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/el-feo/ai-context/fowlernpx skills add el-feo/ai-context --skill fowlergit clone --depth 1 https://github.com/el-feo/ai-contextWrote this? Show the measurements
A badge for your README with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them.
[](https://agentmods.dev/skills/el-feo/ai-context/fowler)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 | $0.00228 | $0.01689 |
| Opus 5 | $0.00114 | $0.00844 |
| Sonnet 5 | $0.00046 | $0.00338 |
| Haiku 4.5 | $0.00023 | $0.00169 |
Grade A, and why
fowler 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 3d 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.
How it starts
The opening of the file, as written. The whole thing — 117 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Refactoring — the Fowler Catalog
Channel Martin Fowler's discipline of refactoring: improving the internal structure of code without changing its observable behavior, as a sequence of small, safe, individually testable steps. The catalog names and mechanics come from Refactoring (2nd edition); the discipline applies to any language, not just the book's JavaScript.
The prime rule
Refactoring is not rewriting. Every change must preserve behavior, and the code must pass its tests between steps. If there are no tests, that's the first smell to fix — build a safety net before restructuring (see references/principles.md).
Wear one hat at a time: either you are adding function (changing behavior) or refactoring (changing structure). Never both in the same step, and say which hat you're wearing.
Modes
Detect what the user needs and respond in that mode:
| User intent | Mode | Read first |
|---|---|---|
| "What's wrong with this code?" / review for smells | DIAGNOSE | references/smells.md |
| "Refactor this" / apply a named refactoring | REFACTOR | The catalog file for each refactoring you apply (see index below) |
| "When should I use X vs Y?" / explain a smell or technique | ADVISE | The relevant catalog file, plus references/principles.md for questions of when/whether to refactor |
Always read the matching reference file before producing the substantive response — the mechanics matter, and improvising them loses the safety of the small-step discipline.
DIAGNOSE — smell review
- Read the code. Identify smells by their catalog names (Long Function, Data Clumps, Feature Envy, Shotgun Surgery…), citing the specific lines that smell.
- For each smell, prescribe the refactoring(s) that cure it, using catalog names.
- Rank by payoff: which refactoring would most improve the code's ability to change? Lead with that.
- Don't prescribe what you can't justify — a smell is a prompt to consider refactoring, not a mandate. Say when the code is fine as it is.
What ships with it
9 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.
- 3d ago First seen · 117 lines · 228 tokens per session scan A cc2ae17e8b11
fowler is a skill published in the GitHub repository el-feo/ai-context (12 stars, last pushed 1mo ago), licensed MIT. It adds 228 tokens to every session and 1,689 once invoked, about $0.0011 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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