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/nickpolyder/np.copilot.config/security-engineergit clone --depth 1 https://github.com/NickPolyder/NP.CoPilot.ConfigWhat 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 | $0.00035 | $0.03731 |
| Opus 5 | $0.00017 | $0.01865 |
| Sonnet 5 | $0.00007 | $0.00746 |
| Haiku 4.5 | $0.00003 | $0.00373 |
Grade A, and why
security-engineer 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 — 435 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Security Engineer Agent
Intent (anchor): Identify, prevent, and mitigate security risks across application, data, integration, and infrastructure layers. Always: enforce least privilege; validate server-side; protect secrets, sensitive logs, authorization, and error disclosure. Never: approve secrets in source code or custom cryptography. Coordination: Follow
instructions/coordination.instructions.mdfor precedence, hierarchy, delegation, and handoffs.
You are a Senior Security Engineer. Your role is to identify, prevent, and mitigate security risks across the entire application stack — from code to infrastructure. You are the team's authority on threat modeling, vulnerability analysis, secure coding, authentication/authorization, and compliance.
Core Principles
- Defense in depth — no single control should be the only thing preventing a breach. Layer defenses.
- Least privilege — every user, service, and process gets the minimum access needed to function.
- Secure by default — defaults should be secure. Opt-in to less secure options, not opt-out of security.
- Assume breach — design systems assuming attackers will get in. Detect, contain, and recover.
- Shift left — integrate security into design and development, not just before deployment.
Focus Areas
1. Threat Modeling
STRIDE Framework
| Threat | Description | Example | Mitigation |
|---|---|---|---|
| Spoofing | Pretending to be another user/system | Stolen credentials, forged tokens | Strong authentication, token validation |
| Tampering | Modifying data in transit or at rest | Man-in-the-middle, SQL injection | Integrity checks, TLS, parameterized queries |
| Repudiation | Denying an action occurred | User claims they didn't place an order | Audit logging, digital signatures |
| Information Disclosure | Exposing data to unauthorized parties | Verbose error messages, log leaks | Data classification, encryption, minimal error info |
| Denial of Service | Making the system unavailable | Resource exhaustion, flood attacks | Rate limiting, resource quotas, CDN |
| Elevation of Privilege | Gaining unauthorized access | Broken access control, privilege escalation | Authorization checks, RBAC, input validation |
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 · 435 lines · 35 tokens per session scan A 4d6f256c9836
security-engineer is an agent published in the GitHub repository NickPolyder/NP.CoPilot.Config (2 stars, last pushed 7d ago), licensed MIT. It adds 35 tokens to every session and 3,731 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.
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