Tools

Brute ships with 11 built-in tools that give the agent access to the filesystem, network, and task management.

Built-in Tools

Tool	Class	Purpose
`read`	`FSRead`	Read files (supports line ranges)
`write`	`FSWrite`	Create/overwrite files
`patch`	`FSPatch`	Find-and-replace in files
`remove`	`FSRemove`	Delete files/directories
`fs_search`	`FSSearch`	Ripgrep content search with glob filter
`undo`	`FSUndo`	Revert last file mutation
`shell`	`Shell`	Execute commands (5 min timeout, 50KB cap)
`fetch`	`NetFetch`	HTTP GET
`todo_write`	`TodoWrite`	Replace task list
`todo_read`	`TodoRead`	Read task list
`question`	`Question`	Ask user interactive questions

Using Tools

Pass tools when creating an agent. Use Brute::Tools::ALL for the full set:

agent = Brute::Agent.new(
  provider: Brute.provider,
  model:    "claude-sonnet-4-20250514",
  tools:    Brute::Tools::ALL,
) do
  use Brute::Middleware::SystemPrompt
  use Brute::Middleware::ToolResultLoop
  use Brute::Middleware::MaxIterations
  use Brute::Middleware::ToolCall
  run Brute::Middleware::LLMCall.new
end

For a restricted, read-only agent:

agent = Brute::Agent.new(
  provider: Brute.provider,
  model:    "claude-sonnet-4-20250514",
  tools:    [Brute::Tools::FSRead, Brute::Tools::FSSearch],
) do
  use Brute::Middleware::SystemPrompt
  use Brute::Middleware::ToolResultLoop
  use Brute::Middleware::MaxIterations
  use Brute::Middleware::ToolCall
  run Brute::Middleware::LLMCall.new
end

Sub-Agent Delegation

For delegating tasks to other agents, use Brute::SubAgent rather than a built-in tool. Sub-agents are wrapped as tools via .to_ruby_llm and registered in the parent agent's tool list:

explorer = Brute::SubAgent.new(
  name:        "explore_code",
  description: "Delegate a code exploration task to a read-only sub-agent.",
  provider:    Brute.provider,
  model:       "claude-sonnet-4-20250514",
  tools:       [Brute::Tools::FSRead, Brute::Tools::FSSearch],
) do
  use Brute::Middleware::SystemPrompt
  use Brute::Middleware::Summarize
  use Brute::Middleware::ToolResultLoop
  use Brute::Middleware::MaxIterations, max_iterations: 15
  use Brute::Middleware::ToolCall
  run Brute::Middleware::LLMCall.new
end

# Register the sub-agent as a tool in the parent agent
agent = Brute::Agent.new(
  provider: Brute.provider,
  model:    "claude-sonnet-4-20250514",
  tools:    [explorer.to_ruby_llm],
) do
  # ...
end

See examples/07_subagent_exploration.rb for a full working example with parallel sub-agents.