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 skills add StChiotis/Library-First-Engineering --skill lfe-extract-domaingit clone --depth 1 https://github.com/StChiotis/Library-First-EngineeringWrote 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/stchiotis/library-first-engineering/lfe-extract-domain)<a href="https://agentmods.dev/skills/stchiotis/library-first-engineering/lfe-extract-domain"><img src="https://agentmods.dev/badge/skills/stchiotis/library-first-engineering/lfe-extract-domain.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 | $0.00040 | $0.00438 |
| Opus 5 | $0.00020 | $0.00219 |
| Sonnet 5 | $0.00008 | $0.00088 |
| Haiku 4.5 | $0.00004 | $0.00044 |
Grade A, and why
lfe-extract-domain 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 7d 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
LFE Domain Extraction (Day 0)
Position in Pipeline
- Phase: Any (Failure Recovery)
- Persona: Architect
- Trigger: Called when any persona encounters an undocumented "Black Box" in the code, or at project initialization
- Output:
.docs/domain/domain-knowledge.md+CONTEXT.md
Mission
Extract the project's core logic, math, and terminology from the founder's mind and formalize it into the Library System.
Workflow
- The Core Entity: Ask "What is the single most important noun in this project? What is its exact definition?"
- The Golden Logic: Ask "What is the 'Golden Rule' or primary calculation that this project performs? Walk me through the logic step-by-step."
- The Constraints: Ask "What are the project's absolute hard constraints (legal, safety, or architectural) — the rules that must always hold?"
- The Vocabulary: Identify synonyms or ambiguous terms used during the interview and map them to canonical terms.
Output
Produce a draft for:
.docs/domain/domain-knowledge.mdCONTEXT.md— using the format defined in CONTEXT-FORMAT.md
Rules
- Follow the
CONTEXT-FORMAT.mdstandard for all glossary entries (one-sentence definitions, Avoid aliases, relationships, example dialogue). - If
CONTEXT.mdalready exists, merge new terms into it rather than overwriting. - If an ADR is warranted by a decision made during extraction, use the format in ADR-FORMAT.md.
- After extraction, update
pipeline_status.mdto reflect the new domain knowledge.
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.
- 7d ago First seen · 33 lines · 40 tokens per session scan A 302aedf5d35d
lfe-extract-domain is a skill published in the GitHub repository StChiotis/Library-First-Engineering (43 stars, last pushed 1mo ago), licensed MIT. It adds 40 tokens to every session and 438 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 2026-08-30.
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