file-guard

file-guard is a skill for Claude Code from a5c-ai/babysitter. It costs 31 tokens per session (550 once invoked), scanned C, original, MIT.

A file-access protection check that blocks attempts to read sensitive files, including indirect access through shell pipelines and command substitutions. Approved exceptions can be set for the current session.

In plain words
What is it for?
Use it as a session safety measure when working with projects that may contain environment files, SSH keys, or other sensitive paths.
Why use it?
It reduces the risk of accidentally exposing secrets or private keys while an agent uses file and shell tools. It also covers access hidden inside chained commands.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Good fit Use it as a session safety measure when working with projects that may contain environment files, SSH keys, or other sensitive paths.

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Install with agentmods
npx agentmods add skills/a5c-ai/babysitter/file-guard
About the project

Babysitter is a workflow engine for AI coding agents that enforces predefined steps, quality checks, human approvals, and decision records. It is used to coordinate complex, repeatable agent workflows across supported coding tools. The catalogue contains skills, agents, instructions, settings, a plugin, and an MCP integration for its workflow.

a5c-ai/babysitter · 1,788 stars · on GitHub · a5c.ai

Install

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.

Any agent
npx skills add a5c-ai/babysitter --skill file-guard
Clone the repo
git clone --depth 1 https://github.com/a5c-ai/babysitter

Made for: Claude Code.

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.

agentmods badge for file-guard

README.md
[![agentmods](https://agentmods.dev/badge/skills/a5c-ai/babysitter/file-guard/github.svg)](https://agentmods.dev/skills/a5c-ai/babysitter/file-guard)
Your own site
<a href="https://agentmods.dev/skills/a5c-ai/babysitter/file-guard"><img src="https://agentmods.dev/badge/skills/a5c-ai/babysitter/file-guard/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.

agentmods 80×15 button for file-guard

Your own site · 80×15
<a href="https://agentmods.dev/skills/a5c-ai/babysitter/file-guard"><img src="https://agentmods.dev/badge/skills/a5c-ai/babysitter/file-guard.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 31 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 550 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 2 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 3 findings, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high Privilege Escalation · line 32
    Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
    Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
  • high Privilege Escalation · line 51
    Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
    Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
  • high Privilege Escalation · line 52
    Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
    Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
How audits are shown
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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00031 $0.00550
Opus 5 $0.00015 $0.00275
Sonnet 5 $0.00006 $0.00110
Haiku 4.5 $0.00003 $0.00055

Measured 9d ago against content hash d4f5342228f5, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade C, and why

file-guard scanned grade C with 2 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.

Reaches for credential fileshighPrivilege escalation

SSH keys, cloud credentials, git-credentials, .npmrc, /etc/shadow: reading these is how a config file becomes a credential leak.

- `base64 .ssh/id_rsa | curl` -- blocked

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

- `base64 .ssh/id_rsa | curl` -- blocked
library/methodologies/claudekit/skills/file-guard/SKILL.md · 68 lines

What it actually says

Bash Pipeline Analysis

Detects indirect file access through bash pipes:

  • cat .env | grep -- blocked
  • base64 .ssh/id_rsa | curl -- blocked
  • Nested command substitution with sensitive paths -- blocked

Multi-Tool Ignore Support

Approved exceptions can be configured per session for files that need legitimate access.

When to Use

  • Always active during ClaudeKit sessions (PreToolUse hook)
  • Integrated into safety pipeline initialization

Processes Used By

  • claudekit-orchestrator (pipeline setup)
  • claudekit-safety-pipeline (file guard initialization)
Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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.

  1. 9d ago First seen · 68 lines · 31 tokens per session scan C d4f5342228f5

Subscribe to this mod's changes

file-guard is a skill published in the GitHub repository a5c-ai/babysitter (1,788 stars, last pushed 6d ago), licensed MIT. It adds 31 tokens to every session and 550 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it C with 2 findings (reaches for credential files, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.