[BUG] Google models (Imagen, Nano Banana) fail due to steps parameter default value

[timoncool]

Description

Google provider models (Imagen 3/4, Nano Banana, Nano Banana 2) return an API error when called via imageInference because the steps parameter is always sent, even though these models do not support it.

Error

Error: Unsupported use of 'steps' parameter. This parameter is not supported for the selected model.

Root Cause

In runware_mcp_server.py, line 92:

steps: Optional[int] = 20,

The default value of 20 means steps is always included in the API request. Since optional_params filters by if value is not None (line 255), a default of 20 will never be None, so it's always sent to the API.

Google models (google:1@1, google:1@2, google:2@1, google:2@2, google:2@3, google:4@1, google:4@2, google:4@3) do not support the steps parameter and reject the request.

Affected Models

All models listed under https://runware.ai/docs/providers/google

Fix

Change the default from 20 to None:

# Before
steps: Optional[int] = 20,

# After
steps: Optional[int] = None,

This way steps will only be sent when explicitly provided by the user, and Google models will work correctly. Non-Google models will use their own server-side defaults.

The same issue may apply to the photoMaker function (line 299) which also has steps: Optional[int] = 20.

Environment

• MCP-Runware from main branch
• Claude Desktop / Claude Code
• Tested with models: google:4@1, google:4@3