Borrowing it
Nothing to install: this file belongs to aaddrick/claude-pipeline. 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/aaddrick/claude-pipeline/main/.claude/skills/writing-agents/SKILL.mdgit clone --depth 1 https://github.com/aaddrick/claude-pipelineWrote 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/skills/aaddrick/claude-pipeline/writing-agents)<a href="https://agentmods.dev/skills/aaddrick/claude-pipeline/writing-agents"><img src="https://agentmods.dev/badge/skills/aaddrick/claude-pipeline/writing-agents/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/skills/aaddrick/claude-pipeline/writing-agents"><img src="https://agentmods.dev/badge/skills/aaddrick/claude-pipeline/writing-agents.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 | $0.00024 | $0.03008 |
| Opus 5 | $0.00012 | $0.01504 |
| Sonnet 5 | $0.00005 | $0.00602 |
| Haiku 4.5 | $0.00002 | $0.00301 |
Grade A, and why
writing-agents 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 10d 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.
How it starts
The opening of the file, as written. The whole thing — 452 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Writing Agents
Overview
Writing agents IS Test-Driven Development applied to role definitions.
Agents are specialized subagents invoked via the Task tool. They receive full conversation context and execute autonomously with a defined persona, tools, and behavioral guidelines.
Core principle: If you didn't test the agent on representative tasks, you don't know if it performs correctly.
REQUIRED BACKGROUND: Understand test-driven-development and writing-skills before using this skill. Same RED-GREEN-REFACTOR cycle applies.
Agents vs Skills
| Aspect | Agents | Skills |
|---|---|---|
| Invocation | Task tool with subagent_type |
Skill tool with skill name |
| Context | Full conversation history | Loaded on-demand |
| Execution | Autonomous, multi-turn | Single response guidance |
| Persona | Explicit role/identity | Reference documentation |
| Location | .claude/agents/ |
.claude/skills/ |
| Use for | Complex, autonomous tasks | Reusable patterns/techniques |
Agent File Structure
Agents are PROJECT-LEVEL. They live in the project's .claude/agents/ directory, not personal directories.
.claude/agents/
agent-name.md # Single file with frontmatter + persona
Frontmatter (YAML):
---
name: agent-name
description: Role description. Use for [specific task types].
model: opus # Optional: opus, sonnet, haiku (defaults to parent)
---
IMPORTANT: After creating or modifying an agent, prompt the user to restart their Claude Code session. Agents are loaded at session start and won't be available until restart.
Agent Creation Workflow
Before writing the agent, gather domain knowledge and project context:
Step 1: Research Domain Best Practices
Use WebSearch to find domain-specific guidance. Search for:
- Best practices for [domain] development
- Common [domain] mistakes/anti-patterns
- [Domain] code review checklist
- [Technology] security considerations
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.
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.
- 10d ago First seen · 452 lines · 24 tokens per session scan A 461962c6d8fa
writing-agents is a skill published in the GitHub repository aaddrick/claude-pipeline (128 stars, last pushed 6mo ago), licensed MIT. It adds 24 tokens to every session and 3,008 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.
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