| name | effort-router |
| description | Pick and re-evaluate the output_config.effort level for a Claude Fable 5 workload. Use when designing a pipeline that mixes routine and hard tasks, when a call feels slow or expensive for what it's doing, or when porting an Opus 4.7/4.8 harness that defaulted to xhigh. |
Effort Router
Effort is the dial that trades intelligence for latency and cost on Fable 5. Two mistakes dominate: carrying over an old model's default effort unexamined, and picking one effort for an entire pipeline instead of per task class.
Defaults, not habits
high is the API default and the right starting point for most analysis, writing, and agentic/coding work.medium (or low when latency is visible to a user) for routine transforms: classification, short edits, formatting.xhigh only for the tasks that actually need it: large migrations, one-way-door changes, multi-day autonomous runs.max almost never — reserve it for problems where xhigh measurably fell short, not as a default upgrade.
If you're migrating a harness built for Opus 4.7 or 4.8, don't keep xhigh "because that's what coding needs" — that guidance was for the older model. Re-test at high first; Fable 5 at high frequently matches or beats an older model at xhigh.
Route by task class
A triage step at low/medium that escalates only the cases that need it to high/xhigh beats any single fixed setting across a mixed workload — see job_packet/packet.py in this repo for a working example: prep and execute run cheap, plan_or_audit spends the premium effort only where judgment is dense.
Self-check
Before shipping a pipeline's effort settings, ask: if I doubled every effort level, would output quality visibly improve? If not, you're overpaying somewhere.
