Behaviour for resolving tool calls to execution functions.

Host applications implement this behaviour to map tool names to actual execution logic. The agentic loop uses the resolver to dispatch tool calls requested by the LLM.

Example

defmodule MyApp.ToolResolver do
  @behaviour LlmToolkit.ToolResolver

  @impl true
  def resolve(%LlmToolkit.Tool.Call{name: "search", arguments: args}) do
    case MyApp.Search.run(args["query"]) do
      {:ok, results} -> {:ok, format_results(results)}
      {:error, reason} -> {:error, inspect(reason)}
    end
  end

  def resolve(%LlmToolkit.Tool.Call{name: name}) do
    {:error, "Unknown tool: #{name}"}
  end

  @impl true
  def available_tools do
    [
      %LlmToolkit.Tool{
        name: "search",
        description: "Search the knowledge base",
        parameters: %{"type" => "object", "properties" => %{"query" => %{"type" => "string"}}}
      }
    ]
  end
end

Dispatch Recipes (Optional)

Implement dispatch_recipe/1 to delegate a tool to an orchestrated sub-tool pipeline instead of direct resolve/1 execution.

@impl true
def dispatch_recipe("research_domain"), do: &MyRecipes.research_domain/1
def dispatch_recipe(_), do: nil