Rebuild Fable 5's deep-research fan-out on your own keys (OrcaRouter)

The Stack

Tested Against

Prerequisites

• An OrcaRouter account (hosted DSL, BYOK)
• Provider API keys to actually run the panel

Steps

1. 1

   Author the fan-out routing rule and lint it

   Pick the panel, pick the arbiter (synthesize to fuse, best_of_n to return the single best verbatim). Write routing.yaml with a deep_research rule that fans out to a parallel panel and resolves it with an arbiter. CI runs the DSL lint and checks the panel, a valid arbiter strategy, version 1, and a default; the panel and judge only run with your keys, so that step is fenced.

   cat > routing.yaml <<'YAML'
   version: 1
   rules:
     - id: deep_research
       when: task_class == "rag" || reasoning_cue_count > 2
       use:
         parallel:
           - { model: "anthropic/claude-opus-4.8" }
           - { model: "openai/gpt-4o" }
           - { model: "google/gemini-3.1-pro-preview" }
         arbiter:
           strategy: synthesize
           model: "anthropic/claude-opus-4.8"
           template: best_answer_v1
         max_latency_ms: 120000
   default:
     delegate: balanced
   YAML
   ruby -ryaml -e '
   c = YAML.safe_load(File.read("routing.yaml"))
   abort "BAD: version must be 1" unless c["version"] == 1
   abort "BAD: no default" unless c["default"]
   rule = (c["rules"] || []).find { |r| r["id"] == "deep_research" }
   abort "BAD: no deep_research rule" unless rule
   use = rule["use"] || {}
   panel = use["parallel"]
   abort "BAD: deep_research has no parallel panel" unless panel.is_a?(Array) && panel.length >= 2
   allowed = ["best_of_n", "synthesize", "majority", "first", "tests_pass"]
   arb = use["arbiter"] || {}
   abort "BAD: arbiter strategy not allowed" unless allowed.include?(arb["strategy"])
   puts "config OK: deep_research fans out to a " + panel.length.to_s + "-model panel with arbiter strategy " + arb["strategy"] + ", version 1, default present"
   '

2. 2

   Run it on your keys (the model step, not checked by CI)

   Point your OpenAI-compatible client at OrcaRouter; the deep_research rule fans out and the arbiter fuses or picks. Every leg bills at provider cost, so use it where being wrong is expensive. The deliberation is fenced.