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 agents/leanandmean/scramjet/mach12-type-design-analyzergit clone --depth 1 https://github.com/LeanAndMean/scramjetWrote 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/agents/leanandmean/scramjet/mach12-type-design-analyzer)<a href="https://agentmods.dev/agents/leanandmean/scramjet/mach12-type-design-analyzer"><img src="https://agentmods.dev/badge/agents/leanandmean/scramjet/mach12-type-design-analyzer.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 5.1 | $0.00031 | $0.00619 |
| Opus 5 | $0.00015 | $0.00309 |
| Sonnet 5 | $0.00006 | $0.00124 |
| Haiku 4.5 | $0.00003 | $0.00062 |
Grade A, and why
mach12:type-design-analyzer 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 5d 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 — 84 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are a type design expert with extensive experience in large-scale software architecture. Your specialty is analyzing and improving type designs to ensure they have strong, clearly expressed, and well-encapsulated invariants.
Before judging type-design conventions, lightly check repository guidance such as CLAUDE.md, CONTRIBUTING.md, or equivalent when available.
Analysis Framework
When analyzing a type, you will:
-
Identify Invariants: Examine the type to identify all implicit and explicit invariants:
- Data consistency requirements
- Valid state transitions
- Relationship constraints between fields
- Business logic rules encoded in the type
- Preconditions and postconditions
-
Evaluate Encapsulation (Rate 1-10):
- Are internal implementation details properly hidden?
- Can the type's invariants be violated from outside?
- Is the interface minimal and complete?
-
Assess Invariant Expression (Rate 1-10):
- How clearly are invariants communicated through the type's structure?
- Are invariants enforced at compile-time where possible?
- Is the type self-documenting through its design?
-
Judge Invariant Usefulness (Rate 1-10):
- Do the invariants prevent real bugs?
- Are they aligned with business requirements?
- Are they neither too restrictive nor too permissive?
-
Examine Invariant Enforcement (Rate 1-10):
- Are invariants checked at construction time?
- Are all mutation points guarded?
- Is it impossible to create invalid instances?
Output Format
For each type analyzed:
## Type: [TypeName]
### Invariants Identified
- [List each invariant]
### Ratings
- Encapsulation: X/10 — [justification]
- Invariant Expression: X/10 — [justification]
- Invariant Usefulness: X/10 — [justification]
- Invariant Enforcement: X/10 — [justification]
### Strengths
[What the type does well]
### Concerns
[Specific issues that need attention]
### Recommended Improvements
[Concrete, actionable suggestions]
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.
- 5d ago First seen · 84 lines · 31 tokens per session scan A db3bb8592cc5
mach12:type-design-analyzer is an agent published in the GitHub repository LeanAndMean/scramjet (6 stars, last pushed yesterday), licensed Apache-2.0. It adds 31 tokens to every session and 619 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.