[clinic · EX-14] Beat the reranker

[akash-coded]

Exercise clinic. One long-running thread per exercise. Ask here rather than opening a
new thread — the answers accumulate where the next person will look for them.

Exercise: EX-14 — Beat the reranker · difficulty 🔴

What this exercise asks

Read the exercise first; this thread is for when you are stuck, not instead of it.

Three ways people get stuck on this one

1. Adding features the first stage already used. A reranker over the same signals is an expensive identity function — the finding in #4.

2. Tuning weights before checking the feature set. The grid search in #4 lost, and that is what promoted the diagnosis from weights to features.

3. Reranking a depth so shallow that there is nothing left to reorder.

How to ask here

Post the numbers you got, the config that produced them, and what you already tried.
A question with a measurement in it gets answered in one round trip; a question without one
takes three.

If you have finished it, post the write-up in Show and Tell with the
[solution · EX-14] prefix rather than here — this thread stays for people who are stuck.