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.
npx agentmods add skills/marcusgoll/spec-flow/create-subagentsnpx skills add marcusgoll/Spec-Flow --skill create-subagentsgit clone --depth 1 https://github.com/marcusgoll/Spec-FlowWhat 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 | $0.00049 | $0.02284 |
| Opus 5 | $0.00024 | $0.01142 |
| Sonnet 5 | $0.00010 | $0.00457 |
| Haiku 4.5 | $0.00005 | $0.00228 |
Grade A, and why
create-subagents 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 3d 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.
This is a copy
100% identical to create-subagents — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 308 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Subagents enable delegation of complex tasks to specialized agents that operate autonomously without user interaction, returning their final output to the main conversation.
<quick_start>
- Run
/agentscommand - Select "Create New Agent"
- Choose project-level (
.claude/agents/) or user-level (~/.claude/agents/) - Define the subagent:
- name: lowercase-with-hyphens
- description: When should this subagent be used?
- tools: Optional comma-separated list (inherits all if omitted)
- model: Optional (
sonnet,opus,haiku, orinherit)
- Write the system prompt (the subagent's instructions)
<focus_areas>
- Code quality and maintainability
- Security vulnerabilities
- Performance issues
- Best practices adherence </focus_areas>
<output_format> Provide specific, actionable feedback with file:line references. </output_format>
</example>
</quick_start>
<file_structure>
| Type | Location | Scope | Priority |
|------|----------|-------|----------|
| **Project** | `.claude/agents/` | Current project only | Highest |
| **User** | `~/.claude/agents/` | All projects | Lower |
| **Plugin** | Plugin's `agents/` dir | All projects | Lowest |
Project-level subagents override user-level when names conflict.
</file_structure>
<configuration>
<field name="name">
- Lowercase letters and hyphens only
- Must be unique
</field>
<field name="description">
- Natural language description of purpose
- Include when Claude should invoke this subagent
- Used for automatic subagent selection
</field>
<field name="tools">
- Comma-separated list: `Read, Write, Edit, Bash, Grep`
- If omitted: inherits all tools from main thread
- Use `/agents` interface to see all available tools
</field>
<field name="model">
- `sonnet`, `opus`, `haiku`, or `inherit`
- `inherit`: uses same model as main conversation
- If omitted: defaults to configured subagent model (usually sonnet)
</field>
</configuration>
<execution_model>
<critical_constraint>
**Subagents are black boxes that cannot interact with users.**
Subagents run in isolated contexts and return their final output to the main conversation. They:
- ✅ Can use tools like Read, Write, Edit, Bash, Grep, Glob
- ✅ Can access MCP servers and other non-interactive tools
- ❌ **Cannot use AskUserQuestion** or any tool requiring user interaction
- ❌ **Cannot present options or wait for user input**
- ❌ **User never sees subagent's intermediate steps**
The main conversation sees only the subagent's final report/output.
</critical_constraint>
<workflow_design>
**Designing workflows with subagents:**
Use **main chat** for:
- Gathering requirements from user (AskUserQuestion)
- Presenting options or decisions to user
- Any task requiring user confirmation/input
- Work where user needs visibility into progress
Use **subagents** for:
- Research tasks (API documentation lookup, code analysis)
- Code generation based on pre-defined requirements
- Analysis and reporting (security review, test coverage)
- Context-heavy operations that don't need user interaction
**Example workflow pattern:**
Main Chat: Ask user for requirements (AskUserQuestion) ↓ Subagent: Research API and create documentation (no user interaction) ↓ Main Chat: Review research with user, confirm approach ↓ Subagent: Generate code based on confirmed plan ↓ Main Chat: Present results, handle testing/deployment
</workflow_design>
</execution_model>
What ships with it
7 files 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.
- 3d ago First seen · 308 lines · 49 tokens per session scan A 2f11e2dc66e7
create-subagents is a skill published in the GitHub repository marcusgoll/Spec-Flow (91 stars, last pushed 4mo ago), licensed MIT. It adds 49 tokens to every session and 2,284 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to create-subagents, differing in 0 lines, and is treated as a copy.
Other skills, from other repositories
writing-for-agents
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tdd
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grilling
Grill the user relentlessly about a plan, decision, or idea. Use when the user wants to stress-test their thinking, or uses any 'grill' trigger phrases.
advogado-criminal
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agent-evaluation-reporting
Use when summarizing agent evaluations where autonomous, assisted, failed, timed-out, or invalid outcomes must remain distinct and comparable.
agent-orchestration-multi-agent-optimize
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