agentix 0.19.0

Multi-provider LLM client for Rust — streaming, non-streaming, tool calls, MCP, DeepSeek, OpenAI, Anthropic, Gemini
Documentation
pub mod request;
pub mod response;

use eventsource_stream::Eventsource;
use futures::{StreamExt, stream::BoxStream};
use tracing::debug;

use crate::config::AgentConfig;
use crate::error::ApiError;
use crate::msg::LlmEvent;
use crate::provider::{PostConfig, post_json, post_streaming};
use crate::raw::shared::ToolDefinition;
use crate::request::{Message, ToolCall};
use crate::types::{
    CompleteResponse, FinishReason, PartialToolCall, StreamBufs, ToolCallChunk, UsageStats,
};

use response::{ContentBlockDelta, ContentBlockStart, ResponseBlock, StreamEvent};

pub(crate) async fn stream_anthropic(
    token: &str,
    http: &reqwest::Client,
    config: &AgentConfig,
    messages: &[Message],
    tools: &[ToolDefinition],
) -> Result<BoxStream<'static, LlmEvent>, ApiError> {
    let req = request::build_anthropic_request(config, messages, tools, true);
    let url = format!("{}/v1/messages", config.base_url.trim_end_matches('/'));
    let resp = post_streaming(
        http,
        &url,
        &req,
        token,
        &PostConfig {
            use_query_key: false,
            auth_header: Some("x-api-key"),
            extra_headers: &[("anthropic-version", "2023-06-01")],
            max_retries: config.max_retries,
            retry_delay_ms: config.retry_delay_ms,
        },
    )
    .await?;

    Ok(async_stream::stream! {
        let mut bufs = StreamBufs::new();
        let mut sse  = resp.bytes_stream().eventsource();
        let mut saw_message_stop = false;

        while let Some(ev_res) = sse.next().await {
            match ev_res {
                Ok(ev) => {
                    #[cfg(feature = "sensitive-logs")]
                    if crate::sensitive_logs_enabled() {
                        tracing::info!(body = %ev.data, "received raw streaming response chunk");
                    }
                    if ev.data == "[DONE]" {
                        break;
                    }
                    match serde_json::from_str::<StreamEvent>(&ev.data) {
                        Ok(chunk) => {
                            if matches!(chunk, StreamEvent::MessageStop) {
                                saw_message_stop = true;
                            }
                            for lev in parse_stream_event(chunk, &mut bufs) { yield lev; }
                        }
                        Err(e) => {
                            debug!(data = %ev.data, error = %e, "anthropic chunk parse failed");
                        }
                    }
                }
                Err(e) => { yield LlmEvent::Error(e.to_string()); break; }
            }
        }
        if !saw_message_stop {
            yield LlmEvent::Error("stream ended without message_stop".to_string());
        }
        for tc in finalize(&mut bufs) { yield LlmEvent::ToolCall(tc); }
        yield LlmEvent::Done;
    }
    .boxed())
}

pub(crate) async fn complete_anthropic(
    token: &str,
    http: &reqwest::Client,
    config: &AgentConfig,
    messages: &[Message],
    tools: &[ToolDefinition],
) -> Result<CompleteResponse, ApiError> {
    let req = request::build_anthropic_request(config, messages, tools, false);
    let url = format!("{}/v1/messages", config.base_url.trim_end_matches('/'));
    let body = post_json(
        http,
        &url,
        &req,
        token,
        &PostConfig {
            use_query_key: false,
            auth_header: Some("x-api-key"),
            extra_headers: &[("anthropic-version", "2023-06-01")],
            max_retries: config.max_retries,
            retry_delay_ms: config.retry_delay_ms,
        },
    )
    .await?;

    let raw: response::Response = serde_json::from_str(&body).map_err(ApiError::Json)?;

    let mut content_buf = String::new();
    let mut reasoning_buf = String::new();
    let mut tool_calls = Vec::new();

    for block in raw.content {
        match block {
            ResponseBlock::Text { text } => content_buf.push_str(&text),
            ResponseBlock::Thinking { thinking } => reasoning_buf.push_str(&thinking),
            ResponseBlock::ToolUse { id, name, input } => {
                tool_calls.push(ToolCall {
                    id,
                    name,
                    arguments: serde_json::to_string(&input).unwrap_or_default(),
                });
            }
        }
    }

    Ok(CompleteResponse {
        content: if content_buf.is_empty() {
            None
        } else {
            Some(content_buf)
        },
        reasoning: if reasoning_buf.is_empty() {
            None
        } else {
            Some(reasoning_buf)
        },
        tool_calls,
        usage: raw.usage.map(UsageStats::from).unwrap_or_default(),
        finish_reason: raw
            .stop_reason
            .as_deref()
            .map(FinishReason::from)
            .unwrap_or_default(),
    })
}

fn parse_stream_event(ev: StreamEvent, bufs: &mut StreamBufs) -> Vec<LlmEvent> {
    match ev {
        StreamEvent::MessageStart { message } => {
            if let Some(u) = message.usage {
                return vec![LlmEvent::Usage(UsageStats::from(u))];
            }
            vec![]
        }
        StreamEvent::MessageDelta { usage, .. } => {
            if let Some(u) = usage {
                return vec![LlmEvent::Usage(UsageStats::from(u))];
            }
            vec![]
        }
        StreamEvent::ContentBlockStart {
            index,
            content_block,
        } => {
            let idx = index as usize;
            if bufs.tool_call_bufs.len() <= idx {
                bufs.tool_call_bufs.resize_with(idx + 1, || None);
            }
            match content_block {
                ContentBlockStart::ToolUse { id, name } => {
                    bufs.tool_call_bufs[idx] = Some(PartialToolCall {
                        id: id.clone(),
                        name: name.clone(),
                        arguments: String::new(),
                    });
                    vec![LlmEvent::ToolCallChunk(ToolCallChunk {
                        id,
                        name,
                        delta: String::new(),
                        index,
                    })]
                }
                ContentBlockStart::Text { text } if !text.is_empty() => {
                    bufs.content_buf.push_str(&text);
                    vec![LlmEvent::Token(text)]
                }
                ContentBlockStart::Thinking { thinking } if !thinking.is_empty() => {
                    bufs.reasoning_buf.push_str(&thinking);
                    vec![LlmEvent::Reasoning(thinking)]
                }
                _ => vec![],
            }
        }
        StreamEvent::ContentBlockDelta { index, delta } => match delta {
            ContentBlockDelta::TextDelta { text } if !text.is_empty() => {
                bufs.content_buf.push_str(&text);
                vec![LlmEvent::Token(text)]
            }
            ContentBlockDelta::ThinkingDelta { thinking } if !thinking.is_empty() => {
                bufs.reasoning_buf.push_str(&thinking);
                vec![LlmEvent::Reasoning(thinking)]
            }
            ContentBlockDelta::InputJsonDelta { partial_json } if !partial_json.is_empty() => {
                let idx = index as usize;
                if let Some(Some(partial)) = bufs.tool_call_bufs.get_mut(idx) {
                    partial.arguments.push_str(&partial_json);
                    vec![LlmEvent::ToolCallChunk(ToolCallChunk {
                        id: partial.id.clone(),
                        name: partial.name.clone(),
                        delta: partial_json,
                        index,
                    })]
                } else {
                    vec![]
                }
            }
            _ => vec![],
        },
        _ => vec![],
    }
}

fn finalize(bufs: &mut StreamBufs) -> Vec<ToolCall> {
    bufs.tool_call_bufs
        .drain(..)
        .flatten()
        .map(|p| ToolCall {
            id: p.id,
            name: p.name,
            arguments: p.arguments,
        })
        .collect()
}