feat(libsy): add system prompt judge route

README.md

@@ -261,6 +261,7 @@ Most use an LLM as a judge. All of them pick between an **efficient** model and
 | **[Advisor Gate](docs/routing_algorithms/advisor_gate_routing.md)** | One model serves every turn; a stronger advisor approves its plans and "done" claims, or sends it back. | `advisor` | lifts a weak executor 43.8% → 54.7% |
 | **[Sub-Agent-Aware](docs/routing_algorithms/subagent_routing.md)** | Delegated sub-agent traffic routes separately from the parent agent. | `subagents` on `passthrough` or `stage_router` | not yet benchmarked |
 | **[Custom](docs/routing_algorithms/llm_classifier_routing.md#custom-multi-target-routing)** | The first request is judged by an LLM against criteria you define, routing among 2+ of your own models. | `llm_classifier` + `target_selector` policy | not yet benchmarked |
+| **[System Prompt Judge](docs/routing_algorithms/system_prompt_judge_routing.md)** | A judge chooses one hidden system prompt from a text DB before a passthrough call. | `system_prompt_judge` | not yet benchmarked |
 | **[Random](docs/routing_algorithms/random_routing.md)** | Each request is routed at random, uniform or weighted. | `random` | baseline mechanism |
 
 Benchmarks are Terminal-Bench 2.1 against a $98.06 Opus 4.8 baseline at 76.0%.

crates/libsy/src/algorithms.rs

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