fix: put filePath before content in write tool schema

[harmeet]

Issue for this PR

Closes #1498

Type of change

• Bug fix

What does this PR do?

The write tool schema defined content before filePath. Every other file tool (read, edit, apply_patch) puts filePath first. Small/quantized models are sensitive to property ordering in JSON schemas and use it as a positional cue — so with content first, they either omit filePath or get the key name wrong (e.g. producing file_path instead of filePath), causing:

Error: The write tool was called with invalid arguments: [
  {
    "expected": "string",
    "code": "invalid_type",
    "path": [
      "filePath"
    ],
    "message": "Invalid input: expected string, received undefined"
  }
]

The fix swaps the two parameters so filePath comes first, consistent with all other file tools.

How did you verify your code works?

Ran bun test test/tool/write.test.ts — 13/13 tests pass.

The bug only reproduces with a live small quantized model (originally observed with mlx-community/Qwen3-Coder-Next-4bit). The fix is a mechanical consistency change: filePath now comes first in the write tool schema, matching read, edit, and apply_patch.

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

[mapoit]

yes I can also see this error in qwen/qwen3.5-35b-a3b model with 4bit quantization.

[Rudd-O]

Can this please be merged? This is impacting us too.