#27062 — Claude Sonnet 4.6 with medium thinking gets stuck in reasoning loop on Windows (PowerShell)

[ElioNeto]

Description

Title: Claude Sonnet 4.6 with medium thinking gets stuck in reasoning loop on Windows (PowerShell)

Body:

Description
When using Claude Sonnet 4.6 with medium thinking enabled, the model gets stuck in a loop where it plans and describes file changes entirely within the thinking/reasoning block but never executes the actual tool calls. Sometimes it even writes code inside the thinking trace instead of outputting it.

Environment

• OS: Windows (PowerShell)
• Model: claude-sonnet-4-6
• Thinking: medium
• OpenCode version: [1.14.48]

Steps to reproduce

1. Open a project in OpenCode
2. Select Claude Sonnet 4.6 with medium thinking
3. Ask the model to edit or refactor a file
4. Observe that changes are described in the thinking trace but no tool calls are executed

Expected behavior
Model completes thinking phase then executes tool calls to make the actual file changes.

Actual behavior
Model loops inside the thinking trace, planning changes but never acting on them. In some cases it writes code directly in the thinking block.

Related issues

• #15271
• #6176

Plugins

No response

OpenCode version

1.14.48

Steps to reproduce

Steps to reproduce

1. Open a project in OpenCode
2. Select Claude Sonnet 4.6 with medium thinking
3. Ask the model to edit or refactor a file
4. Observe that changes are described in the thinking trace but no tool calls are executed

Screenshot and/or share link

No response

Op

[Truncado — 1552 chars totais]

[ElioNeto]

Skipping — model-specific behavior issue (Claude Sonnet 4.6 thinking loop on Windows). Requires model-level investigation and potentially provider configuration changes. Needs manual triage.

[ElioNeto]

Skipping — requires manual triage. Unable to resolve automatically due to complexity, platform/API constraints, or insufficient information.