Backend: Add Anthropic/Claude provider integration

- Add anthropic.rs module with streaming support
- Convert between internal and Anthropic tool/message formats
- Add keyring dependency for secure API key storage
- Add API key management commands (get_exists, set)
- Auto-detect provider from model name (claude-* prefix)
- Support SSE streaming from Anthropic API
- Handle tool calling with Anthropic's format
- Add cancellation support for Anthropic streams

src-tauri/Cargo.lock

@@ -960,6 +960,17 @@ dependencies = [
  "pin-project-lite",
 ]
 
+[[package]]
+name = "eventsource-stream"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "74fef4569247a5f429d9156b9d0a2599914385dd189c539334c625d8099d90ab"
+dependencies = [
+ "futures-core",
+ "nom",
+ "pin-project-lite",
+]
+
 [[package]]
 name = "fastrand"
 version = "2.3.0"
@@ -1988,6 +1999,16 @@ dependencies = [
  "unicode-segmentation",
 ]
 
+[[package]]
+name = "keyring"
+version = "3.6.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "eebcc3aff044e5944a8fbaf69eb277d11986064cba30c468730e8b9909fb551c"
+dependencies = [
+ "log",
+ "zeroize",
+]
+
 [[package]]
 name = "kuchikiki"
 version = "0.8.8-speedreader"
@@ -2074,8 +2095,10 @@ version = "0.1.0"
 dependencies = [
  "async-trait",
  "chrono",
+ "eventsource-stream",
  "futures",
  "ignore",
+ "keyring",
  "reqwest",
  "serde",
  "serde_json",
@@ -2162,6 +2185,12 @@ version = "0.3.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6877bb514081ee2a7ff5ef9de3281f14a4dd4bceac4c09388074a6b5df8a139a"
 
+[[package]]
+name = "minimal-lexical"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "68354c5c6bd36d73ff3feceb05efa59b6acb7626617f4962be322a825e61f79a"
+
 [[package]]
 name = "miniz_oxide"
 version = "0.8.9"
@@ -2276,6 +2305,16 @@ version = "0.1.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "72ef4a56884ca558e5ddb05a1d1e7e1bfd9a68d9ed024c21704cc98872dae1bb"
 
+[[package]]
+name = "nom"
+version = "7.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d273983c5a657a70a3e8f2a01329822f3b8c8172b73826411a55751e404a0a4a"
+dependencies = [
+ "memchr",
+ "minimal-lexical",
+]
+
 [[package]]
 name = "num-conv"
 version = "0.1.0"

src-tauri/Cargo.toml

@@ -32,3 +32,5 @@ chrono = { version = "0.4.42", features = ["serde"] }
 async-trait = "0.1.89"
 tauri-plugin-store = "2.4.1"
 tokio = { version = "1", features = ["sync"] }
+keyring = "3.2"
+eventsource-stream = "0.2.3"

src-tauri/src/commands/chat.rs

@@ -1,4 +1,5 @@
 use crate::commands::{fs, search, shell};
+use crate::llm::anthropic::AnthropicProvider;
 use crate::llm::ollama::OllamaProvider;
 use crate::llm::prompts::SYSTEM_PROMPT;
 use crate::llm::types::{Message, Role, ToolCall, ToolDefinition, ToolFunctionDefinition};
@@ -23,6 +24,35 @@ pub async fn get_ollama_models(base_url: Option<String>) -> Result<Vec<String>,
     OllamaProvider::get_models(&url).await
 }
 
+#[tauri::command]
+pub async fn get_anthropic_api_key_exists() -> Result<bool, String> {
+    match keyring::Entry::new("living-spec-anthropic-api-key", "default") {
+        Ok(entry) => Ok(entry.get_password().is_ok()),
+        Err(e) => Err(format!("Failed to access keychain: {}", e)),
+    }
+}
+
+#[tauri::command]
+pub async fn set_anthropic_api_key(api_key: String) -> Result<(), String> {
+    let entry = keyring::Entry::new("living-spec-anthropic-api-key", "default")
+        .map_err(|e| format!("Failed to create keychain entry: {}", e))?;
+
+    entry
+        .set_password(&api_key)
+        .map_err(|e| format!("Failed to store API key: {}", e))?;
+
+    Ok(())
+}
+
+fn get_anthropic_api_key() -> Result<String, String> {
+    let entry = keyring::Entry::new("living-spec-anthropic-api-key", "default")
+        .map_err(|e| format!("Failed to access keychain: {}", e))?;
+
+    entry
+        .get_password()
+        .map_err(|_| "Anthropic API key not found. Please set your API key.".to_string())
+}
+
 #[tauri::command]
 pub async fn chat(
     app: AppHandle,
@@ -46,12 +76,13 @@ pub async fn chat(
         .clone()
         .unwrap_or_else(|| "http://localhost:11434".to_string());
 
-    if config.provider.as_str() != "ollama" {
+    // Determine provider from model name
+    let is_claude = config.model.starts_with("claude-");
+
+    if !is_claude && config.provider.as_str() != "ollama" {
         return Err(format!("Unsupported provider: {}", config.provider));
     }
 
-    let provider = OllamaProvider::new(base_url);
-
     // 2. Define Tools
     let tool_defs = get_tool_definitions();
     let tools = if config.enable_tools.unwrap_or(true) {
@@ -100,10 +131,22 @@ pub async fn chat(
         turn_count += 1;
 
         // Call LLM with streaming
-        let response = provider
+        let response = if is_claude {
-            .chat_stream(&app, &config.model, &current_history, tools, &mut cancel_rx)
+            // Use Anthropic provider
-            .await
+            let api_key = get_anthropic_api_key()?;
-            .map_err(|e| format!("LLM Error: {}", e))?;
+            let anthropic_provider = AnthropicProvider::new(api_key);
+            anthropic_provider
+                .chat_stream(&app, &config.model, &current_history, tools, &mut cancel_rx)
+                .await
+                .map_err(|e| format!("Anthropic Error: {}", e))?
+        } else {
+            // Use Ollama provider
+            let ollama_provider = OllamaProvider::new(base_url.clone());
+            ollama_provider
+                .chat_stream(&app, &config.model, &current_history, tools, &mut cancel_rx)
+                .await
+                .map_err(|e| format!("Ollama Error: {}", e))?
+        };
 
         // Process Response
         if let Some(tool_calls) = response.tool_calls {

src-tauri/src/lib.rs

@@ -24,7 +24,9 @@ pub fn run() {
             commands::shell::exec_shell,
             commands::chat::chat,
             commands::chat::get_ollama_models,
-            commands::chat::cancel_chat
+            commands::chat::cancel_chat,
+            commands::chat::get_anthropic_api_key_exists,
+            commands::chat::set_anthropic_api_key
         ])
         .run(tauri::generate_context!())
         .expect("error while running tauri application");

src-tauri/src/llm/anthropic.rs

@@ -0,0 +1,336 @@
+use crate::llm::types::{
+    CompletionResponse, FunctionCall, Message, Role, ToolCall, ToolDefinition,
+};
+use futures::StreamExt;
+use reqwest::header::{HeaderMap, HeaderValue, CONTENT_TYPE};
+use serde::{Deserialize, Serialize};
+use serde_json::json;
+use tauri::{AppHandle, Emitter};
+use tokio::sync::watch::Receiver;
+
+const ANTHROPIC_API_URL: &str = "https://api.anthropic.com/v1/messages";
+const ANTHROPIC_VERSION: &str = "2023-06-01";
+
+pub struct AnthropicProvider {
+    api_key: String,
+    client: reqwest::Client,
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+struct AnthropicMessage {
+    role: String, // "user" or "assistant"
+    content: AnthropicContent,
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+#[serde(untagged)]
+enum AnthropicContent {
+    Text(String),
+    Blocks(Vec<AnthropicContentBlock>),
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+#[serde(tag = "type")]
+enum AnthropicContentBlock {
+    #[serde(rename = "text")]
+    Text { text: String },
+    #[serde(rename = "tool_use")]
+    ToolUse {
+        id: String,
+        name: String,
+        input: serde_json::Value,
+    },
+    #[serde(rename = "tool_result")]
+    ToolResult {
+        tool_use_id: String,
+        content: String,
+    },
+}
+
+#[derive(Debug, Serialize)]
+struct AnthropicTool {
+    name: String,
+    description: String,
+    input_schema: serde_json::Value,
+}
+
+#[derive(Debug, Deserialize)]
+struct StreamEvent {
+    #[serde(rename = "type")]
+    event_type: String,
+    #[serde(flatten)]
+    data: serde_json::Value,
+}
+
+impl AnthropicProvider {
+    pub fn new(api_key: String) -> Self {
+        Self {
+            api_key,
+            client: reqwest::Client::new(),
+        }
+    }
+
+    /// Convert our internal tool definitions to Anthropic format
+    fn convert_tools(tools: &[ToolDefinition]) -> Vec<AnthropicTool> {
+        tools
+            .iter()
+            .map(|tool| AnthropicTool {
+                name: tool.function.name.clone(),
+                description: tool.function.description.clone(),
+                input_schema: tool.function.parameters.clone(),
+            })
+            .collect()
+    }
+
+    /// Convert our internal messages to Anthropic format
+    fn convert_messages(messages: &[Message]) -> Vec<AnthropicMessage> {
+        let mut anthropic_messages: Vec<AnthropicMessage> = Vec::new();
+
+        for msg in messages {
+            match msg.role {
+                Role::System => {
+                    // Anthropic doesn't support system messages in the messages array
+                    // They should be passed separately in the 'system' parameter
+                    // For now, we'll skip them or convert to user messages
+                    continue;
+                }
+                Role::User => {
+                    anthropic_messages.push(AnthropicMessage {
+                        role: "user".to_string(),
+                        content: AnthropicContent::Text(msg.content.clone()),
+                    });
+                }
+                Role::Assistant => {
+                    if let Some(tool_calls) = &msg.tool_calls {
+                        // Assistant message with tool calls
+                        let mut blocks = Vec::new();
+
+                        // Add text content if present
+                        if !msg.content.is_empty() {
+                            blocks.push(AnthropicContentBlock::Text {
+                                text: msg.content.clone(),
+                            });
+                        }
+
+                        // Add tool use blocks
+                        for call in tool_calls {
+                            let input: serde_json::Value =
+                                serde_json::from_str(&call.function.arguments).unwrap_or(json!({}));
+
+                            blocks.push(AnthropicContentBlock::ToolUse {
+                                id: call
+                                    .id
+                                    .clone()
+                                    .unwrap_or_else(|| uuid::Uuid::new_v4().to_string()),
+                                name: call.function.name.clone(),
+                                input,
+                            });
+                        }
+
+                        anthropic_messages.push(AnthropicMessage {
+                            role: "assistant".to_string(),
+                            content: AnthropicContent::Blocks(blocks),
+                        });
+                    } else {
+                        // Regular assistant message
+                        anthropic_messages.push(AnthropicMessage {
+                            role: "assistant".to_string(),
+                            content: AnthropicContent::Text(msg.content.clone()),
+                        });
+                    }
+                }
+                Role::Tool => {
+                    // Tool result - needs to be sent as a user message with tool_result content
+                    let tool_use_id = msg.tool_call_id.clone().unwrap_or_default();
+                    anthropic_messages.push(AnthropicMessage {
+                        role: "user".to_string(),
+                        content: AnthropicContent::Blocks(vec![
+                            AnthropicContentBlock::ToolResult {
+                                tool_use_id,
+                                content: msg.content.clone(),
+                            },
+                        ]),
+                    });
+                }
+            }
+        }
+
+        anthropic_messages
+    }
+
+    /// Extract system prompt from messages
+    fn extract_system_prompt(messages: &[Message]) -> String {
+        messages
+            .iter()
+            .filter(|m| matches!(m.role, Role::System))
+            .map(|m| m.content.as_str())
+            .collect::<Vec<_>>()
+            .join("\n\n")
+    }
+
+    pub async fn chat_stream(
+        &self,
+        app: &AppHandle,
+        model: &str,
+        messages: &[Message],
+        tools: &[ToolDefinition],
+        cancel_rx: &mut Receiver<bool>,
+    ) -> Result<CompletionResponse, String> {
+        // Convert messages and tools
+        let anthropic_messages = Self::convert_messages(messages);
+        let anthropic_tools = Self::convert_tools(tools);
+        let system_prompt = Self::extract_system_prompt(messages);
+
+        // Build request
+        let mut request_body = json!({
+            "model": model,
+            "max_tokens": 4096,
+            "messages": anthropic_messages,
+            "stream": true,
+        });
+
+        if !system_prompt.is_empty() {
+            request_body["system"] = json!(system_prompt);
+        }
+
+        if !anthropic_tools.is_empty() {
+            request_body["tools"] = json!(anthropic_tools);
+        }
+
+        // Build headers
+        let mut headers = HeaderMap::new();
+        headers.insert(CONTENT_TYPE, HeaderValue::from_static("application/json"));
+        headers.insert(
+            "x-api-key",
+            HeaderValue::from_str(&self.api_key).map_err(|e| e.to_string())?,
+        );
+        headers.insert(
+            "anthropic-version",
+            HeaderValue::from_static(ANTHROPIC_VERSION),
+        );
+
+        // Make streaming request
+        let response = self
+            .client
+            .post(ANTHROPIC_API_URL)
+            .headers(headers)
+            .json(&request_body)
+            .send()
+            .await
+            .map_err(|e| format!("Failed to send request to Anthropic: {}", e))?;
+
+        if !response.status().is_success() {
+            let status = response.status();
+            let error_text = response
+                .text()
+                .await
+                .unwrap_or_else(|_| "Unknown error".to_string());
+            return Err(format!("Anthropic API error {}: {}", status, error_text));
+        }
+
+        // Process streaming response
+        let mut stream = response.bytes_stream();
+        let mut accumulated_text = String::new();
+        let mut tool_calls: Vec<ToolCall> = Vec::new();
+        let mut current_tool_use: Option<(String, String, String)> = None; // (id, name, input_json)
+
+        loop {
+            let chunk = tokio::select! {
+                result = stream.next() => {
+                    match result {
+                        Some(c) => c,
+                        None => break,
+                    }
+                }
+                _ = cancel_rx.changed() => {
+                    if *cancel_rx.borrow() {
+                        return Err("Chat cancelled by user".to_string());
+                    }
+                    continue;
+                }
+            };
+
+            let bytes = chunk.map_err(|e| format!("Stream error: {}", e))?;
+            let text = String::from_utf8_lossy(&bytes);
+
+            // Parse SSE events
+            for line in text.lines() {
+                if let Some(json_str) = line.strip_prefix("data: ") {
+                    // Remove "data: " prefix
+
+                    if json_str == "[DONE]" {
+                        break;
+                    }
+
+                    let event: StreamEvent = match serde_json::from_str(json_str) {
+                        Ok(e) => e,
+                        Err(_) => continue,
+                    };
+
+                    match event.event_type.as_str() {
+                        "content_block_start" => {
+                            // Check if this is a tool use block
+                            if let Some(content_block) = event.data.get("content_block") {
+                                if content_block.get("type") == Some(&json!("tool_use")) {
+                                    let id = content_block["id"].as_str().unwrap_or("").to_string();
+                                    let name =
+                                        content_block["name"].as_str().unwrap_or("").to_string();
+                                    current_tool_use = Some((id, name, String::new()));
+                                }
+                            }
+                        }
+                        "content_block_delta" => {
+                            if let Some(delta) = event.data.get("delta") {
+                                // Text delta
+                                if delta.get("type") == Some(&json!("text_delta")) {
+                                    if let Some(text) = delta.get("text").and_then(|t| t.as_str()) {
+                                        accumulated_text.push_str(text);
+                                        // Emit token to frontend
+                                        let _ = app.emit("chat:token", text);
+                                    }
+                                }
+                                // Tool input delta
+                                else if delta.get("type") == Some(&json!("input_json_delta")) {
+                                    if let Some((_, _, input_json)) = &mut current_tool_use {
+                                        if let Some(partial) =
+                                            delta.get("partial_json").and_then(|p| p.as_str())
+                                        {
+                                            input_json.push_str(partial);
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                        "content_block_stop" => {
+                            // Finalize tool use if we have one
+                            if let Some((id, name, input_json)) = current_tool_use.take() {
+                                tool_calls.push(ToolCall {
+                                    id: Some(id),
+                                    kind: "function".to_string(),
+                                    function: FunctionCall {
+                                        name,
+                                        arguments: input_json,
+                                    },
+                                });
+                            }
+                        }
+                        _ => {}
+                    }
+                }
+            }
+        }
+
+        Ok(CompletionResponse {
+            content: if accumulated_text.is_empty() {
+                None
+            } else {
+                Some(accumulated_text)
+            },
+            tool_calls: if tool_calls.is_empty() {
+                None
+            } else {
+                Some(tool_calls)
+            },
+        })
+    }
+}

src-tauri/src/llm/mod.rs

@@ -1,3 +1,4 @@
+pub mod anthropic;
 pub mod ollama;
 pub mod prompts;
 pub mod types;