Hacktoberfest 2026: as issues que os mantenedores marcaram para outubro, abertas e boas para iniciantes. Ver issues do Hacktoberfest

Bug in the official tutorial docs: Tool use example code lacks agentic loop, causing multi-turn calls to fail

Aberta
  • Algo errado?
#233 1 comentário 2 reações 0 responsáveis Ver no GitHub

Mantenedores costumam responder em até 6 dias

Ninguém assumiu esta issue ainda.

Avaliação

Dificuldade
3/5
Tempo estimado
1-2 dias
Facilidade para iniciantes
76/100
Tipo de issue
Bug
Clareza
Claramente especificada
Status de atividade
Ativa
Stack de tecnologia
python
Domínio
documentation

Direção de pesquisa

Start with “The Query Processing Logic” in the MCP building tutorial at the linked build-client page, focusing on the async process_query function and its message handling. Confirm that repeated tool_use responses are processed with their tool results until a plain-text response is returned, including tool execution errors; the issue’s corrected snippet defines the expected behavior.

Escrita pelo modelo de indexação a partir do texto da issue.

Descrição

The original example code (The Query Processing Logic in the MCP building tutorial site https://modelcontextprotocol.io/docs/2026-07-28/develop/build-client) has the following core issues:

  • Single-turn Limitation: After the initial API call, the code only checks and processes tool_use blocks once. If Claude requests additional tool calls in its second response (e.g., needing to chain a second tool based on the output of the first), the original code fails to handle them—it simply ignores subsequent tool calls, causing complex multi-step tasks to fail.
  • Lack of Agentic Loop Structure: It does not use a loop to continuously maintain conversation state. A correct implementation should, after each model response, check whether tool_use blocks are present; if so, execute the tools, append the results to the message history, and continue with the next API call—repeating this cycle until the model outputs a plain-text final answer.

The following corrected snippet resolves these issues by introducing a while True loop, correctly implementing a multi-turn tool-calling agent loop. Below is the corrected code version:

async def process_query(client, query: str) -> str:
    
    messages = [
        {"role": "user",
         "content": query}
    ]

    tool_list = await client.list_tools()
    available_tools = [{
        "name": tool.name,
        "description": tool.description,
        "input_schema": tool.input_schema,
    } for tool in tool_list.tools]

    final_texts = []

    while True:
        response = await anthropic.messages.create(
            model=MODEL,
            max_tokens=1000,
            messages=messages,
            tools=available_tools,
        )

        # Append the full assistant response back to the message history for context
        messages.append({
            "role": "assistant",
            "content": response.content,
        })

        tool_uses = []

        for block in response.content:
            if block.type == "text":
                final_texts.append(block.text)
            elif block.type == "tool_use":
                tool_uses.append(block)

        # If no tool_use is requested, this is the final answer; exit the loop
        if not tool_uses:
            break

        tool_results = []

        for block in tool_uses:
            try:
                result = await client.call_tool(block.name, block.input)

                tool_results.append({
                    "type": "tool_result",
                    "tool_use_id": block.id,
                    "content": format_tool_result(result),  # Assumes format_tool_result is defined elsewhere
                    "is_error": bool(result.is_error),
                })
            except Exception as e:
                # Tool execution errors must also be returned as tool_result to the model
                tool_results.append({
                    "type": "tool_result",
                    "tool_use_id": block.id,
                    "content": f"Tool execution error: {e}",
                    "is_error": True,
                })

        # Feed the tool results back as a user message to continue the next turn
        messages.append({
            "role": "user",
            "content": tool_results,
        })

    return "\n".join(final_texts)

(Note: format_tool_result is assumed to be a helper function that extracts text from the tool response, similar to "\n".join(block.text for block in result.content if isinstance(block, TextContent)) in the original code.)

Linguagem predominante
TypeScript
Estrelas
1.2k
Forks
693
Merge médio
4d 1h
PRs com merge (30d)
27

Preparar o ambiente

Primeiros passos

  1. Leia a issue inteira e depois o guia de contribuição do projeto.
  2. Comente na issue dizendo que vai assumir — evita que duas pessoas façam o mesmo trabalho.
  3. Faça um fork do repositório e trabalhe em uma branch.
  4. Abra um pull request que referencie o número da issue.

Mais de modelcontextprotocol/quickstart-resources

Todas as issues de modelcontextprotocol/quickstart-resources

Issues semelhantes

Mais issues de TypeScript

Receba novas issues na sua caixa de entrada

Um resumo curto de issues do GitHub para quem está começando.