feat(routing): add type_safe_classifier backed by TypeSafe's Jev

CHANGELOG.md

@@ -8,6 +8,14 @@ adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ### Added
 
+- **TypeSafe classifier routing** — new `type_safe_classifier` route type
+  routes through TypeSafe's Jev "System One Model" instead of a
+  chat-completion judge. `switchyard-libsy` stays I/O-free: the classifier
+  depends only on a new `TypeSafeProvider` port, and a new
+  `switchyard-typesafe-client` crate supplies the runner-owned HTTP
+  implementation, injected once per deployment via a `[type_safe_client]`
+  table. Fails open on a low-confidence, unresolved, or out-of-range verdict,
+  or a provider error. (#723)
 - **`timeout_ms` on `[llm_clients.<name>]`** — one deadline covers all attempts,
   retry delays, and the complete response, including stream reads. Unset leaves
   the wait unbounded; `0` is rejected. A timeout returns `504` without trying another

Cargo.toml

@@ -15,6 +15,7 @@ members = [
     "crates/switchyard-skill-distillation",
     "crates/switchyard-soak",
     "crates/switchyard-translation",
+    "crates/switchyard-typesafe-client",
 ]
 
 [workspace.package]
@@ -49,6 +50,7 @@ switchyard-protocol = { path = "crates/protocol", version = "0.3.0" }
 switchyard-runner = { path = "crates/switchyard-runner", version = "0.3.0" }
 switchyard-server = { path = "crates/switchyard-server", version = "0.3.0" }
 switchyard-translation = { path = "crates/switchyard-translation", version = "0.3.0" }
+switchyard-typesafe-client = { path = "crates/switchyard-typesafe-client", version = "0.3.0" }
 strum_macros = "0.28"
 thiserror = "2"
 tokio = { version = "1", features = ["full"] }

README.md

@@ -247,6 +247,7 @@ Most use an LLM as a judge. All of them pick between an **efficient** model and
 | Algorithm | How it decides | Route `type` | Benchmark |
 |---|---|---|---|
 | **[Capability](docs/routing_algorithms/llm_classifier_routing.md)** | The first request is judged by an LLM. | `llm_classifier` | 71.2% at $79.32 |
+| **[TypeSafe Classifier](docs/routing_algorithms/type_safe_classifier_routing.md)** | Every request is judged by TypeSafe's Jev, a non-generative classifier — no chat-completion judge call. | `type_safe_classifier` | not yet benchmarked |
 | **[Stage](docs/routing_algorithms/stage_router_routing.md)** | Tool responses are judged by pattern matching or an LLM. | `stage_router` | 72.7% at $68.19 |
 | **[Capability + Stage](docs/routing_algorithms/composite_routing.md)** | Combines the two above. | `composite` | not yet benchmarked |
 | **[Escalation](docs/routing_algorithms/escalation_router_routing.md)** | Starts efficient. Responses are judged by an LLM for issues, then escalated. | `llm_classifier` + `mode = "escalation"` | 75.7% at $85.00 |

crates/libsy/src/algorithms.rs

@@ -16,6 +16,7 @@ pub mod passthrough;
 pub mod rand;
 pub mod stage;
 pub mod subagent;
+pub mod type_safe_class;
 
 pub mod util;
 

crates/libsy/src/algorithms/llm_class.rs

@@ -92,7 +92,7 @@ impl TaskClassifierVerdict {
 /// Selects by reference and clones only what survives — a coding-agent
 /// conversation carries every tool result, so cloning it whole to keep a window
 /// would copy the transcript on each judged turn.
-fn trim_messages(messages: &[Message], recent_turn_window: usize) -> Vec<Message> {
+pub(crate) fn trim_messages(messages: &[Message], recent_turn_window: usize) -> Vec<Message> {
     let is_instruction = |message: &Message| matches!(message.role, Role::System | Role::Developer);
     let mut kept: Vec<&Message> = messages.iter().filter(|m| is_instruction(m)).collect();
     let Some(task) = messages.iter().position(|m| m.role == Role::User) else {
@@ -149,7 +149,7 @@ fn window_start(tail: &[&Message], recent_turn_window: usize) -> usize {
 }
 
 /// Keeps the opening task and the latest user follow-up when they differ.
-fn task_messages(messages: &[Message]) -> Vec<Message> {
+pub(crate) fn task_messages(messages: &[Message]) -> Vec<Message> {
     let mut user_messages = messages.iter().filter(|message| message.role == Role::User);
     let Some(opening_task) = user_messages.next() else {
         return Vec::new();
@@ -498,7 +498,7 @@ impl JudgePolicy for CustomPolicyRuntime {
 }
 
 /// Builds the affinity router a trigger calls for, if any.
-fn affinity_router(
+pub(crate) fn affinity_router(
     trigger: ClassifyTrigger,
     message_hash_fallback: bool,
 ) -> Option<Arc<AffinityRouter>> {