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 xD4O/praxis --skill security-reasoninggit clone --depth 1 https://github.com/xD4O/praxisWrote 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/xd4o/praxis/security-reasoning)<a href="https://agentmods.dev/skills/xd4o/praxis/security-reasoning"><img src="https://agentmods.dev/badge/skills/xd4o/praxis/security-reasoning/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/skills/xd4o/praxis/security-reasoning"><img src="https://agentmods.dev/badge/skills/xd4o/praxis/security-reasoning.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 | $0.00083 | $0.00872 |
| Opus 5.5 | $0.00033 | $0.00349 |
| Sonnet 5.5 | $0.00017 | $0.00174 |
| Haiku 4.5 | $0.00008 | $0.00087 |
Grade A, and why
security-reasoning 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 15d 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 — 94 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Security Reasoning Protocol
EXTREMELY_IMPORTANT: This is a MANDATORY protocol, not a suggestion. Follow every step. Do not skip steps. Do not combine steps. Do not summarize. Work through each gate in order.
This task involves a trust boundary. You MUST complete threat analysis before writing or approving security-sensitive code.
STEP 1 — Identify trust boundaries
List every point where data crosses a trust boundary:
- User input entering the system
- Data crossing network boundaries
- Calls between services with different privilege levels
- Data entering or leaving storage
- Interactions with third-party services
For each boundary, name what's on each side and what data crosses.
STEP 2 — STRIDE analysis
For each trust boundary, answer ALL six questions. Do not skip any. Mark each as MITIGATED, NEEDS-MITIGATION, or NOT-APPLICABLE.
S — Spoofing: Can an attacker pretend to be someone else at this boundary? How is identity verified? What happens if verification is bypassed?
T — Tampering: Can data be modified in transit or at rest? Is integrity checked? What happens if data is silently corrupted?
R — Repudiation: Can a user deny they performed an action? Are significant actions audit-logged with tamper-proof timestamps?
I — Information Disclosure: Can sensitive data leak? Is data encrypted in transit (TLS) and at rest? Are error messages sanitized? Do logs accidentally include tokens, passwords, or PII?
D — Denial of Service: Can this boundary be overwhelmed? Is there rate limiting? Resource quotas? Timeout enforcement?
E — Elevation of Privilege: Can a user gain unauthorized access? Is authorization checked at every operation, not just at the entry point? Are permissions enforced server-side, not just client-side?
STEP 3 — Attack surface summary
Produce a table:
| Boundary | Threat | Severity | Mitigation | Status |
|---|---|---|---|---|
| [boundary] | [S/T/R/I/D/E] | [Critical/High/Med/Low] | [what prevents it] | [done/needed] |
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.
- 15d ago First seen · 94 lines · 83 tokens per session scan A 4c7934d73784
security-reasoning is a skill published in the GitHub repository xD4O/praxis (28 stars, last pushed 2mo ago), licensed MIT. It adds 83 tokens to every session and 872 once invoked, about $0.0003 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 2026-10-02.
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