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Tools & Agents ​

Tools ​

Tools let you define functions that the LLM can invoke during a conversation. The LLM sees the tool's name, description, and parameter schema, and can call it when appropriate.

deftool ​

Define a tool with a name, description, parameter schema, and handler function.

scheme
(deftool lookup-capital
  "Look up the capital of a country"
  {:country {:type :string :description "Country name"}}
  (lambda (country)
    (cond
      ((= country "Norway") "Oslo")
      ((= country "France") "Paris")
      (else "Unknown"))))

Using Tools with Chat ​

Pass tools to llm/chat — the LLM will call them automatically when needed.

scheme
(llm/chat
  [(message :user "What is the capital of Norway?")]
  {:tools [lookup-capital] :max-tokens 100})

Inspecting Tools ​

tool/name ​

scheme
(tool/name lookup-capital)              ; => "lookup-capital"

tool/description ​

scheme
(tool/description lookup-capital)       ; => "Look up the capital..."

tool/parameters ​

scheme
(tool/parameters lookup-capital)        ; => {:country {:type :string ...}}

tool? ​

scheme
(tool? lookup-capital)                  ; => #t

Agents ​

Agents combine a system prompt, tools, and a multi-turn loop. They handle the back-and-forth of tool calls automatically.

defagent ​

Define an agent with a system prompt, tools, model, and turn limit.

scheme
(deftool get-weather
  "Get weather for a city"
  {:city {:type :string}}
  (lambda (city)
    (format "~a: 22°C, sunny" city)))

(defagent weather-bot
  {:system "You are a weather assistant. Use the get-weather tool."
   :tools [get-weather]
   :model "claude-haiku-4-5-20251001"
   :max-turns 3})

agent/run ​

Run an agent with a user message. The agent will loop, calling tools as needed, until it has a final answer or hits the turn limit.

scheme
(agent/run weather-bot "What's the weather in Tokyo?")

Inspecting Agents ​

agent/name ​

scheme
(agent/name weather-bot)                ; => "weather-bot"

agent/system ​

scheme
(agent/system weather-bot)              ; => "You are a weather assistant..."

agent/tools ​

scheme
(agent/tools weather-bot)               ; => list of tool values

agent/model ​

scheme
(agent/model weather-bot)               ; => "claude-haiku-4-5-20251001"

agent/max-turns ​

scheme
(agent/max-turns weather-bot)           ; => 3

agent? ​

scheme
(agent? weather-bot)                    ; => #t