0.1 — 2026-04-06

Initial release of the OCaml AI SDK — a type-safe, provider-agnostic AI model abstraction inspired by the Vercel AI SDK, targeting AI SDK v6 wire compatibility.

Provider Abstraction Layer (ai_provider)

• Extensible GADT-based Provider_options for compile-time type-safe provider-specific settings
• Role-constrained Prompt types (System = string only, User = text + files, etc.)
• Language_model.S module type with first-class module wrapper
• Tool, Tool_choice, Mode, Content foundation types
• Finish_reason, Usage, Warning, Provider_error types
• Provider.S and Middleware.S module type signatures
• Call_options, Generate_result, Stream_part, Stream_result types

Anthropic Provider (ai_provider_anthropic)

• Full Anthropic Messages API implementation with streaming (SSE)
• Thinking support with budget_tokens smart constructor (>= 1024)
• Cache_control for prompt caching
• Anthropic_options via the extensible GADT system
• Model catalog with all Claude models (Opus, Sonnet, Haiku families)
• Beta header management and model-aware max_tokens
• Prompt conversion with message grouping, tool conversion, response parsing
• Provider factory and public API

OpenAI Provider (ai_provider_openai)

• OpenAI Chat Completions API implementation with streaming (SSE)
• Model catalog with GPT-4o, GPT-4o-mini, o1, o3, o4-mini families
• Tool calling with strict mode support
• Prompt conversion, response parsing, and provider factory

Core SDK (ai_core)

• generate_text — synchronous text generation with multi-step tool loop
• stream_text — streaming text generation with multi-step tool loop, returns synchronously with streams filled by background Lwt task
• Output API — Output.text, Output.object_, Output.enum, Output.array, Output.choice with JSON Schema validation
• UIMessage stream protocol — SSE data: {json}\n\n encoding with x-vercel-ai-ui-message-stream: v1 header, all v6 chunk types
• Ui_message_stream_writer — composable stream builder with write (synchronous) and merge (non-blocking via Lwt.async), lifecycle management, ref-counted in-flight merge tracking, on_finish callback
• Server handler — cohttp endpoint for chat with CORS support, v6-only request parsing with full part type support (text, file, reasoning, tool invocations with all states)
• Tool approval workflow — needs_approval predicate on Core_tool.t, step loop partitioning, Tool_approval_request chunk type, stateless re-submission with approved_tool_call_ids
• Stop_condition — step loop termination predicates matching upstream stopWhen: step_count_is, has_tool_call, is_met (OR semantics with short-circuit); wired through generate_text, stream_text, and server_handler; max_steps remains as independent hard safety cap
• Partial JSON parser — for streaming structured output

Melange Bindings (ai-sdk-react)

• useChat and useCompletion hook bindings for @ai-sdk/react
• All v6 message part types including data_ui_part
• classify function for part type dispatch
• Module-scoped accessors for ergonomic use from OCaml/Reason

Examples

• one_shot, streaming, tool_use, thinking, generate, stream_chat, agent_loop — standalone CLI examples
• chat_server — cohttp chat server with React frontend, tool approval, structured output
• custom_stream — custom data streaming with Melange frontend
• ai-e2e — end-to-end Melange app with 11 demos (basic chat, reasoning, tool use, tool approval, client tools, file attachments, structured output, completion, web search, retry/regenerate)

Infrastructure

• Dune build with generate_opam_files for automated opam file generation
• mlx dialect support (OCaml + JSX via mlx-pp / ocamlformat-mlx)
• Alcotest test suites for all three libraries
• SSE wire format snapshot tests