If you're on opencode's go $10/mo plan and want to use GLM-5.3-flash right now on pi, you can add this to models.json until pi updates to support it:

    {
      "providers": {
        "opencode-go": {
          "models": [
            {
              "id": "glm-5.3-flash",
              "name": "GLM-5.3 Flash",
              "api": "openai-completions",
              "baseUrl": "https://opencode.ai/zen/go/v1",
              "reasoning": true,
              "input": ["text", "image"],
              "cost": {
                "input": 0.15,
                "output": 0.5,
                "cacheRead": 0.03,
                "cacheWrite": 0
              },
              "compat": {
                "supportsStore": false,
                "supportsDeveloperRole": false,
                "maxTokensField": "max_tokens"
              },
              "contextWindow": 1000000,
              "maxTokens": 131072,
              "thinkingLevelMap": {
                "off": null,
                "minimal": null,
                "low": "low",
                "medium": null,
                "high": "high",
                "xhigh": null,
                "max": "max"
              }
            }
          ]
        }
      }
    }

For openrouter in pi:

{ "providers": { "openrouter": { "models": [ { "id": "z-ai/glm-5.3-flash", "name": "Z.ai: GLM 5.3 Flash", "reasoning": true, "thinkingLevelMap": { "off": null, "minimal": null, "low": "low", "medium": null, "high": "high", "xhigh": null, "max": "max" }, "input": ["text", "image"], "cost": { "input": 0.075, "output": 0.25, "cacheRead": 0.015, "cacheWrite": 0 }, "contextWindow": 1048576, "maxTokens": 131072 } ] } } }