Add a feature flag config to opt out of tool calls in ActiveRecord integration

[darthrighteous]

Currently, the acts_as_chat and acts_as_message macros always include the “ToolCall” machinery — associations, and methods calls. This requires the dependent project to create the tool_calls table even if they never invoke tools. In my Rails app, I'm not using tools at all (at least for the foreseeable future), so having to carry around an unused table and associations seems unnecessary.

I'm thinking that not using tools seems like a common enough use case, so that it makes sense to treat tool calls in the ActiveRecord integration like an add-on, and not something that must be included from the start.

My proposal is to include a config value that behaves like a feature flag to opt out of the tool call parts of the ActiveRecord integration.

  config.active_record_use_tool_calls = false # (defaults to true so backwards compatible)

No changes would be made to the core library or how tool calls are implemented, just in the ActiveRecord integration. I implemented a proof of concept PR in a fork.

Does this seem sensible?

[InsightForesight]

I think this proposal is great.
My project doesn't really need tool calls, and adding it would just complicate things.
Actually, I came across this issue because I've been trying to remove the tool's dependency.

[onurozer]

This is a great idea. This part of the docs is also currently a bit confusing:

You’ll also need a ToolCall model if you plan to use Tools.

This implies that it's possible to just generate models for Chat and Message but not ToolCall, which is exactly what I did. But this returns an error when running chat.ask method:

Missing model class ToolCall for the Message#tool_calls association. (NameError)
uninitialized constant Message::ToolCall

Treating tool calls as optional would be perfect.

[tristandunn]

Since acts_as_chat and acts_as_message already accept a tool_call_class option, would it make sense to allow setting that to nil to disable tools for specific models? That would allow some models to use tools and some not to, if that were ever desired.

act_as_message tool_call_class: nil

It might also be nice to only have to specify the tool_call_class for one of the acts_as_* calls since it's only used once for chat in relation to a message completion, which it could instead retrieve tool_call_class from message similar to how it does for the foreign_key below.

       def persist_message_completion(message)
         return unless message

         if message.tool_call_id
-          tool_call_id = self.class.tool_call_class.constantize.find_by(tool_call_id: message.tool_call_id)&.id
+          tool_call_id = @message.class.tool_call_class.constantize.find_by(tool_call_id: message.tool_call_id)&.id
         end

         # ...
         @message.write_attribute(@message.class.tool_call_foreign_key, tool_call_id) if tool_call_id
         @message.save!
         persist_tool_calls(message.tool_calls) if message.tool_calls.present?
       end

[crmne]

@onurozer You're absolutely right that the docs were misleading. I just updated them to be clear that the ToolCall model is required, not optional.

Making ToolCall truly optional would require conditional associations and configuration complexity that isn't worth it.

The ToolCall table will be empty if you don't use tools, and that's perfectly fine. It's just standard Rails scaffold.

Docs are fixed, closing this issue.