Published: 2026-09-24
Analysis & perspective

Opus 5.5 at every effort level on one /goal build: $3.91 at low, $50 at max — and xhigh won

Chapters / key moments (click to jump — plays here on the page)

The clearest effort-level data we've seen for Opus 5.5. One long autonomous task (turn 105 GB of event recordings into an explorable 3D conference) was run through /goal at every level, with every run measured. Opus 5.5 defaults to medium in Claude Code (model config docs).

Source video

"I Had Opus 5.5 Build me the Same App at Every Effort Level" by Nate Herk — Watch on YouTube →

The numbers

Effort	Runtime	API-equivalent cost	Tokens	Checks	Questions asked
low	16 m 43 s	$3.91	191K	22	0
medium	1 h 13 m	$12.44	419K	23	0
high	1 h 07 m	$16.31	~559K	22	1
xhigh ("extra")	~1 h 30 m	$25.92	~732K	34	0
max	2 h 28 m	$50.38	1.18M (auto-compacted)	51	0
ultracode	1 h 35 m	$18.69	as reported	42	0

Numbers as read out in the video. He ran on a subscription and computed API-equivalent cost. Some token figures are garbled in the auto-captions and are shown approximately. No run used subagents.

What the quality looked like

low: working but off-brand, still images instead of video, glitching NPCs.
medium: used his brand guidelines, played real session video, NPCs reacted. "For a lot of my knowledge work, medium works just fine."
high: best loading screen, working VIP flow and afterparty, closed captions on stage.
xhigh: his winner. You could talk to NPCs, sit in any session, and it had the best physics. It cost about half of max in time and money.
max: slowest and most expensive, with worse walking and more bugs. "Way too much for not enough good."

Ultracode didn't behave like ultracode

Per the Claude Code workflows docs, /effort ultracode makes Claude plan a workflow for every substantive task in the session. In his runs it never started one. It behaved like xhigh with more checks. He doesn't know whether that's a harness bug or Opus 5.5 declining workflows, so if you rely on ultracode, check that workflows actually start. See our dynamic workflows FAQ.

How to use this

/effort xhigh        # low | medium | high | xhigh | max | ultracode | auto
/effort status
/goal <condition>     # keep working across turns until the condition is met

Start at the default (medium) and step up only when the task needs deep reasoning over a lot of material, as Anthropic's own prompting guide suggests.
For long autonomous /goal runs, xhigh was the sweet spot here. Max roughly doubled cost and time for a worse result.
Per the docs, max and ultracode are session-only. Everything else persists.

Background: what each effort level does. (Includes a sponsor segment.)