How to use GLM-5.1 in Claude Code
z.ai has released GLM 5.1 which according to benchmark is top coding model which performs well slightly below Claude Opus 4.6.
It is now available in all GLM Coding Plan and via their API as well.
To use it in Claude Code, you need to update the model id in claude settings ~/.claude/settings.json
{
"env": {
"ANTHROPIC_AUTH_TOKEN": "$ZAI_API_KEY",
"ANTHROPIC_BASE_URL": "https://api.z.ai/api/anthropic",
"API_TIMEOUT_MS": "3000000",
"ANTHROPIC_DEFAULT_HAIKU_MODEL": "glm-4.5-air",
"ANTHROPIC_DEFAULT_SONNET_MODEL": "glm-5.1",
"ANTHROPIC_DEFAULT_OPUS_MODEL": "glm-5.1"
}
}