agentic-stack: Skill for Claude Code

.agent/skills/skillforge/SKILL.md

skillforge is a skill for Claude Code, Codex from codejunkie99/agentic-stack. It costs 2 tokens per session (400 once invoked), scanned A, original, Apache-2.0.

A guide for creating and maintaining skills for coding agents. It covers checking for similar skills, writing instructions, registering the new skill, recording the decision, and improving the process after failures.

In plain words
What is it for?
Use it when creating a new skill, deciding what good skill instructions contain, or updating the skill-creation process based on previous results.
Why use it?
It gives a repeatable way to add agent capabilities without creating duplicates or leaving new skills undocumented and unregistered.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

This is codejunkie99/agentic-stack's own configuration. It tells Claude Code and Codex how to work on agentic-stack itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything agentic-stack configures →

About the project

agentic-stack is a portable layer of agent memory, skills, and protocols stored in a .agent/ folder that can be used across multiple coding-agent tools. It is for people who switch between agent harnesses while keeping shared knowledge and monitoring data. The catalogue entries provide skills and rules for this shared agent layer.

codejunkie99/agentic-stack · 2,302 stars · on GitHub

Reuse

Borrowing it

Nothing to install: this file belongs to codejunkie99/agentic-stack. 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/codejunkie99/agentic-stack/master/.agent/skills/skillforge/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/codejunkie99/agentic-stack

Made for: Claude Code, Codex.

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 skillforge

README.md
[![agentmods](https://agentmods.dev/badge/skills/codejunkie99/agentic-stack/skillforge/github.svg)](https://agentmods.dev/skills/codejunkie99/agentic-stack/skillforge)
Your own site
<a href="https://agentmods.dev/skills/codejunkie99/agentic-stack/skillforge"><img src="https://agentmods.dev/badge/skills/codejunkie99/agentic-stack/skillforge/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 skillforge

Your own site · 80×15
<a href="https://agentmods.dev/skills/codejunkie99/agentic-stack/skillforge"><img src="https://agentmods.dev/badge/skills/codejunkie99/agentic-stack/skillforge.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 2 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 400 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 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 Rogue Agent · line 6
    Skill modifies its own code, configuration, or behavior at runtime. Self-modification enables an agent to escalate privileges, disable safety constraints, or install persistent backdoors.
    Fix: Prevent the skill from modifying its own code, SKILL.md, or configuration files. Treat skill files as read-only at runtime.
  • high Rogue Agent · line 19
    Skill modifies its own code, configuration, or behavior at runtime. Self-modification enables an agent to escalate privileges, disable safety constraints, or install persistent backdoors.
    Fix: Prevent the skill from modifying its own code, SKILL.md, or configuration files. Treat skill files as read-only at runtime.
  • high Rogue Agent · line 32
    Skill modifies its own code, configuration, or behavior at runtime. Self-modification enables an agent to escalate privileges, disable safety constraints, or install persistent backdoors.
    Fix: Prevent the skill from modifying its own code, SKILL.md, or configuration files. Treat skill files as read-only at runtime.
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 $0.00002 $0.00400
Opus 5.5 $0.00001 $0.00160
Sonnet 5.5 $0.00000 $0.00080
Haiku 4.5 $0.00000 $0.00040

Measured 1mo ago against content hash 999e4de4c98d, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

skillforge 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 1mo 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.

.agent/skills/skillforge/SKILL.md · 38 lines

What it actually says

Skillforge — the skill that creates skills

When a new capability is needed:

  1. Check for duplicates. Read skills/_index.md. If a similar skill exists, extend it instead of creating a new one.
  2. Check memory. Read memory/semantic/LESSONS.md for related patterns.
  3. Draft the skill. Create skills/<name>/SKILL.md with:
    • YAML frontmatter (name, version, triggers, tools, preconditions, constraints)
    • Plain-language instructions (destinations and fences, not driving directions)
    • A self-rewrite hook at the bottom
  4. Register it. Add an entry to skills/_index.md and append a JSON line to skills/_manifest.jsonl.
  5. Log it. Append a record to memory/semantic/DECISIONS.md explaining why this skill was created.

What good skills look like

  • State the destination ("verify tests pass before commit"), not the exact command sequence.
  • Include 2–3 examples of correct behavior when it clarifies intent.
  • Include 1 example of a failure and what was learned from it.
  • Keep the whole file under 100 lines.

Self-rewrite hook

After every 5 skills created, or on any failed creation:

  1. Read the last 5 skillforge entries from episodic memory.
  2. If better trigger patterns or constraint structures have emerged, update this file and the template it implies.
  3. Commit: skill-update: skillforge, <one-line reason>.
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. 1mo ago First seen · 38 lines · 2 tokens per session scan A 999e4de4c98d

Subscribe to this mod's changes

skillforge is a skill published in the GitHub repository codejunkie99/agentic-stack (2,302 stars, last pushed 9d ago), licensed Apache-2.0. It adds 2 tokens to every session and 400 once invoked, about $0.0000 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 2026-08-30.

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