Feature Request: Make `markdown_live` `vertical_overflow` Configurable

[wangengzheng]

Problem

Currently, markdown_live rendering uses Rich's Live display with vertical_overflow="ellipsis" behavior.

While this works well for most cases, it creates a poor experience during long-running REPL interactions or agent workflows.

When the output exceeds the terminal height, users only see:

...

for extended periods of time.

This causes two issues:

1. Lack of visibility

   • Users cannot tell what the model is currently doing.

   • Long-running operations appear stalled even when progress is being made.

2. Reduced educational value

   • One of the benefits of AI-assisted workflows is observing the reasoning process, generated commands, tool calls, and intermediate outputs.

   • With ellipsis, much of this information is hidden from view.

Proposed Solution

Expose vertical_overflow as a configurable option for markdown live rendering.

Example:

Live(

    renderable,

    vertical_overflow=config.vertical_overflow,

)

Possible values:

ellipsis

visible

crop

Default behavior should remain unchanged:

vertical_overflow = "ellipsis"

so existing users are not affected.

Benefits

• Preserves backward compatibility.

• Improves visibility during long-running REPL sessions.

• Makes debugging easier.

• Allows users to observe AI-generated intermediate output in real time.

• Better learning experience for users interested in understanding how the model is solving a problem.

Additional Changes

I also plan to:

• Update README.md

• Document the new configuration option

• Provide examples of the different vertical_overflow modes and their effects

Example Use Case

For interactive REPL sessions:

vertical_overflow = "visible"

Users can continuously observe generated markdown output, tool execution details, and progress updates instead of staring at:

...

for several minutes.

[wangengzheng]

https://github.com/Textualize/rich/blob/master/rich/live.py

https://rich.readthedocs.io/en/latest/live.html

 vertical_overflow: VerticalOverflowMethod = "ellipsis",