i would recommend getting an API account on fireworks, this is ZDR and typically the fastest provider.

otherwise check the list of providers on openrouter and you can see the pricing, quantisation, sign up directly rather than via a router. ensure to get caching prices, do not get input/output API prices.

GLM 5 is a frontier model, Kimi 2.5 is similar with vision support, Minimax M2.7 is a very capable model focused on tool calling.

If you need server side web search, you could use the Z AI API directly, again ZDR; or Friendli AI; or just install a search mcp.

For the harness opencode is the normal one, it has subagents and parallel tool calling; or just use claude code by pointing it at the anthropic APIs of various providers like fireworks.