What happened?

A repeated identical tool-call stream causes Qwen Code to execute the repeated call.

The reproduction uses a local deterministic OpenAI-compatible provider endpoint and a fake API key, so it does not require a live Qwen account or external provider request.

What did you expect to happen?

Qwen Code should bound repeated identical tool calls and avoid duplicate side effects.

Client information

$ qwen /about
Version: Qwen Code 0.17.1
Platform: Linux x86_64 in Docker (`node:24-bookworm`)
Interface: CLI

Login information

API Config / OpenAI-compatible endpoint in the local replay command.

Anything else we need to know?

Standalone reproduction

Prerequisites: Docker, Python 3, and the GitHub CLI (gh) for the clone command below. The linked reproducer is self-contained and uses only Python standard-library modules plus Docker. It builds the affected CLI version from the public upstream package/release source and starts a local mock provider; it does not require this repository or any private fuzzing harness. The Docker run is limited to 2 CPUs and 4 GiB RAM by default.

Complete self-contained reproducer: https://gist.github.com/N0zoM1z0/1dfb1464c11634a0dbc0f51baac80fa8

The Gist contains qwen-repeated-identical-tool-call-loop.reproduce.py. Download and run:

gh gist clone 1dfb1464c11634a0dbc0f51baac80fa8 qwen-repeated-identical-tool-call-loop-reproducer
cd qwen-repeated-identical-tool-call-loop-reproducer
python3 qwen-repeated-identical-tool-call-loop.reproduce.py

To reuse an already-built local image:

python3 qwen-repeated-identical-tool-call-loop.reproduce.py --skip-build

Key output from a local run against the affected version:

process_exit=1
provider_requests=793
tool_result_counts={'repeat_loop_followup': 313010, 'repeat_loop_initial': 792}
late_stream_events_after_stop=0
side_effect_file_occurrences qwen-repeated-identical-tool-call-loop.log 'qwen-repeated-identical-tool-call-loop': observed=789 expected>=2
REPRODUCED