Describe the bug
While executing regular coding tasks that require file modifications, the Copilot CLI frequently fails to apply patches. The CLI enters a loop where it attempts to edit a file, fails with a JSON-wrapping error, and retries the exact same payload repeatedly.
This causes a task that should take 2 steps to take 30+ steps, resulting in massive latency, tool frustration, and high token consumption before it either randomly recovers or fails entirely.
Error Message / Trace
When the CLI attempts to apply an edit, it outputs the following error:
✗ Edit
└ Failed to parse patch: The first line of the patch must be '*** Begin Patch'
The input begins with '{' and appears to be JSON-wrapped. apply_patch is a
freeform tool; pass raw patch text directly. Do not retry this payload.
Behavior Details
Infinite Loop: Once this error is triggered, the model consistently retries the same payload 10 to 30+ times in a row despite the warning "Do not retry this payload".
Temporary Recovery: Eventually, the model might format the tool call correctly by accident, but the error quickly resurfaces on subsequent edits.
CLI vs. VS Code: This behavior is highly localized to the CLI. Using the same prompts and models in the VS Code Copilot Chat interface works perfectly without any patch-parsing issues.
Affected version
GitHub Copilot CLI 1.0.80
Steps to reproduce the behavior
This is intermittent but seen in most of medium complexity prompts.
- Open Terminal ( I did on iterm)
- start interactive session (copilot) - i did not append any flag options ( i opened a session on TMUX)
- Trigger a medium complexity prompt which would need to change your sourcecode files.
- It should trigger the error - It generally happens mid sessions not in the first prompt itself. but yea this is intermittent behaviour
Expected behavior
No response
Additional context
- OS: Ubuntu server
Tool: Github Copilot CLI (Latest Version)
Comparison: Not observed in VS Code Copilot Chat (works successfully there)
LLM Models tried : Both GPT-5.6-Luna and Claude-sonnet-5
Describe the bug
While executing regular coding tasks that require file modifications, the Copilot CLI frequently fails to apply patches. The CLI enters a loop where it attempts to edit a file, fails with a JSON-wrapping error, and retries the exact same payload repeatedly.
This causes a task that should take 2 steps to take 30+ steps, resulting in massive latency, tool frustration, and high token consumption before it either randomly recovers or fails entirely.
Error Message / Trace
When the CLI attempts to apply an edit, it outputs the following error:
Behavior Details
Infinite Loop: Once this error is triggered, the model consistently retries the same payload 10 to 30+ times in a row despite the warning "Do not retry this payload".
Temporary Recovery: Eventually, the model might format the tool call correctly by accident, but the error quickly resurfaces on subsequent edits.
CLI vs. VS Code: This behavior is highly localized to the CLI. Using the same prompts and models in the VS Code Copilot Chat interface works perfectly without any patch-parsing issues.
Affected version
GitHub Copilot CLI 1.0.80
Steps to reproduce the behavior
This is intermittent but seen in most of medium complexity prompts.
Expected behavior
No response
Additional context
Tool: Github Copilot CLI (Latest Version)
Comparison: Not observed in VS Code Copilot Chat (works successfully there)
LLM Models tried : Both GPT-5.6-Luna and Claude-sonnet-5