The LLMAgent is used in an AgentExecutor. This AgentExecutor can largely be thought of as a loop that:
1. Passes user input and any previous steps to the Agent (in this case, the LLMAgent)
2. If the Agent returns an `AgentFinish`, then return that directly to the user
3. If the Agent returns an `AgentAction`, then use that to call a tool and get an `Observation`
4. Repeat, passing the `AgentAction` and `Observation` back to the Agent until an `AgentFinish` is emitted.

`AgentAction` is a response that consists of `action` and `action_input`. `action` refers to which tool to use, and `action_input` refers to the input to that tool. `log` can also be provided as more context (that can be used for logging, tracing, etc).

`AgentFinish` is a response that contains the final message to be sent back to the user. This should be used to end an agent run.

import CodeBlock from "@theme/CodeBlock";
import Example from "@examples/agents/custom_llm_agent_chat.ts";

<CodeBlock language="typescript">{Example}</CodeBlock>