Module items 

Cross-dialect canonical representation.

The central model is content items — a typed, ordered list per message. Anthropic Messages, OpenAI Responses, and Gemini all share this shape natively; OpenAI Chat/Completions is the only dialect that hoists tool calls into a side-array, and that asymmetry is normalized at the dialect adapter boundary.

Invariants enforced here:

• ItemStreamMessage.items preserves order verbatim from the wire.
• ToolCall.id is non-empty; ToolResult.tool_call_id references a prior ToolCall in the same conversation.
• Thinking.signature is opaque and never fabricated; None propagates as None through dialects that support unsigned thinking (all except Anthropic-signed).
• Text("") is legal in the model; dropping happens in dialect code (Gemini rejects empty parts upstream).

Lossy notes are documented per-dialect; the canonical model itself stays lossless.

Structs

ItemMeta

ItemRequest

ItemStreamMessage

ThinkingCfg

Tool

Enums

ContentItem

ResponseFormat

Role

ToolChoice