diff --git a/crates/owlen-core/src/lib.rs b/crates/owlen-core/src/lib.rs
index 2b0fb6b..831a8e4 100644
--- a/crates/owlen-core/src/lib.rs
+++ b/crates/owlen-core/src/lib.rs
@@ -18,6 +18,7 @@ pub mod mcp;
 pub mod mode;
 pub mod model;
 pub mod oauth;
+pub mod provider;
 pub mod providers;
 pub mod router;
 pub mod sandbox;
@@ -50,6 +51,7 @@ pub use mcp::{
 };
 pub use mode::*;
 pub use model::*;
+pub use provider::*;
 pub use providers::*;
 pub use router::*;
 pub use sandbox::*;
diff --git a/crates/owlen-core/src/provider/mod.rs b/crates/owlen-core/src/provider/mod.rs
new file mode 100644
index 0000000..7424a5b
--- /dev/null
+++ b/crates/owlen-core/src/provider/mod.rs
@@ -0,0 +1,34 @@
+//! Unified provider abstraction layer.
+//!
+//! This module defines the async [`ModelProvider`] trait that all model
+//! backends implement, together with a small suite of shared data structures
+//! used for model discovery and streaming generation.
+
+mod types;
+
+use std::pin::Pin;
+
+use async_trait::async_trait;
+use futures::Stream;
+
+pub use self::types::*;
+
+use crate::Result;
+
+/// Convenience alias for the stream type yielded by [`ModelProvider::generate_stream`].
+pub type GenerateStream = Pin<Box<dyn Stream<Item = Result<GenerateChunk>> + Send + 'static>>;
+
+#[async_trait]
+pub trait ModelProvider: Send + Sync {
+    /// Returns descriptive metadata about the provider.
+    fn metadata(&self) -> &ProviderMetadata;
+
+    /// Check the current health state for the provider.
+    async fn health_check(&self) -> Result<ProviderStatus>;
+
+    /// List all models available through the provider.
+    async fn list_models(&self) -> Result<Vec<ModelInfo>>;
+
+    /// Acquire a streaming response for a generation request.
+    async fn generate_stream(&self, request: GenerateRequest) -> Result<GenerateStream>;
+}
diff --git a/crates/owlen-core/src/provider/types.rs b/crates/owlen-core/src/provider/types.rs
new file mode 100644
index 0000000..a6f64ac
--- /dev/null
+++ b/crates/owlen-core/src/provider/types.rs
@@ -0,0 +1,124 @@
+//! Shared types used by the unified provider abstraction layer.
+
+use std::collections::HashMap;
+
+use serde::{Deserialize, Serialize};
+use serde_json::Value;
+
+/// Categorises providers so the UI can distinguish between local and hosted
+/// backends.
+#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
+pub enum ProviderType {
+    Local,
+    Cloud,
+}
+
+/// Represents the current availability state for a provider.
+#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
+pub enum ProviderStatus {
+    Available,
+    Unavailable,
+    RequiresSetup,
+}
+
+/// Describes core metadata for a provider implementation.
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+pub struct ProviderMetadata {
+    pub id: String,
+    pub name: String,
+    pub provider_type: ProviderType,
+    pub requires_auth: bool,
+    #[serde(default)]
+    pub metadata: HashMap<String, Value>,
+}
+
+impl ProviderMetadata {
+    /// Construct a new metadata instance for a provider.
+    pub fn new(
+        id: impl Into<String>,
+        name: impl Into<String>,
+        provider_type: ProviderType,
+        requires_auth: bool,
+    ) -> Self {
+        Self {
+            id: id.into(),
+            name: name.into(),
+            provider_type,
+            requires_auth,
+            metadata: HashMap::new(),
+        }
+    }
+}
+
+/// Information about a model that can be displayed to users.
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+pub struct ModelInfo {
+    pub name: String,
+    #[serde(default)]
+    pub size_bytes: Option<u64>,
+    #[serde(default)]
+    pub capabilities: Vec<String>,
+    #[serde(default)]
+    pub description: Option<String>,
+    pub provider: ProviderMetadata,
+    #[serde(default)]
+    pub metadata: HashMap<String, Value>,
+}
+
+/// Unified request for streaming text generation across providers.
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+pub struct GenerateRequest {
+    pub model: String,
+    #[serde(default)]
+    pub prompt: Option<String>,
+    #[serde(default)]
+    pub context: Vec<String>,
+    #[serde(default)]
+    pub parameters: HashMap<String, Value>,
+    #[serde(default)]
+    pub metadata: HashMap<String, Value>,
+}
+
+impl GenerateRequest {
+    /// Helper for building a request from the minimum required fields.
+    pub fn new(model: impl Into<String>) -> Self {
+        Self {
+            model: model.into(),
+            prompt: None,
+            context: Vec::new(),
+            parameters: HashMap::new(),
+            metadata: HashMap::new(),
+        }
+    }
+}
+
+/// Streamed chunk of generation output from a model.
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+pub struct GenerateChunk {
+    #[serde(default)]
+    pub text: Option<String>,
+    #[serde(default)]
+    pub is_final: bool,
+    #[serde(default)]
+    pub metadata: HashMap<String, Value>,
+}
+
+impl GenerateChunk {
+    /// Construct a new chunk with the provided text payload.
+    pub fn from_text(text: impl Into<String>) -> Self {
+        Self {
+            text: Some(text.into()),
+            is_final: false,
+            metadata: HashMap::new(),
+        }
+    }
+
+    /// Mark the chunk as the terminal item in a stream.
+    pub fn final_chunk() -> Self {
+        Self {
+            text: None,
+            is_final: true,
+            metadata: HashMap::new(),
+        }
+    }
+}