Repository navigation
Write tool JSON parsing error with large files and special characters #11630
Description
Bug Description
The Write tool consistently fails with JSON parsing errors when writing files that contain:
- Large content (>~1000 characters)
- Special characters (quotes, newlines, backticks)
- Code blocks with nested structures
Error Messages
Common errors encountered:
JSON Parse error: Unterminated stringInvalid input for tool write: JSON parsing failedJSON Parse error: Expected ']'
Reproduction Steps
- Try to write a Rust file with ~200+ lines using the Write tool
- Content includes code with quotes, backticks, or special characters
- Error occurs consistently
Example that fails:
/// Fixed-point arithmetic module (16.16 format)
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct Fixed(i32);
impl Fixed {
const FRACTIONAL_BITS: i32 = 16;
// ... more code with quotes and special chars
}Workaround
Using bash with heredoc works reliably:
cat > /path/to/file.rs << 'EOF'
// Large file content here
// With any special characters
EOFEnvironment
- Platform: macOS (darwin)
- Model: kimi-k2.5-free
- Working with: Rust code files, Markdown documentation
Impact
- Must use bash workarounds for any substantial file writes
- Breaks flow when editing multiple files
- Limits ability to use Write tool effectively
Suggested Fix
Either:
- Increase JSON string size limits
- Better escaping for special characters
- Alternative write method for large files
- Document the limitation and recommend bash for large files
Metadata
Metadata
Assignees
Labels
No labels
Activity
github-actions commentedon Feb 1, 2026
This issue might be a duplicate of existing issues. Please check:
Error message: JSON Parse error: Unterminated stringerrors #10755: JSON Parse error: Unterminated string errors with Write toolFeel free to ignore if none of these address your specific case.
fix: properly encode file URLs with special characters (anomalyco#11790)
fix: properly encode file URLs with special characters (anomalyco#11790)
github-actions commentedon Apr 3, 2026
To stay organized issues are automatically closed after 90 days of no activity. If the issue is still relevant please open a new one.