Motivation

• Prevent a client-side crash (ZeroDivisionError) in the default progress handler when an MCP server emits total=0, which could be abused by an untrusted or buggy server to abort tool execution.

Description

• Update default_progress_handler to only compute a percentage when total not in (None, 0) and add an elif total == 0 branch that logs the raw progress/total string without dividing, and add test_default_progress_handler_handles_zero_total to tests/client/test_progress.py to cover the case.

Testing

• Ran uv sync (succeeded), ran the full suite with uv run pytest -n auto (the repository-wide run reported unrelated failures/timeouts), ran uv run pytest tests/client/test_progress.py (4 passed), and attempted uv run prek run --all-files which failed to initialize hooks due to external network access to codespell (403).

Codex Task