[Kinfe123]

Problem

Mistral's Responses API uses OpenAI-style tool events, but passing an @mistralai/mistralai@3.4.0 stream directly to streamfold/openai produces no updates. Unwrapping frame.data alone still drops argument deltas and ends with EMPTY_INPUT, because the SDK converts the wire's item_id to itemId.

Root cause

The existing adapter consumes decoded OpenAI events with snake-case argument identifiers. Mistral's SDK exposes a frame envelope and camel-case identifiers.

Change

Add a small copyable example that unwraps the frame, normalizes the two argument-event identifiers, and delegates to the existing OpenAI adapter through readStructured. It preserves immutable previews and managed iterator cleanup without introducing another stateful adapter.

Add the Mistral SDK as a development dependency for real decoder and consumer-type coverage. The published package gains no dependencies or exports. Document use, item IDs, cancellation, and the application-owned validation and response-status responsibilities.

Verification

• node --test examples/mistral.test.mjs: both cases pass. The real SDK decodes wire SSE into interleaved calls; assertions cover IDs, final values, retained immutable partial values, and cancelling the response body on early exit.
• Removing only the itemId conversion makes the interleaved replay fail with EMPTY_INPUT for call a; restoring it passes.
• pnpm typecheck: passes, including a consumer of the actual client.responses.create() return type.
• pnpm release:check: passes, including 199 JavaScript tests, 11 Rust tests, syntax/type checks, Rust formatting/lints, and package dry run.

No credentials or live model requests were used. This PR makes no end-to-end performance claim.

Public surface

Documentation and an example only. No published source, declarations, exports, or runtime dependencies change.

[Kinfe123]

lgtm, mistral sdk frames reuse the adapter with tested cleanup.