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/fellipeutaka/leon/solidnpx skills add fellipeutaka/leon --skill solidgit clone --depth 1 https://github.com/fellipeutaka/leonWhat 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 | $0.00065 | $0.00933 |
| Opus 5 | $0.00032 | $0.00466 |
| Sonnet 5 | $0.00013 | $0.00187 |
| Haiku 4.5 | $0.00006 | $0.00093 |
Grade A, and why
solid 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.
How it starts
The opening of the file, as written. The whole thing — 95 lines — stays where its author put it; the contents beside it link to each section on GitHub.
SOLID Principles
Five principles for building software that is easy to understand, extend, and maintain. They reduce coupling, increase cohesion, and make code testable.
When to Apply
Reference these principles when:
- Designing new classes, modules, or interfaces
- Refactoring code with too many responsibilities
- Reviewing PRs for architectural concerns
- Breaking apart god objects or fat interfaces
- Deciding where to draw module boundaries
- Making code more testable
Quick Reference
| Principle | One-Liner | Red Flag |
|---|---|---|
| SRP | One reason to change | "This class handles X and Y and Z" |
| OCP | Add, don't modify | Growing if/else or switch chains for types |
| LSP | Subtypes are substitutable | Type-checking or special-casing in calling code |
| ISP | Small, focused interfaces | Empty method implementations or throw new Error("Not implemented") |
| DIP | Depend on abstractions | new ConcreteClass() inside business logic |
See references/PRINCIPLES.md for detailed explanations and TypeScript examples.
Detection Checklist
Ask these questions for every class and module:
| Question | Violated Principle |
|---|---|
| Does this class have multiple reasons to change? | SRP |
| Do I need to modify existing code to add a new variant? | OCP |
| Does calling code need type-checks or special cases for subtypes? | LSP |
| Are implementors forced to stub out unused methods? | ISP |
| Does high-level logic directly instantiate infrastructure? | DIP |
Applying SOLID at Different Scales
| Scale | SRP | OCP | LSP | ISP | DIP |
|---|---|---|---|---|---|
| Function | Does one thing | — | — | — | Takes abstractions as params |
| Class | One reason to change | Extend via composition | Subtypes honor contracts | Implements only what it uses | Constructor injection |
| Module | One bounded context | Plugin architecture | Interchangeable implementations | Thin public API | Depends inward |
| Service | Single domain | New features = new services | API contract stability | Minimal API surface | Abstractions at boundaries |
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.
- 2d ago First seen · 95 lines · 65 tokens per session scan A 98f1664756d6
solid is a skill published in the GitHub repository fellipeutaka/leon (5 stars, last pushed 4d ago), licensed MIT. It adds 65 tokens to every session and 933 once invoked, about $0.0003 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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