unexpected XML syntax from LLM causes agent to output ">\</final-answer>" after first step

[Music4Dogs]

Issue Type

Agent Issue

Operating System

Windows

Description of the bug

When asking multiple different models up to and around 24b, they will often interpret the system prompt as though the "<final-answer></final-answer>" syntax should be output exactly as shown here, with no newline. This appears to break the agent, causing it to output "></final-answer>" as a final response and stop the agent's workflow.

Steps to Reproduce

1. Load a small language model. (InternVL-3.5-14b, 8b, and magistral small 24b were tested)
2. make a simple request that should result in a multi-step agent workflow, such as navigating to two separate pages sequentially.

Screenshots / Videos

BrowserOS Version

137.0.7215.69

Additional Context

After updating to latest, none of the models i am capable of running locally will perform a multi-step workflow due to their interpretations of the system prompt not aligning with the expected response format, and presumably breaking the expected xml format. This could be solved by including more detailed clarification of the expected response structure in the system prompt, or adding the option to manually edit the agent's prompt to allow users to account for quirks with language models the BrowserOS team can't individually rewriting the system prompt for.