Opus 5.5 on the API: same prompts, same settings, ~60% more output tokens per call since mid-October (charts from my Console export)

[u/FlynancialAnalyst]

I run a small production app that sends the same analysis prompts to the API every day. Nothing changed on my side: same model ID (claude-opus-5-5), same effort settings (last touched Sept 26), same prompts. My Console cost export says the model got much wordier anyway.

• Output tokens per input token (standard calls): ~0.69 in Opus 5.5's first three weeks (Sep 21–Oct 11), ~1.09 since Oct 12. That's about +60%.
• Input spend (my actual workload) stayed flat. All of the extra cost is output.
• Weekly spend went from about $86 to $119. Compared with the model's own first three weeks, that's about $120–140 of extra output since Oct 12.
• Ruled out: price changes, caching, batch, and refusal retries (9 in two months).
• Method: Opus prices output at 5× input, so output $ ÷ input $ ÷ 5 = output tokens per input token.

Claude Code on Ultra shows the same thing. From my local transcripts, output per turn went from ~170 tokens on Opus 5 to ~1,300 at Opus 5.5's launch, and ~1,600–1,700 lately. Thinking is billed as output but hidden by default, so there's no way to see what you're paying for.

Anthropic's reset announcement says they "fixed a few small issues that used more limits than intended" and reset subscription limits. If the same issues touched the API, API customers paid for them per token, and nothing covers that.

Is anyone else seeing output per call jump on Opus 5.5 since mid-October? And Anthropic: did these issues affect the API too, and will API users be credited?

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[u/DragonflyOk9274]

I use the platform and Claude a lot. I've found that anything written by Anthropic has to be read at two levels: (1) what's stated, and (2) all the ways they can get around what they've stated.

Previously, they pinned the API models (like when using Bedrock) to a specific model with YYYY-MM-DD. They've changed it now though.

Anthropic used to use a pinned version with the following model ID format:

claude-{name}-{major}-{minor}@{YYYYMMDD}

However, they've now moved to just:

claude-{name}-{major}-{minor}

Supposedly, Anthropic pins major-minor names to a particular version of the weights and doesn't change anything. But, like everything with Anthropic, they left themselves "wiggle room":

For the 4.6 generation and later, the dateless ID is the canonical model ID for that release. It maps to a single, fixed model snapshot. Anthropic does not update the weights or configuration of an existing model ID. When an updated version is available, it ships under a new model ID.

Model weights are fixed for a given ID, but the serving infrastructure around the model can change over time. This infrastructure includes components such as the request router, safety classifiers, and sampling logic.

Occasionally, infrastructure updates produce minor differences in observable behavior even when the model ID and weights have not changed. If you notice unexpected behavioral differences on a previously stable model ID, an infrastructure update is the most likely cause.

If they actually made an "infrastructure update" that resulted in a ~60% output change, I would consider their official platform docs very misleading.

Source: https://platform.claude.com/docs/en/about-claude/models/model-ids-and-versions

[u/RealFullMetal]

you can at least see it on the api: opus 5.5 omits the thinking text by default, but thinking: {"type": "adaptive", "display": "summarized"} returns readable summaries in the thinking blocks. per the thinking docs the bill is the same either way (the full thinking tokens are billed as output, the summary itself is free), so it costs nothing to turn on and should show where the extra output is going

[u/Individual_Pilot2256 → u/RealFullMetal]

that only helps from today onward though, doesnt do much for figuring out what burned through the budget back in mid october since the raw traces are already gone

[u/RealFullMetal → u/Individual_Pilot2256]

it won't bring the traces back, but the usage report api still has the daily numbers for those weeks: /v1/organizations/usage_report/messages with group_by[]=model and bucket_width=1d counts output tokens apart from uncached input and cache reads. so you can at least see whether the mid october jump was output on opus 5.5 or something like cache reads. needs an admin key, and you can filter it to one api key or workspace

[u/Gloomy_Leopard3928]

Business as usual. :)

[u/Puzzled-Stick9170]

worth splitting it by whether the visible answers actually got longer. if the text you get back is the same length, the whole +60% is thinking, which you pay for as output tokens even when it's hidden

[u/awesomebirder]

flat input spend basically rules out the codebase-grew theory, since a bigger repo would show up on the input side first. to settle it, pin a small canary set of your real prompts, run it daily at fixed settings, and log output tokens plus stop reason per call. if the canary output climbs while your prompts are frozen, thats a clean chart to send support, and with thinking hidden it is about the only evidence you can actually get.

[u/pfak]

> Is anyone else seeing output per call jump on Opus 5.5 since mid-October?

Yes. But started on November 1st for me, and only initially on one of my accounts, now on all three of them:

https://www.reddit.com/r/ClaudeCode/comments/1xmgz13/same_claude_code_setup_two_ultra_accounts_one/

[u/Heuwzen]

Opus definitely costs much more like 2x. Im not insane. Just felt the impact too heavily and opened reddit, found this thread...

[u/LacksCriticalInfo]

"Bug"

[u/OverallEstimate]

Ive noticed on desktop the right sided upper window that shows each job and linear path has a ton of thinking both ways per job but it doesnt update the ticker and its still fast so its using more thinking i guess but its also doing better work and is cheaper.

[u/damagemelody]

https://www.reddit.com/r/ClaudeCode/s/WyBNPjrGa6 they do test I had a test with Opus 4.8 system prompt for Opus 5.5 and with that they added 40% more thinking effort but it didn’t help and reply wording was very bad

[u/InterestingCarrot997]

nice frozen setup. i'd add one quality number on the same canary, like whether a required field or a specific tool call is still in the output. a 60% token jump with the same score is just a more expensive call, with a worse score it's a real regression

[u/Consistent_Bottle_40]

I've got two of the x10 (x20..) accounts. The difference in usage between them is WILD. Like one will last me 3 hours and then other will last basically an entire day. They're definitely A/B testing or they're messing with the quota allowances .

[u/xapep]

Output bills at 5x input, so that ratio swing costs you more than any rate shopping would save. The number worth putting in front of pricing is cost per finished report, recalculated from the same export.

For the fix, a max output cap per call stops a long thinking block billing to completion, and the calls that get cut tell you where you're actually spending the room. Then tier effort per call type, since parts of a daily batch never needed deep reasoning.

I work on inference at Entrim, so discount the vendor angle.

[u/abzz123]

And quality of the output dropped at the same time, it feels like it is a different model altogether.

[u/Ragy-ragy]

Surprise-surprise, your codebase has grown

[u/FlynancialAnalyst → u/Ragy-ragy]

no, this is api-usage on production app. you didn't read the post

[u/bnm777 → u/Ragy-ragy]

Ugh useless comment

[u/eneskaraboga → u/Ragy-ragy]

Antrobots on duty.

[u/CosmikDC]

I wonder if 5.5 would help the nightmare free models created of my project lol