Skip to main content
GoModel accepts OpenAI-compatible /v1/responses requests and routes them to the selected model provider. Some providers expose a native Responses-compatible surface. Others expose chat completions or provider-native chat APIs, so GoModel translates the request. The compatibility rule follows Postel’s Law: GoModel translates portable model features and accepts unfamiliar tool declarations without forwarding them to a provider that cannot execute them. Fields that would change the meaning of the model output are still rejected when they cannot be translated safely.

​
Routing modes

Chat-translated providers include Anthropic and Gemini native routing. They work well for text, streaming, multimodal inputs supported by the target adapter, and function tool loops. They cannot safely execute OpenAI-hosted tools.

​
Feature behavior

Anthropic does not currently accept translated response_format or text.verbosity settings through GoModel’s chat translation path. GoModel rejects those fields instead of dropping them.

​
The include field

include asks for extra annotations on response items, such as reasoning.encrypted_content or file_search_call.results. It never changes what the model does, so chat-translated providers accept it and return a response without those annotations, exactly like a native provider that does not support them. Clients that always attach include, such as Codex with wire_api = "responses", work without extra configuration. The one exception is message.output_text.logprobs, which requests real model output rather than an annotation. GoModel rejects it for the same reason it rejects top_logprobs.

​
Hosted tools

Hosted tools are executed by the upstream provider, not by the model text completion alone. Their payloads often reference provider-owned resources and runtime state:
  • web_search and its legacy web_search_preview alias depend on the provider’s search implementation and event schema.
  • file_search references provider vector stores such as vector_store_ids.
  • computer_use_preview depends on a provider-managed computer session, display environment, and safety model.
GoModel does not translate these into Anthropic, Gemini, or other chat-provider tool calls. A fake translation would change where the tool runs, how state is stored, and which security controls apply. Chat-translated providers therefore accept the request but omit every non-function tool before provider dispatch. Supported function tools in the same request continue to work normally. namespace tools are omitted as a unit rather than flattened. Flattening would change the tool names and break the client’s routing contract. A tool_choice that selects an omitted tool is omitted too. If every tool is omitted, parallel_tool_calls is also removed from the translated request. This is graceful capability degradation, not hosted-tool emulation. In particular, a response from a chat-translated provider does not imply that a web search, file search, or computer action occurred. Use a native Responses provider when the result depends on one of those tools running.

​
Agent SDKs

OpenAI Agents SDK clients can talk to Anthropic and Gemini models through GoModel for portable flows:
  • plain Runner.run(...)
  • Runner.run_streamed(...) over HTTP/SSE
  • local function tools
  • SDK-managed local history replay
Provider-hosted tools are ignored by chat-translated providers. Server-managed conversation state and websocket Responses transport still depend on provider-specific support. For Python Agents SDK clients, namespaced GoModel model IDs such as anthropic/claude-sonnet-4-20250514 and gemini/gemini-2.0-flash need model ID pass-through mode:
Use that run_config when calling Runner.run(...) or Runner.run_streamed(...).

​
Test the compatibility boundary

The OpenAI Agents SDK examples include probes for Anthropic routing through GoModel:
The Responses probe verifies both supported and unsupported paths: plain Responses calls, function tools, structured-output rejection, stateful-field rejection, unknown input-item rejection, and graceful hosted-tool omission. The Agents probe verifies basic runs, function tool loops, and streamed function tool loops.

​
Roadmap

Future support for hosted tools should use explicit provider capability mapping. That means GoModel should know which provider, model, API mode, and request shape can safely handle each feature before accepting the request.
Last modified on August 1, 2026