- Modernizing ancient callback-hell or global-state architectures into clean, testable interfaces.
What to Analyze
- Characterization Tests (Golden Master): Capture existing behavior with black-box snapshot tests before touching code.
- Mikado Graph: Map dependency prerequisites to identify leaf nodes that can be refactored safely first.
- Seam Identification: Find places where behavior can be intercepted and mocked without editing core logic.
- Extract Interface & Dependency Injection: Replace direct static class instantiation with injected interfaces.
- Incremental Verification: Ensure every micro-step leaves the codebase in a releasable, passing state.
Output Format
- Mikado Refactoring Dependency Tree: Step-by-step ordered graph of prerequisite tasks.
- Characterization Test Harness: Safety-net test verifying existing input/output contracts.
- Before / After Code Diffs: Clean step-by-step refactoring transformations.
Avoid
- Attempting a "Big Bang" rewrite from scratch that never reaches production.
- Refactoring internal logic before establishing characterization test safety nets.
What ships with it
2 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.
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.
- 4d ago First seen · 34 lines · 28 tokens per session scan A 09d5f279c16e
legacy-code-refactorer is a skill published in the GitHub repository codebygarv/Ai-skills (24 stars, last pushed 15d ago), licensed MIT. It adds 28 tokens to every session and 344 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
Other skills, from other repositories
bun-api
Bun runtime API reference for TypeScript scripts. Covers Bun.file(), Bun.write(), Bun.$() shell, Bun.spawn(), Bun.Glob, Bun.env, bun:sqlite, Bun.sql() for PostgreSQL/MySQL via DATABASEURL, Bun.s3 for S3-compatible storage, Bun.redis for Redis/Valkey, Bun.Archive for tarballs, Bun.Image image processing, Bun.WebView…
bun-cli
Bun CLI reference for package management, script running, testing, bundling, and compilation. Covers bun install/add/remove/update, bun run, bun test, bun build, bunx, bun patch, bun audit fix, bun dedupe, bun prune, bun why, bun pm, bun repl, bunfig.toml, bun.lock, workspace catalogs, isolated installs and the global…
deps-upgrade
Validate JavaScript/TypeScript dependency upgrades after an interactive or manual update. Establish the real delta from git, detect peer/engine/type conflicts, extract breaking changes, migrations and adoptable features from release notes, assess held-back or seemingly unused packages, and run verification gates.…
git-pr
PR and MR workflows for GitHub (gh) and GitLab (glab). Creation, review comment handling, thread resolution, review state queries, merging, cost-aware bot review rounds (GitHub: Copilot, CodeRabbit), and Copilot code review configuration (rulesets, custom instructions, billing). Use when creating PRs/MRs, addressing…
git-project
GitHub Projects (v2) setup and management via gh CLI + GraphQL: organize a repo's issues into epics with native sub-issues, drive a board Status flow (Todo -> In Progress -> Done), set Project Priority, classify with native issue Types (Task/Bug/Feature) instead of labels, scope work with milestones (incl. resolving…
git-ci
CI/CD status queries for GitHub Actions (gh) and GitLab CI (glab). Check pipeline status, failing jobs, workflow runs, job logs, and merge readiness. Use when checking CI status, debugging build failures, viewing job logs, watching pipeline progress, or configuring gh/glab CI read-only allowlists. Not for PR workflows…