[MODEL] MCP tools do not respond or run on haiku 4.5

Preflight Checklist

• [x] I have searched existing issues for similar behavior reports
• [x] This report does NOT contain sensitive information (API keys, passwords, etc.)

Type of Behavior Issue

Claude ignored my instructions or configuration

What You Asked Claude to Do

Get a list of tasks in Asana

What Claude Actually Did

The tool to get the list of tasks in Asana was not executed and an irrelevant answer was given immediately.

Expected Behavior

Use the Asana MCP tool to get a list of tasks

Files Affected

Permission Mode

I don't know / Not sure

Can You Reproduce This?

Yes, every time with the same prompt

Steps to Reproduce

_No response_

Claude Model

Haiku

Relevant Conversation

Impact

High - Significant unwanted changes

Claude Code Version

2.0.22 (Claude Code)

Platform

Anthropic API

Additional Context

Rather than being a bug, I would like to know if this is because the MCP tool does not run due to the model not being able to make deep inferences, which is a characteristic of Haiku.

We are currently developing an MCP server, and we expect free users of Claude to also use it. Therefore, if free users cannot use Sonnet, we thought that the MCP server would not be able to be used with Haiku.