Porting a Sume agent loop to Haiku 5.5: drop temperature, top_p, top_k

Remove temperature, top_p and top_k from every request that targets claude-haiku-5-5. The Haiku 5.5 overview tells you to omit them and points to a migration section listing the values that return a 400. If your tool-calling loop for Sume was written for an older model with temperature=0 set for repeatability, the first request after the model swap can fail for that reason alone.

Port checklist

These are the items on the model page that change a loop. None of them concerns Sume's API.

What repeatability means now

You no longer get determinism from temperature, so make the Sume side safe to repeat instead. Every paid call carries an idempotency_key derived from your own order id; replaying the same turn then returns the original job and does not create a second one. See the tools and gates page.

Budget for the tokenizer: a tool list that was a given size on Haiku 4.5 is about 30% larger in tokens on 5.5, which matters near the 100,000-token price step.

A one-hour port

Search your codebase for the three parameter names and for any wrapper that injects them. Remove them for the Haiku 5.5 branch only; leave them in place for older models while both are running. Change the model id to claude-haiku-5-5, run one tool call against Sume's read-only tools such as balance_get and check the response before enabling any paid tool.

Then check effort. Adaptive thinking is on by default at medium; a polling agent does not need more, and a lower setting is cheaper. Test that your loop's stop conditions still work.

• Read-only smoke test first.
• Branch by model id.
• Re-measure tokens after the swap.