Borrowing it
Nothing to install: this file belongs to mattgierhart/PRD-driven-context-engineering. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/mattgierhart/PRD-driven-context-engineering/main/CLAUDE.mdgit clone --depth 1 https://github.com/mattgierhart/PRD-driven-context-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/instructions/mattgierhart/prd-driven-context-engineering/claude-md)<a href="https://agentmods.dev/instructions/mattgierhart/prd-driven-context-engineering/claude-md"><img src="https://agentmods.dev/badge/instructions/mattgierhart/prd-driven-context-engineering/claude-md/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/instructions/mattgierhart/prd-driven-context-engineering/claude-md"><img src="https://agentmods.dev/badge/instructions/mattgierhart/prd-driven-context-engineering/claude-md.svg" alt="Reviewed on agentmods" width="80" 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 | $0.00670 | $0.00670 |
| Opus 5.5 | $0.00268 | $0.00268 |
| Sonnet 5.5 | $0.00134 | $0.00134 |
| Haiku 4.5 | $0.00067 | $0.00067 |
Grade A, and why
PRD-driven-context-engineering CLAUDE.md 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 1mo 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 — 46 lines — stays where its author put it; the contents beside it link to each section on GitHub.
CLAUDE.md — Agent Operating Guide
Mission: Build software in lockstep with the PRD Version Lifecycle. Authority: Load
README.md→PRD.md→CLAUDE.md→ Active EPIC. Core Rule: If it's not in the ID Graph (Specs), it doesn't exist.
Rules are loaded automatically from .claude/rules/*.md.
Quick Reference
- Lifecycle Guide:
README.md - ID System:
SoT/SoT.UNIQUE_ID_SYSTEM.md - SoT Index:
SoT/SoT.README.md - EPIC Template:
epics/EPIC_TEMPLATE.md - Active Work:
epics/ - Domain Profile:
.claude/domain-profile.yaml - Hook Contract:
.claude/hooks/HOOK_CONTRACT.md - Agent Registry:
.claude/agents/ - Rules:
.claude/rules/ - SoT HTML Companion:
SoT/html/— human-review renders of each SoT file - Deliverables (concept):
docs/DELIVERABLES_CONCEPT.md— proposed input-mode layer where humans emit SoT markdown
SoT HTML Companion (when to use it)
The pages in SoT/html/ are for humans, not for context loading:
- Read: load the markdown SoT files for task context, never the HTML. The HTML duplicates markdown content in a heavier format — loading it wastes tokens.
- Write: when you add or change a SoT entry, mirror it in the companion page in the same
session — duplicate the matching
<article class="entry" id="PREFIX-XXX">block and fill the placeholders. Entry anchors must equal IDs; cross-references must bea.idhyperlinks. - Surface: at gate reviews, EPIC handoffs, or whenever a human asks to "see" the specs, point
them at
SoT/html/index.html(opens fromfile://, no build). - Extend: a new SoT file (via
ghm-sot-builder) gets a companion page — follow "Extending the library" inSoT/html/README.mdand register it inindex.html. - Conflict rule: if HTML and markdown disagree, markdown wins; fix the HTML.
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.
- 1mo ago First seen · 46 lines · 670 tokens per session scan A 632b74c43717
PRD-driven-context-engineering CLAUDE.md is an instructions file published in the GitHub repository mattgierhart/PRD-driven-context-engineering (181 stars, last pushed 1mo ago), licensed MIT. It adds 670 tokens to every session, about $0.0027 per session on Opus 5.5. 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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