guard

An internal pre-edit check that limits file changes to an approved workspace scope. It can activate, check, show, or clear that scope.

In plain words
What is it for?
Use it before editing files to activate a workspace, verify a target file is allowed, inspect the current scope, or deactivate the check.
Why use it?
It blocks edits when no workspace is active or when a file falls outside the permitted area.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/fall-out-bug/sdp/guard
Any agent
npx skills add fall-out-bug/sdp --skill guard
Clone the repo
git clone --depth 1 https://github.com/fall-out-bug/sdp

Made for: Claude Code, Codex.

Per session 12 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 134 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00012 $0.00134
Opus 5 $0.00006 $0.00067
Sonnet 5 $0.00002 $0.00027
Haiku 4.5 $0.00001 $0.00013

Measured 2d ago against content hash 802d0f79cf7c, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

guard 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.

prompts/skills/guard/SKILL.md · 28 lines

What it actually says

@guard (INTERNAL)

Pre-edit gate. Called automatically before file edits. Enforce edits within active WS scope.

Commands

sdp guard activate <ws-id>   # Set scope
sdp guard check <file>      # Verify file in scope
sdp guard status            # Show current
sdp guard deactivate        # Clear

Flow

  1. Active WS? No → BLOCK
  2. File in scope? No → BLOCK
  3. Allow edit

Output

ALLOWED or BLOCKED with scope details.

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. 2d ago First seen · 28 lines · 12 tokens per session scan A 802d0f79cf7c

Subscribe to this mod's changes

guard is a skill published in the GitHub repository fall-out-bug/sdp (19 stars, last pushed 2mo ago), licensed MIT. It adds 12 tokens to every session and 134 once invoked, about $0.0001 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 2026-08-30.