What is create-sub-agent?

A guided tool for creating a Claude Code sub-agent, a separate assistant with its own instructions and tool permissions.

Use it to create project-level or personal sub-agents for focused development tasks.

It helps choose the right location, model, permissions, and optional integrations while following Claude Code's required file format.

create-sub-agent — Skill for Claude Code by tsmztech

Install

Getting it into your agent

This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.

Claude Code

/plugin marketplace add tsmztech/claude-code-plugins

Claude Code

/plugin install claude-craft

Made for: Claude Code.

Or install claude-craft, the plugin that ships this one along with the rest of its 4 skills, 2 commands.

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/tsmztech/claude-code-plugins/create-sub-agent/github.svg)](https://agentmods.dev/skills/tsmztech/claude-code-plugins/create-sub-agent)

Your own site

<a href="https://agentmods.dev/skills/tsmztech/claude-code-plugins/create-sub-agent"><img src="https://agentmods.dev/badge/skills/tsmztech/claude-code-plugins/create-sub-agent/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/tsmztech/claude-code-plugins/create-sub-agent"><img src="https://agentmods.dev/badge/skills/tsmztech/claude-code-plugins/create-sub-agent.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 23 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 365 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.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00023	$0.00365
Opus 5.5	$0.00009	$0.00146
Sonnet 5.5	$0.00005	$0.00073
Haiku 4.5	$0.00002	$0.00036

Measured 2mo ago against content hash cf37c7ffb530, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

create-sub-agent 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 2mo 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-craft/skills/create-sub-agent/SKILL.md · 34 lines

What it actually says

Create a Claude Code Sub-Agent

Read first: ${CLAUDE_PLUGIN_ROOT}/docs/sub-agents.md — this is the full reference for sub-agent structure, frontmatter fields, permission modes, hooks, and examples. Use it to guide every decision.

Determine target location

Check if the user passed a path as $ARGUMENTS.

Path given → create at <path>/.claude/agents/<sub-agent-name>.md
personal → create at ~/.claude/agents/<sub-agent-name>.md
Nothing → ask where. Explain project vs personal scope (see "Choose the subagent scope" in the doc)

Gather requirements

Ask the user what the sub-agent should do. From their answer, use the doc to determine:

What the system prompt should contain (see "Write subagent files")
Which tools it needs and which to deny (see "Available tools")
Which model fits — haiku for fast/cheap, sonnet for balanced, opus for complex, inherit for same as parent (see "Choose a model")
Whether it needs a specific permission mode (see "Permission modes")
Whether it needs preloaded skills, persistent memory, MCP servers, or hooks (see respective sections in the doc)

Create the sub-agent

Follow the conventions from the doc for file format and naming. Check if the target already exists before writing — never overwrite without asking.

After creating, tell the user how to test it.

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.

2mo ago First seen · 34 lines · 23 tokens per session scan A cf37c7ffb530

Subscribe to this mod's changes

create-sub-agent is a skill published in the GitHub repository tsmztech/claude-code-plugins (2 stars, last pushed 8mo ago), licensed MIT. It adds 23 tokens to every session and 365 once invoked, about $0.0001 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 2026-08-31.

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