Gemini Interactions: Stateful Threads Through Rolter

Google exposes Gemini through three different surfaces. Rolter has a provider kind for each:

This page covers gemini_interactions.

Configuration#

[[providers]]name = "gemini-interactions"kind = "gemini_interactions"api_base = "https://generativelanguage.googleapis.com/v1beta"api_key_env = "GEMINI_API_KEY"

api_base points at the API version root — no /openai suffix and no /interactions suffix, Rolter appends that itself. The key is read from the environment (inline keys are rejected) and sent as x-goog-api-key, exactly as for gemini_native.

What Rolter translates#

Clients keep speaking their usual dialect. POST /v1/chat/completions, POST /v1/responses and POST /v1/messages are all mapped onto the single interactions endpoint.

Request

Response

The interaction’s steps[] are folded back into the client’s shape: model_output steps become assistant text, function_call steps become tool calls, and thought steps are dropped — reasoning traces are never surfaced as output. usage maps to the client’s token counters.

Streaming works the same way: interaction.created, step.start, step.delta and interaction.completed events are converted into OpenAI chunks, Anthropic message events, or Responses events depending on the endpoint the client called.

Threading a conversation#

The Interactions API keeps conversation history server-side. Rolter does not store interaction ids — the thread is client-driven, which keeps the gateway stateless and lets any replica serve the next turn.

The interaction id comes back as the response id. Send it on the next request as:

• previous_response_id — OpenAI Responses clients, where this field already exists
• previous_interaction_id — any dialect, passed through verbatim

# first turncurl -H "Authorization: Bearer $ROLTER_API_KEY" \  -H "Content-Type: application/json" \  -d '{"model":"gemini-3.6-flash","input":"Hi, my name is Phil."}' \  https://gateway.example.com/v1/responses# -> {"id": "int_123", ...}# second turn, resuming the same interactioncurl -H "Authorization: Bearer $ROLTER_API_KEY" \  -H "Content-Type: application/json" \  -d '{"model":"gemini-3.6-flash","previous_response_id":"int_123","input":"What is my name?"}' \  https://gateway.example.com/v1/responses

store is forwarded when set, so a client that opts out of retention keeps that control.

Unsupported endpoints#

The Interactions API only serves chat-shaped traffic. Requests to endpoints with no interactions equivalent — embeddings, audio — are rejected with a 400 gemini_interactions_unsupported error rather than being forwarded to an endpoint that cannot answer them. Route those models to a gemini or gemini_native provider instead.

Unsupported content parts#

Interactions carries a typed union of content parts. Rolter translates text / input_text and image_url / input_image; there is no opaque carrier for anything else.

A message containing a part rolter cannot translate — input_audio, a file or document part, or any new part type your client SDK starts sending — is rejected with 400 unsupported_content_part naming the part:

{  "error": {    "message": "the interactions upstream has no equivalent for content part type 'input_audio'; remove it or route this model to a provider that accepts it",    "type": "invalid_request_error",    "code": "unsupported_content_part",    "param": "messages"  }}

To send a modality Interactions cannot carry, route that model to a provider whose dialect supports it.