[BUG] Missing Tools should be surfaced as a hard blocker

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Missing MCP tools should be surfaced as a hard blocker when a task explicitly depends on them, not discovered through failed fetches
Credits spent on a session that couldn't fulfill the stated requirement due to environment misconfiguration

What Should Happen?

Action should stop when it realizes it doesn't have the tools and user gets reimbursed for the credits wasted if it continues with the action

Error Messages/Logs

Steps to Reproduce

Missing MCP tools should be surfaced as a hard blocker when a task explicitly depends on them, not discovered through failed fetches
Credits spent on a session that couldn't fulfill the stated requirement due to environment misconfiguration

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

4.6

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Windows Terminal

Additional Information

_No response_