[Multi Actions] Fix bug where assistant tries to use tool even if not allowed

[fontanierh]

Mostly observed on 3.5 sonnet. Could be related to system prompt We could decide to:

• change system prompt to discourage this (or at least not encourage it when no tools are allowed)
• increase max steps to limit cases where we would have this error
• check if the "dummy tool" hack is still required, if not remove and see if we still have the issue

[fontanierh]

It is somewhat similar to https://github.com/dust-tt/tasks/issues/940

[fontanierh]

Anyway, this starts with a good repro.

We have the run here: https://dust.tt/w/78bda07b39/a/0e9889c787/runs/18eee44fd1511f2c767f031dac494afb588217cffb0a23c0e1c77db32518a24d

Now we need to reproduce it

[spolu]

As per IRL, first step is really to ensure we have a digestible error for users that invites them to retry. Is that the case right now?

From there we can optimize with Anthropic to prevent this as much as possible.

[fontanierh]

@spolu we have the one you added here: https://github.com/dust-tt/dust/blob/3e2281e2eb3b6e048a109a318d4c04ded4612f57/front/lib/api/assistant/agent.ts#L649

[spolu]

Maybe we should add a sentence to invite to retry in that case?