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Providers Overview

No configuration needed — these endpoints work the moment the binary starts. Every response is rendered from a bundled Tera template that you can override (see Overriding bundled defaults).

Provider Endpoint Streaming
OpenAI Chat POST /v1/chat/completions ✅
OpenAI Responses POST /v1/responses ✅ (typed SSE events)
OpenAI Embeddings POST /v1/embeddings —
OpenAI Images POST /v1/images/generations —
OpenAI Moderations POST /v1/moderations —
Anthropic POST /v1/messages ✅ (all 7 SSE event types)
Gemini Generate POST /v1beta/models/*:generateContent ✅ (text deltas + terminal finishReason: STOP chunk, no [DONE])
Gemini Embeddings POST /v1beta/models/*:embedContent —
Gemini Token Count POST /v1beta/models/*:countTokens —
Gemini Models GET /v1beta/models —
Gemini OpenAI Shim /v1beta/openai/* ✅
Azure OpenAI POST /openai/deployments/* ✅
Bedrock POST /model/*/invoke ✅
Vertex AI POST /v1/projects/*/...:generateContent ✅
Cohere, Mistral, Groq OpenAI-compatible ✅
Error Simulator ANY /error/{code} —

Beyond the basics

  • Tool calling — OpenAI tool_calls, Anthropic tool_use, Gemini functionCall. The response echoes the caller's declared tool name. See Tool calling.
  • Agentic loop termination — when a tool result is already in the request history, the mock switches to a plain-text answer instead of looping another tool call. See Agentic testing.
  • Reasoning model tokens — o-series models return completion_tokens_details.reasoning_tokens.
  • Gemini 2.5 fidelity — thoughtsTokenCount, promptTokensDetails, modelVersion, responseId.
  • Anthropic cost fields — cache_creation, service_tier, inference_geo, stop_details.

Provider deep-dives