What is mcpkernel policy-writing.instructions.md?

A guide for writing YAML policy files that decide whether tool actions are allowed, denied or recorded for review. It also describes optional links to OWASP ASI, a security-risk classification system for agentic applications.

Use it to define tool-specific rules, match argument values with conditions, document security decisions and test policies with the project’s policy tests.

It gives policy files a consistent structure and makes rules easier to test, review and connect to security reporting.

How piyushptiwari1/mcpkernel configures GitHub Copilot

Reuse

Borrowing it

Nothing to install: this file belongs to piyushptiwari1/mcpkernel. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/piyushptiwari1/mcpkernel/main/.github/instructions/policy-writing.instructions.md

Clone the repo

git clone --depth 1 https://github.com/piyushptiwari1/mcpkernel

Made for: GitHub Copilot.

Wrote 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.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/piyushptiwari1/mcpkernel/policy-writing.svg)](https://agentmods.dev/instructions/piyushptiwari1/mcpkernel/policy-writing)

Your own site

<a href="https://agentmods.dev/instructions/piyushptiwari1/mcpkernel/policy-writing"><img src="https://agentmods.dev/badge/instructions/piyushptiwari1/mcpkernel/policy-writing.svg" alt="Measured on agentmods" height="20"></a>

Per session 220 This file is loaded in full into every session.

When invoked 220 The same file — it is already loaded in full.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

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	$0.00220	$0.00220
Opus 5	$0.00110	$0.00110
Sonnet 5	$0.00044	$0.00044
Haiku 4.5	$0.00022	$0.00022

Measured 6d ago against content hash 0031a95bf12f, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

mcpkernel policy-writing.instructions.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 6d 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.

.github/instructions/policy-writing.instructions.md · 28 lines

What it actually says

MCPKernel Policy Writing Guide

Policy Structure

version: "1.0"
rules:
  - id: "rule-unique-id"
    description: "What this rule does"
    tool: "tool_name"         # or "*" for all tools
    action: "allow|deny|audit"
    conditions:
      - field: "argument_name"
        operator: "equals|contains|matches|not_contains"
        value: "match_value"
    owasp_asi: "ASI-XX"      # Optional OWASP mapping

Best Practices

Use specific tool names over wildcards when possible
Always include description for audit trail clarity
Map rules to OWASP ASI categories for compliance reporting
Test policies with: python -m pytest tests/test_policy.py -v

Changes

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.

6d ago First seen · 28 lines · 220 tokens per session scan A 0031a95bf12f

Subscribe to this mod's changes

mcpkernel policy-writing.instructions.md is an instructions file published in the GitHub repository piyushptiwari1/mcpkernel (2 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 220 tokens to every session, about $0.0011 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.

Security a2a agent-security ai-agent ai-security audit-logging deterministic-execution

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mcpkernel: Instructions file for GitHub Copilot