claude-code - 💡(How to fix) Fix WebFetch tool fails with "model not found" due to invalid model ID format (@ instead of -) [1 comments, 2 participants]

The WebFetch tool fails on invocation with the following error: 2. The tool fails immediately before fetching any content with the model error above. Tool returns an error and does not fetch the URL.

• Model in use at time of error: claude-sonnet-4-6 (1M context)
• The error originates from the WebFetch tool's internal model selection, not the session model

TL;DR

Update the WebFetch tool's internal model ID to use hyphens instead of the @ delimiter.

Guidance

• Verify the model ID format in the Anthropic model list to ensure it matches the expected format of hyphens throughout, without the @ sign.
• Check the WebFetch tool's configuration to identify where the model ID is specified and update it to the correct format, e.g., claude-haiku-4-5-20251001.
• Test the WebFetch tool with the updated model ID to ensure it can successfully fetch and process URL content.
• If the issue persists, try selecting a different model using the /model command to rule out any model-specific issues.

Example

No code snippet is provided as the issue is related to configuration and model ID formatting.

Notes

The solution assumes that the WebFetch tool allows for configuration updates and that the model ID is the only issue causing the error.

Recommendation

Apply workaround: Update the model ID in the WebFetch tool's configuration to use the correct format, as the tool's internal configuration appears to be the root cause of the issue.