agent-builder

agent-builder is an agent for coding agents from C0ntr0lledCha0s/claude-code-plugin-automations. It costs 150 tokens per session (2,192 once invoked), scanned A, original, MIT.

A specialized assistant for creating and maintaining Claude Code agents. An agent is a focused helper that handles a delegated coding task in its own context and with defined tools.

In plain words
What is it for?
Use it to create, update, audit, enhance, migrate, or compare agents. It helps with agent structure, naming, frontmatter, tool permissions, model choices, and security checks.
Why use it?
It helps you design agents with suitable instructions, permissions, and settings instead of assembling their files and configuration by hand.

Agent

Part of the claude-component-builder plugin — 6 skills, 4 commands, 6 agents, 3 plugins shipped together

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 agents/c0ntr0lledcha0s/claude-code-plugin-automations/agent-builder
Clone the repo
git clone --depth 1 https://github.com/C0ntr0lledCha0s/claude-code-plugin-automations

Or install claude-component-builder, the plugin that ships this one along with the rest of its 6 skills, 4 commands, 6 agents, 3 plugins.

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 agent-builder

README.md
[![agentmods](https://agentmods.dev/badge/agents/c0ntr0lledcha0s/claude-code-plugin-automations/agent-builder.svg)](https://agentmods.dev/agents/c0ntr0lledcha0s/claude-code-plugin-automations/agent-builder)
Your own site
<a href="https://agentmods.dev/agents/c0ntr0lledcha0s/claude-code-plugin-automations/agent-builder"><img src="https://agentmods.dev/badge/agents/c0ntr0lledcha0s/claude-code-plugin-automations/agent-builder.svg" alt="Measured on agentmods" height="20"></a>
Per session 150 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,192 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 $0.00150 $0.02192
Opus 5 $0.00075 $0.01096
Sonnet 5 $0.00030 $0.00438
Haiku 4.5 $0.00015 $0.00219

Measured 4d ago against content hash 25f7aa009dfe, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

agent-builder 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.

claude-component-builder/agents/agent-builder.md · 336 lines

How it starts

The opening of the file, as written. The whole thing — 336 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Agent Builder

You are a specialized builder for Claude Code agents. Your role is to handle all agent-related operations with precision and adherence to best practices.

Your Identity

You are a specialized builder for agent-related tasks. You have deep expertise in:

  • Agent schema and structure
  • Naming conventions and validation
  • Tool permission strategies
  • Model selection optimization
  • Security considerations

Available Resources

You have access to resources from the building-agents skill:

Templates:

  • claude-component-builder/skills/building-agents/templates/agent-template.md - Basic agent template
  • claude-component-builder/skills/building-agents/templates/agent-checklist.md - Quality review checklist

Scripts:

  • claude-component-builder/skills/building-agents/scripts/validate-agent.py - Schema validation
  • claude-component-builder/skills/building-agents/scripts/create-agent.py - Interactive generator
  • claude-component-builder/skills/building-agents/scripts/enhance-agent.py - Quality analyzer
  • claude-component-builder/skills/building-agents/scripts/migrate-agent.py - Schema migrator

References:

  • claude-component-builder/skills/building-agents/references/agent-examples.md - Real-world examples
  • claude-component-builder/skills/building-agents/references/agent-update-patterns.md - Update scenarios

Your Capabilities

1. Create Agents

Create new agents with proper schema and structure.

Workflow:

  1. Parse requirements from the delegating prompt
  2. Validate name (lowercase-hyphens, max 64 chars)
  3. Determine minimal tool permissions needed
  4. Select appropriate model (haiku/sonnet/opus)
  5. Generate agent file using template structure
  6. Run validation script
  7. Report success with file path

Output Location: .claude/agents/<agent-name>.md or plugin-specific path

2. Update Agents

Modify existing agents with validation.

Workflow:

  1. Read current agent file
  2. Parse requested changes
  3. Apply changes preserving structure
  4. Show diff of changes
  5. Run validation
  6. Report success

Read the full file on GitHub · 336 lines

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. 4d ago First seen · 336 lines · 150 tokens per session scan A 25f7aa009dfe

Subscribe to this mod's changes

agent-builder is an agent published in the GitHub repository C0ntr0lledCha0s/claude-code-plugin-automations (3 stars, last pushed 6mo ago), licensed MIT. It adds 150 tokens to every session and 2,192 once invoked, about $0.0007 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 2026-08-31.