Borrowing it
Nothing to install: this file belongs to bgigurtsis/aegis-mcp. 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/bgigurtsis/aegis-mcp/main/CLAUDE.mdgit clone --depth 1 https://github.com/bgigurtsis/aegis-mcpWrote 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/bgigurtsis/aegis-mcp/claude-md)<a href="https://agentmods.dev/instructions/bgigurtsis/aegis-mcp/claude-md"><img src="https://agentmods.dev/badge/instructions/bgigurtsis/aegis-mcp/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/bgigurtsis/aegis-mcp/claude-md"><img src="https://agentmods.dev/badge/instructions/bgigurtsis/aegis-mcp/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 | $0.01098 | $0.01098 |
| Opus 5 | $0.00549 | $0.00549 |
| Sonnet 5 | $0.00220 | $0.00220 |
| Haiku 4.5 | $0.00110 | $0.00110 |
Grade A, and why
aegis-mcp 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 9d 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 — 98 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Aegis MCP -- Developer Instructions
Aegis is a deterministic MCP server that maps a project's threat model (encoded in security-context.yaml) to actionable coding requirements for AI agents. No LLM on the hot path; aegis_assess is a structured lookup against the schema.
Architecture
| File | Role |
|---|---|
src/aegis/server.py |
MCP server entrypoint. Defines tools (aegis_assess, aegis_validate, aegis_review) and resource aegis://summary. Loads and validates security context at startup. |
src/aegis/engine.py |
Deterministic assess engine. Matches input params against the context, collects requirements from trust boundaries and data classifications, filters patterns via when clauses, merges with conflict detection. |
src/aegis/validation.py |
JSON Schema (Draft 2020-12) plus normative contract validation. YAML line map for error line numbers. |
src/aegis/review.py |
Post-generation completeness checker that verifies requirement-to-implementation mappings from agents. |
src/aegis/setup.py |
Interactive setup workflow for aegis setup (context discovery/generation guidance, validation loop, IDE wiring, template installation). |
src/aegis/cli.py |
Unified aegis CLI dispatcher (setup, validate, help, about). |
catalogs/security-patterns.yaml |
Comprehensive vulnerability pattern catalog (traditional + LLM code-gen patterns) used as reference input for LLM-assisted security-context generation. |
Key Design Decisions
- No LLM on hot path.
aegis_assessis pure structured lookup; zero token cost per query. - Deterministic semantics. Matching is exact string equality (after trim), case-sensitive. Canonical IDs from the schema.
- IDs: All canonical IDs (trust boundaries, data classifications, patterns) must be kebab-case and unique.
- Precedence when the same requirement appears from multiple sources:
trust_boundary>data_classification> approved/anti-pattern defaults. Conflicts are surfaced inconflicts[], not by failing the request. - Normative contract: Root must have
version,trust_boundaries,data_classifications,approved_patterns,anti_patterns. Unknownboundary_crossingsetsno_match=trueand adds a warning; unknowndata_types/servicesare noted inwarnings[]; unknownactionvalues return warnings with known action IDs.
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.
- 9d ago First seen · 98 lines · 1,098 tokens per session scan A 7cb196988619
aegis-mcp CLAUDE.md is an instructions file published in the GitHub repository bgigurtsis/aegis-mcp (0 stars, last pushed 5mo ago), licensed MIT. It adds 1,098 tokens to every session, about $0.0055 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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