Subagents

Specialized AI assistants for specific tasks

Subagents require Multi mode to be selected. Use Cmd/Ctrl . to toggle between modes.

Custom subagents in Firebender are specialized AI assistants that can be invoked to handle specific types of tasks. They enable more efficient problem-solving by providing task-specific configurations with customized system prompts, tools and a separate context window.

What are subagents?

Subagents are pre-configured AI personalities that Firebender can delsayegate tasks to. Each subagent:

• Has a specific purpose and expertise area
• Uses its own context window separate from the main conversation
• Can be configured with specific tools it’s allowed to use
• Includes a custom system prompt that guides its behavior

When Firebender encounters a task that matches a subagent’s expertise, it can delegate that task to the specialized subagent, which works independently and returns results.

Creating subagents

You can use the /subagents slash command to list existing subagents and create new ones:

File format

Each subagent is defined in a Markdown file with this structure:

---
name: your-sub-agent-name
description: Description of when this subagent should be invoked
tools: tool1, tool2, tool3 # Optional - inherits all tools if omitted
model: haiku # Optional - specify model alias
---

Your subagent's system prompt goes here. This can be multiple paragraphs
and should clearly define the subagent's role, capabilities, and approach
to solving problems.

Include specific instructions, best practices, and any constraints
the subagent should follow.

Configuration fields

Field	Required	Description
name	Yes	Unique identifier using lowercase letters and hyphens
description	Yes	Natural language description of the subagent’s purpose
tools	No	Comma-separated list of specific tools. If omitted, inherits all tools from the main thread
model	No	Model to use for this subagent. Can be a model alias (sonnet, opus, haiku). If omitted, defaults to the configured subagent model

Available tools

You can configure subagents with any of the following tools:

• read_file - Read files from the codebase
• list_dir - List directory contents
• grep_search - Search file contents with regex patterns
• file_search - Fuzzy search for files by path
• delete_file - Delete files
• run_terminal_cmd - Execute terminal commands
• web_search - Search the web for information
• edit_file - Edit files in the codebase

Configuration

Subagents are configured in your firebender.json file using the subagents array:

{
  "subagents": [
    ".firebender/subagents/code-reviewer.md",
    "~/firebender-subagents/test-generator.md",
    "/absolute/path/to/subagent.md"
  ]
}

Paths support:

• Relative paths: .firebender/subagents/my-subagent.md (relative to project root for project config, ~/.firebender for personal config)
• Home directory: ~/my-subagents/subagent.md
• Absolute paths: /path/to/subagent.md

When configured in project-level firebender.json, subagents are available in the current project. When configured in personal ~/.firebender/firebender.json, they’re available across all projects.

Related documentation

• Agent - Learn about Firebender’s agent modes
• Subagent Configs Cookbook - Real-world examples of subagent configurations
• Commands - Custom AI commands for your exact workflow
• MCP - Extend Firebender with Model Context Protocol