Borrowing it
Nothing to install: this file belongs to Sceptre/sceptre-mcp-server. 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/Sceptre/sceptre-mcp-server/main/.kiro/steering/security.mdgit clone --depth 1 https://github.com/Sceptre/sceptre-mcp-serverWrote 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/sceptre/sceptre-mcp-server/security)<a href="https://agentmods.dev/instructions/sceptre/sceptre-mcp-server/security"><img src="https://agentmods.dev/badge/instructions/sceptre/sceptre-mcp-server/security/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/sceptre/sceptre-mcp-server/security"><img src="https://agentmods.dev/badge/instructions/sceptre/sceptre-mcp-server/security.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 | $0.00359 | $0.00359 |
| Opus 5 | $0.00179 | $0.00179 |
| Sonnet 5 | $0.00072 | $0.00072 |
| Haiku 4.5 | $0.00036 | $0.00036 |
Grade A, and why
sceptre-mcp-server security.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 4d 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.
What it actually says
Security Guidelines
Mandatory Checks Before Any Commit
- No hardcoded secrets (AWS keys, passwords, tokens)
- All tool inputs validated (path traversal, null bytes, absolute paths)
- Error messages don't leak file system paths or stack traces to the agent
- No sensitive data in logs (AWS credentials, account IDs)
Input Validation
This is an MCP server that accepts tool parameters from AI agents. Validate at the boundary:
- Reject path traversal (
..) instack_pathparameters - Reject absolute paths — only relative paths within the Sceptre project
- Reject null bytes in string parameters
- Validate
sceptre_project_direxists and containsconfig/
AWS Credential Handling
- NEVER hardcode AWS credentials in source code
- Use environment variables (
AWS_PROFILE,AWS_DEFAULT_REGION) or IAM roles - Don't log AWS credentials, account IDs, or ARNs
- Credentials flow through Sceptre's standard AWS credential chain
Dependency Security
- Keep dependencies updated regularly
- Run security audits (
poetry run pip-audit) - Review third-party packages before adding
- Commit
poetry.lockfor reproducible builds
Dangerous Patterns to Flag
| Pattern | Severity | Fix |
|---|---|---|
| Hardcoded AWS keys | CRITICAL | Use environment variables |
Unvalidated stack_path |
HIGH | Use _validate_stack_path() |
eval() / exec() with tool input |
CRITICAL | Never use with external data |
| Logging credentials or ARNs | MEDIUM | Sanitize log output |
Bare except: swallowing errors |
MEDIUM | Use specific exception types |
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.
- 4d ago First seen · 45 lines · 359 tokens per session scan A 949dc5929abf
sceptre-mcp-server security.md is an instructions file published in the GitHub repository Sceptre/sceptre-mcp-server (0 stars, last pushed 5d ago), licensed Apache-2.0. It adds 359 tokens to every session, about $0.0018 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 2026-09-08.
Other instructions, from other repositories
spec-kit AGENTS.md
AGENTS.md instructions for github/spec-kit, covering agents.md, about spec kit and specify, quickstart — add a new integration in 5 steps, integration architecture and integrationmanifest — file tracking.
next.js AGENTS.md
AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
codex AGENTS.md
AGENTS.md instructions for openai/codex, covering rust/codex-rs, the codex-core crate, code review rules, crate api surface and model visible context.
vscode buildNext.instructions.md
Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
langchain AGENTS.md
AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, applying the notice (cutover) and fallback chain (never fail the build).