Crate claude_stream 

Parse Anthropic’s Server-Sent Events stream into typed events.

No SDK dependency. Build it into whatever HTTP client / async runtime you already have: feed EventParser::feed bytes as they arrive, drain ready events with EventParser::next_event.

Quick start

use claude_stream::{EventParser, Event};

// Wire bytes Anthropic sent us:
let chunk = b"event: message_start\ndata: {\"type\":\"message_start\",\"message\":{\"id\":\"msg_1\",\"role\":\"assistant\"}}\n\nevent: content_block_delta\ndata: {\"type\":\"content_block_delta\",\"index\":0,\"delta\":{\"type\":\"text_delta\",\"text\":\"Hello\"}}\n\n";

let mut parser = EventParser::new();
parser.feed(chunk);

// Drain everything ready:
while let Some(event) = parser.next_event().unwrap() {
    match event {
        Event::MessageStart { message } => println!("started: {}", message.id),
        Event::ContentBlockDelta { delta, .. } => {
            if let claude_stream::Delta::TextDelta { text } = delta {
                print!("{text}");
            }
        }
        _ => {}
    }
}

Structs

EventParser

Incremental SSE parser for Anthropic’s messages stream.

Message

The message shell carried by Event::MessageStart.

MessageDelta

Top-level message delta.

Usage

Token usage. Field set evolves; we keep optional everywhere.

Enums

ContentBlock

One content block (passed by Event::ContentBlockStart).

Delta

One delta extending an in-progress content block.

Event

One Anthropic streaming event.

ParseError

Errors from parsing one event.