Feature: Embedded Anthropic→OpenAI proxy with multi-backend failover

crates/proxy-server/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "proxy-server"
+version = "0.1.0"
+edition = "2024"
+description = "Embedded Anthropic Messages → OpenAI Chat Completions proxy with multi-backend failover"
+
+[dependencies]
+serde = { workspace = true }
+serde_json = { workspace = true }
+ureq = { workspace = true }
+thiserror = { workspace = true }

crates/proxy-server/src/config.rs

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+use serde::Deserialize;
+use std::collections::HashMap;
+
+/// Provider configuration.
+#[derive(Debug, Clone, Deserialize)]
+#[serde(untagged)]
+pub enum ProviderConfig {
+    Simple(SimpleProvider),
+    OpenRouter(OpenRouterConfig),
+}
+
+#[derive(Debug, Clone, Deserialize)]
+pub struct SimpleProvider {
+    pub base_url: String,
+    #[serde(default)]
+    pub api_key: Option<String>,
+    pub model: Option<String>,
+    pub kind: Option<String>,
+}
+
+#[derive(Debug, Clone, Deserialize)]
+pub struct OpenRouterConfig {
+    pub base_url: Option<String>,
+    pub api_key: String,
+    pub model: String,
+}
+
+#[derive(Debug, Clone, Default, Deserialize)]
+pub struct ProxyConfig {
+    /// Listen address (default 127.0.0.1)
+    #[serde(default = "default_bind")]
+    pub bind: String,
+    /// Listen port (default 3000)
+    #[serde(default = "default_port")]
+    pub port: u16,
+    /// Ordered list of upstream providers for failover.
+    #[serde(default)]
+    pub providers: Vec<NamedProvider>,
+    /// Model remapping: client model → upstream model.
+    #[serde(default)]
+    pub model_map: HashMap<String, String>,
+    /// Reasoning model override (used when request has thinking enabled).
+    pub reasoning_model: Option<String>,
+    /// Completion model override (used for standard requests).
+    pub completion_model: Option<String>,
+    /// Terms to strip from system prompts before forwarding.
+    #[serde(default)]
+    pub system_prompt_ignore_terms: Vec<String>,
+}
+
+#[derive(Debug, Clone, Deserialize)]
+pub struct NamedProvider {
+    pub name: String,
+    #[serde(flatten)]
+    pub config: ProviderConfig,
+}
+
+fn default_bind() -> String {
+    "127.0.0.1".into()
+}
+
+fn default_port() -> u16 {
+    3000
+}
+
+impl ProxyConfig {
+    pub fn from_toml(input: &str) -> Result<Self, toml::de::Error> {
+        toml::from_str(input)
+    }
+
+    pub fn default_with_openrouter(api_key: &str, model: &str) -> Self {
+        Self {
+            providers: vec![NamedProvider {
+                name: "openrouter".into(),
+                config: ProviderConfig::OpenRouter(OpenRouterConfig {
+                    base_url: None,
+                    api_key: api_key.into(),
+                    model: model.into(),
+                }),
+            }],
+            ..Self::default()
+        }
+    }
+}

crates/proxy-server/src/lib.rs

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+mod backend;
+mod config;
+mod failover;
+mod server;
+mod translate;
+
+pub use config::ProxyConfig;
+pub use server::ProxyServer;
+pub use translate::TranslationError;