Custom subagents

Custom agents

Custom agents are Markdown files with YAML frontmatter and a system prompt body. Make the body self-contained and lead with the outcome:

State the role or goal and observable success criteria.
Define constraints, context-dependent tool routes, and the required output shape.
Say when the agent should stop.

Reserve absolute wording for true invariants. Request evidence and conclusions rather than private reasoning, and avoid repeated self-check instructions. Common locations are:

Scope	Path
User	`~/.atomic/agent/agents/*/.md`
Project	`.atomic/agents/*/.md`

A small custom read-only inspection agent:

---
name: strict-inspector
description: Inspect code for correctness and regressions
tools: read, search, bash
model: anthropic/claude-sonnet-4
fallbackModels: openai/gpt-5-mini
inheritProjectContext: true
---

## Role and goal
Inspect the current diff for correctness and regressions without editing files.

## Success criteria
Cite each actionable issue with file:line evidence and the observed failure or risk.

## Output and stop rule
Return only issues worth fixing now. Stop when the relevant diff and affected call paths have been inspected, or name the evidence you could not access.

To choose an execution model separately for each task, set model: auto instead of a concrete model. Atomic uses the current available catalog and its shipped evaluation guidance before launching the child. A concrete per-call override bypasses this automatic choice. Optional modelConstraints restricts eligible choices and fallbacks; see Automatic model selection for the settings, supported fields, and failure behavior.

Build with Atomic

Extend a session

Orchestrate work

Distribute

Models and providers

Programmatic use

Custom subagents

Custom subagents

Custom agents

​Custom subagents

​Custom agents

Custom subagents

Custom agents