[Bug] Invalid model name accepted without validation error

Bug Description
I mistakenly ran claude --model sonnt in my shell and the Claude Code header actually said "sonnt with high effort"

Environment Info

• Platform: darwin
• Terminal: Apple_Terminal
• Version: 2.1.87
• Feedback ID: 52ef613e-2635-4a52-a650-9f824b7e5fd9

Errors

[{"error":"Error: NON-FATAL: Lock acquisition failed for /Users/mike/.local/share/claude/versions/2.1.87 (expected in multi-process scenarios)\n    at _p_ (/$bunfs/root/src/entrypoints/cli.js:2851:2138)\n    at Vn6 (/$bunfs/root/src/entrypoints/cli.js:2851:1218)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-03-30T06:18:22.030Z"},{"error":"Error: Plugin MCP server error - mcp-config-invalid: MCP server terraform invalid: Missing environment variables: TFE_TOKEN\n    at VzH (/$bunfs/root/src/entrypoints/cli.js:1820:37430)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-03-30T06:18:22.043Z"},{"error":"Error: Plugin MCP server error - mcp-config-invalid: MCP server terraform invalid: Missing environment variables: TFE_TOKEN\n    at VzH (/$bunfs/root/src/entrypoints/cli.js:1820:37430)\n    at async W (/$bunfs/root/src/entrypoints/cli.js:5827:10286)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-03-30T06:18:22.460Z"},{"error":"Error: Plugin MCP server error - mcp-config-invalid: MCP server terraform invalid: Missing environment variables: TFE_TOKEN\n    at VzH (/$bunfs/root/src/entrypoints/cli.js:1820:37430)\n    at async Z (/$bunfs/root/src/entrypoints/cli.js:5827:11056)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-03-30T06:18:22.461Z"}]