An assistant message with 'tool_calls' must be followed by tool messages responding to each 'tool_call_id' #285

guizaols · 2025-07-17T19:52:02Z

guizaols
Jul 17, 2025

I'm building a WhatsApp agent with RubyLLM. After a few questions asked and answered the flow just stops because of the error:

DEBUG -- RubyLLM: error: /Users/guizaols/.local/share/mise/installs/ruby/3.3.5/lib/ruby/gems/3.3.0/gems/ruby_llm-1.3.1/lib/ruby_llm/error.rb:61:in `parse_error': An assistant message with 'tool_calls' must be followed by tool messages responding to each 'tool_call_id'. The following tool_call_ids did not have response messages: call_X2wM00xBDQhFbs681BZAZUEt (RubyLLM::BadRequestError)
	from /Users/guizaols/.local/share/mise/installs/ruby/3.3.5/lib/ruby/gems/3.3.0/gems/ruby_llm-1.3.1/lib/ruby_llm/error.rb:49:in `block in call'
	from /Users/guizaols/.local/share/mise/installs/ruby/3.3.5/lib/ruby/gems/3.3.0/gems/faraday-2.13.2/lib/faraday/response.rb:42:in `on_complete'
	from /Users/guizaols/.local/share/mise/installs/ruby/3.3.5/lib/ruby/gems/3.3.0/gems/ruby_llm-1.3.1/lib/ruby_llm/error.rb:48:in `call'
	from /Users/guizaols/.local/share/mise/installs/ruby/3.3.5/lib/ruby/gems/3.3.0/gems/faraday-2.13.2/lib/faraday/middleware.rb:56:in `call'
	from /Users/guizaols/.local/share/mise/installs/ruby/3.3.5/lib/ruby/gems/3.3.0/gems/faraday-2.13.2/lib/faraday/middleware.rb:56:in `call'
	from /Users/guizaols/.local/share/mise/installs/ruby/3.3.5/lib/ruby/gems/3.3.0/gems/faraday-retry-2.3.2/lib/faraday/retry/middleware.rb:171:in `block in call'
	from /Users/guizaols/.local/share/mise/installs/ruby/3.3.5/lib/ruby/gems/3.3.0/gems/faraday-retry-2.3.2/lib/faraday/retry/retryable.rb:7:in `with_retries'
	from /Users/guizaols/.local/share/mise/installs/ruby/3.3.5/lib/ruby/gems/3.3.0/gems/faraday-retry-2.3.2/lib/faraday/retry/middleware.rb:167:in `call'
	from /Users/guizaols/.local/share/mise/installs/ruby/3.3.5/lib/ruby/gems/3.3.0/gems/faraday-2.13.2/lib/faraday/middleware.rb:56:in `call'
	from /Users/guizaols/.local/share/mise/installs/ruby/3.3.5/lib/ruby/gems/3.3.0/gems/faraday-2.13.2/lib/faraday/response/logger.rb:25:in `call'
	from /Users/guizaols/.local/share/mise/installs/ruby/3.3.5/lib/ruby/gems/3.3.0/gems/faraday-2.13.2/lib/faraday/rack_builder.rb:153:in `build_response'
	from /Users/guizaols/.local/share/mise/installs/ruby/3.3.5/lib/ruby/gems/3.3.0/gems/faraday-2.13.2/lib/faraday/connection.rb:452:in `run_request'
	from /Users/guizaols/.local/share/mise/installs/ruby/3.3.5/lib/ruby/gems/3.3.0/gems/faraday-2.13.2/lib/faraday/connection.rb:280:in `post'
	from /Users/guizaols/.local/share/mise/installs/ruby/3.3.5/lib/ruby/gems/3.3.0/gems/ruby_llm-1.3.1/lib/ruby_llm/connection.rb:38:in `post'
	from /Users/guizaols/.local/share/mise/installs/ruby/3.3.5/lib/ruby/gems/3.3.0/gems/ruby_llm-1.3.1/lib/ruby_llm/provider.rb:77:in `sync_response'
	from /Users/guizaols/.local/share/mise/installs/ruby/3.3.5/lib/ruby/gems/3.3.0/gems/ruby_llm-1.3.1/lib/ruby_llm/provider.rb:25:in `complete'
	from /Users/guizaols/.local/share/mise/installs/ruby/3.3.5/lib/ruby/gems/3.3.0/gems/ruby_llm-1.3.1/lib/ruby_llm/chat.rb:97:in `complete'
	from /Users/guizaols/.local/share/mise/installs/ruby/3.3.5/lib/ruby/gems/3.3.0/gems/ruby_llm-1.3.1/lib/ruby_llm/active_record/acts_as.rb:157:in `complete'
	from /Users/guizaols/.local/share/mise/installs/ruby/3.3.5/lib/ruby/gems/3.3.0/gems/ruby_llm-1.3.1/lib/ruby_llm/active_record/acts_as.rb:151:in `ask'

I get a set of data after a few shots (sometimes it happens in the second attempt). I don't know why this is hapenning

Get data

Chat.last.messages.order(:created_at).pluck(:id, :role, :content, :tool_call_id).map { |data| [data[0], data[1], data[2]&.truncate(100), data[3]] }

Data

[
  ["eec84563-3d1f-4beb-b0a5-a70445d45991", "system", "Você é um assistente...", nil],
  ["39266348-fc40-489c-84df-79260b2a1a31", "user", "quero comprar uma mesa de centro moderna", nil],
  ["382dbe17-dd4b-47b7-b691-06b52cc07b77", "assistant", nil, nil],
  ["527447b5-e6c2-4219-9039-013152908e91", "tool", "Selecionamos as melhores opções para você!", "2aada229-3b28-474e-aff1-ecd91397941c"],
  ["1bd81303-e539-42c1-a902-b228fdcd9f7a", "assistant", "Vou te ajudar a encontrar isso! 😊", nil],
  
  ["2fd36c61-a4ba-43c4-845f-27f5c6063ea5", "system", "Você é um assistente...", nil],
  ["e6f6f9a8-3f5d-4855-af60-256353ca9e4c", "user", "quero comprar uma TIPOIA INFANTIL ESTOFADA CHANTAL", nil],
  ["dd81db67-1ffc-4d03-97db-737a36df7908", "assistant", nil, nil],
  ["e453aa61-c5d4-4689-a6c1-072195327bb6", "tool", "Selecionamos as melhores opções para você!", "30068054-f76d-47e8-9314-f606d2f19a99"],
  ["780d3420-bf61-46b8-b07e-c4f29ccef308", "assistant", "Vou te ajudar a encontrar isso! 😊", nil],
  
  ["4e3c07d5-9e0c-4009-9a86-a7f79414759b", "system", "Você é um assistente...", nil],
  ["522762dd-1178-43af-9517-970d8ddb1322", "user", "quero comprar uma Caixa de som JBL Wind 3", nil],
  ["fed87204-aa93-4e28-8b83-372ab32b2c01", "assistant", nil, nil],
  ["4c4298c2-fe2f-4ba0-aa50-6267cd8eb636", "tool", "Selecionamos as melhores opções para você!", "11b7152d-4f5f-475d-8fc5-080df0fe76c8"],
  ["c9a56bbe-490c-48eb-bb7e-8803a546c790", "assistant", "Vou te ajudar a encontrar isso! 😊", nil],
  
  ["4a59873d-df4f-41a6-b898-1b8f2f5679de", "system", "Você é um assistente...", nil],
  ["fc6022ee-da8e-462c-8be9-920686d219b9", "user", "quero comprar uma chuteira nike total 90 44", nil],
  ["7e821423-4ad8-4c6e-b8d3-8f1642e0ecf7", "assistant", nil, nil],
  ["5d407937-7827-4892-b9bf-b176d055247e", "tool", "", "8df4b7c4-449d-4c25-9777-37ea1296187f"],
  ["14f17a67-f118-4e0e-a3a9-509df4e79b06", "assistant", "Vamos lá! 😊", nil],

  # ERROR!
  ["7061efff-bb54-4630-bc20-aa46e8b37f09", "system", "Você é um assistente...", nil],
  ["1ffe625d-549e-47b8-985b-ccf9da347ff4", "user", "pode ser uma camisa do corinthians", nil]
]

I already try to add manually the tool and assistant message role but with no success.
Does anyone have an ideia about this?

Answered by crmne

Aug 12, 2025

This is fixed in the latest trunk.

View full answer

tpaulshippy · 2025-07-23T04:31:43Z

tpaulshippy
Jul 23, 2025

Do you have a minimal reproducible example?

1 reply

guizaols Jul 24, 2025
Author

@tpaulshippy I'll try to figure out some way to show you that but at the momento the thing is placed in whole system and there's no easy way to reproduce out of it.

matthewlein · 2025-07-24T18:31:27Z

matthewlein
Jul 24, 2025

I also have seen these popping up from time to time and it blocks the whole chat from continuing. I'd like to understand why this is considered a blocking error.

In my case, it may happen more often when there is a timeout on a long response, but I haven't nailed it down yet.

5 replies

crmne Jul 24, 2025
Maintainer

It most likely is related to the fact that an error removes the last message, supposedly the one that caused the error, from the chat history. I guess if you get an error after we return a tool response to the assistant, subsequent messages would fail with that error. I'll improve the deletion logic!

guizaols Jul 24, 2025
Author

@matthewlein @crmne I'm guessing somethin like that as well (long time or error) but I can't really undestand fully the behavior

guizaols Jul 31, 2025
Author

@crmne I saw a new version of the gem. Any updates on this matter?

crmne Jul 31, 2025
Maintainer

@crmne I saw a new version of the gem. Any updates on this matter?

No updates but happy to see a PR fixing this!

guizaols Jul 31, 2025
Author

I'll try to digging in a few days!

ynonp · 2025-08-07T11:14:20Z

ynonp
Aug 7, 2025

Hi I have the same problem. It doesn't happen locally (in dev) but I do get these errors on staging, where the DB is slower. I can verify the tool was called and at least in my case I can trace back the error message to a message that is in the chat:

Message 102 requested tool call
Tool call had id 9
Message 103 has tool_call_id == 9

(responderai-rails):41:in `

': An assistant message with 'tool_calls' must be followed by tool messages responding to each 'tool_call_id'. The following tool_call_ids did not have response messages: call_EbOVE6YZUSiRVM9v3rARxwXr (RubyLLM::BadRequestError)

[#<ToolCall:0x00007fed0c15e888
id: 9,
message_id: 102,
tool_call_id: "call_EbOVE6YZUSiRVM9v3rARxwXr",
name: "tools--email_plan_finish_business_context",
arguments: {}
created_at: "2025-08-07 13:56:29.344760000 +0300",
updated_at: "2025-08-07 13:56:29.344760000 +0300">]

responderai-rails(prod)> Chat.find(18).messages.find(102)
=>
#<Message:0x00007fed0759d980
id: 102,
chat_id: 18,
role: "assistant",
content: nil,
model_id: "gpt-4.1-mini-2025-04-14",
input_tokens: "[FILTERED]",
output_tokens: "[FILTERED]",
tool_call_id: nil,
created_at: "2025-08-07 13:56:26.426566000 +0300",
updated_at: "2025-08-07 13:56:29.187028000 +0300",
visibility: "regular",
metadata: {},
state: "business_context">

responderai-rails(prod)> Chat.find(18).messages.find(103)
=>
#<Message:0x00007fed07594d80
id: 103,
chat_id: 18,
role: "tool",
content: "המשתמש רוצה להקים סדרת onboarding שתשלח לנרשמים חד...",
model_id: nil,
input_tokens: nil,
output_tokens: nil,
tool_call_id: 9,
created_at: "2025-08-07 13:56:30.049541000 +0300",
updated_at: "2025-08-07 13:56:32.549090000 +0300",
visibility: "regular",
metadata: {},
state: "business_context">
Any help is also appreciated

2 replies

ynonp Aug 7, 2025

Answering my own question - for me the issue was defining my own has_many :messages in the Chat model:

class Chat < ApplicationRecord
  acts_as_chat
  has_many :messages, dependent: :destroy

This overrides the base definition which adds order to the relation (from ruby_llm active record integration):

# file: ruby_llm/active_record/acts_as.rb
    module ActsAs
      extend ActiveSupport::Concern

      class_methods do # rubocop:disable Metrics/BlockLength
        def acts_as_chat(message_class: 'Message', tool_call_class: 'ToolCall')
          include ChatMethods

          @message_class = message_class.to_s
          @tool_call_class = tool_call_class.to_s

          has_many :messages,
                   -> { order(created_at: :asc) },
                   class_name: @message_class,
                   inverse_of: :chat,
                   dependent: :destroy

As my definition didn't include the order block, my messages were sent out of order and that led to this tool error from ChatGPT

tpaulshippy Aug 7, 2025

I see the same thing in ours. That 100% could be it. Thank you!

tpaulshippy · 2025-08-07T12:36:01Z

tpaulshippy
Aug 7, 2025

The one I'm getting is this:

RubyLLM::BadRequestError: messages.130: tool_use ids were found without tool_result blocks immediately after: toolu_bdrk_01XPwZcgyY7i11BaG8zFAS9i. Each tool_use block must have a corresponding tool_result block in the next message.

Different error because I'm on anthropic. But probably caused by the same race condition. It started after I switched to the rails integration for my chat interface a few days ago and has affected 5 users so far. On my list to look into.

1 reply

tpaulshippy Aug 7, 2025

https://github.com/crmne/ruby_llm/blob/main/lib/ruby_llm/active_record/acts_as.rb#L198

I think this is the suspect line @crmne was referring to. I'm also noticing an N+1 situation in the rails integration with how it loads tool calls.

crmne · 2025-08-12T17:03:28Z

crmne
Aug 12, 2025
Maintainer

This is fixed in the latest trunk.

0 replies

Uh oh!

An assistant message with 'tool_calls' must be followed by tool messages responding to each 'tool_call_id' #285

Uh oh!

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Get data

Data

Replies: 5 comments · 9 replies

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guizaols Jul 24, 2025 Author

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crmne Jul 24, 2025 Maintainer

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guizaols Jul 24, 2025 Author

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guizaols Jul 31, 2025 Author

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crmne Jul 31, 2025 Maintainer

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guizaols Jul 31, 2025 Author

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Uh oh!

crmne Aug 12, 2025 Maintainer

Replies: 5 comments 9 replies

guizaols Jul 24, 2025
Author

crmne Jul 24, 2025
Maintainer

guizaols Jul 24, 2025
Author

guizaols Jul 31, 2025
Author

crmne Jul 31, 2025
Maintainer

guizaols Jul 31, 2025
Author

crmne
Aug 12, 2025
Maintainer