Function createReactAgent

packages/components/src/agents.ts:770–796

({ llm, tools, prompt }: CreateReactAgentParams)

}

export const createReactAgent = async ({ llm, tools, prompt }: CreateReactAgentParams) => {
    const missingVariables = ['tools', 'tool_names', 'agent_scratchpad'].filter((v) => !prompt.inputVariables.includes(v))
    if (missingVariables.length > 0) {
        throw new Error(`Provided prompt is missing required input variables: ${JSON.stringify(missingVariables)}`)
    }
    const toolNames = tools.map((tool) => tool.name)
    const partialedPrompt = await prompt.partial({
        tools: renderTextDescription(tools),
        tool_names: toolNames.join(', ')
    })
    // TODO: Add .bind to core runnable interface.
    const llmWithStop = (llm as BaseLanguageModel).withConfig({
        stop: ['\nObservation:']
    })
    const agent = RunnableSequence.from([
        RunnablePassthrough.assign({
            //@ts-ignore
            agent_scratchpad: (input: { steps: AgentStep[] }) => formatLogToString(input.steps)
        }),
        partialedPrompt,
        llmWithStop,
        new ReActSingleInputOutputParser({
            toolNames
        })
    ])
    return agent
}

class ReActSingleInputOutputParser extends AgentActionOutputParser {
    lc_namespace = ['langchain', 'agents', 'react']