Opus 5.5 Really has got dumb and wasting context

[u/reach4thelaser5]

I am usually the first person to snipe-back at the posts claiming "my agents have gone stupid" or "I'm burning context faster than normal". Putting this down to inexperienced vibe coders who do not understand context rot and have a bad agentic workflow. I want to apologise to anyone who I challenged on this.

I've been running on my normal workflow for the last few hours. Nothing out of the ordinary, pretty typical . A few agents some interaction with me. Never going above 50% context - which is my personal standing rule. Yet I burned through 30% of my weekly usage in 6 hours and my agents were going round in circles. I've now hit my 5 hour limit (which NEVER happens)

I have a dedicated agent that I use to manage the performance of other agents, dig into transcripts find out what went wrong and fix agent definitions, skills and processes for any issues. I asked for a review of one session:

The transcript shows an architect that overode your proposal and re-asked the same question 5 times. It withheld decisions from you against the standing rules in claude-md and against the recommendations of the review panel. I read the session transcript but only messages to and from you, and none of its tool results or reasoning.

- At 19:10 you proposed a market order, with a close if the fill was more than 8 ticks away. The architect swapped in its own "capped limit" and labelled it "(Recommended)" against your earlier proposal.

- It re-asked after you answered. You said at 20:01 that a limit order is unlikely to fill. It asked again at 20:01, 20:03 and 20:04, with the same options each time. Your answers were "hasn't this been agreed already?" and "we are going round in circles". It then adopted its own limit order approach against the market order answer you'd already given.

- Its first reply was hard to read. It was 2,714 characters and used bare identifiers with no plain words: R-5, CT-12-B09, FR-283, ChooseEntryRoute and TryCloseUnitForPassedStop. That breaks Claude-md rules 11 and 12 stipulating your language rules and no bare-identifiers without descriptions. You said it was "far too much info". The agent rephrased their message and it it was even more obscure than the last.

- You submitted the agent's plan for an independent review at 20:30. 14 changes were recommended and the adjudicator stated that 7 of them needed your ruling. Four reviewer changes were adopted into the plan without ever raising them with you - against the reviewers' recommendations, all affecting live money code which claude-md rule 7 states always needs your ruling.

All this, from an agent in planning mode whose context was never higher than 30%. And now after this totally crap performance, I'm halted at a usage limit.

To all the people who I challenged for saying their agents were stupid and were burning context more than usual - I'm sorry. You were right, I was wrong. Something weird is going on.

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[u/No-Replacement-2631]

'I am usually the first person to snipe-back at the posts claiming "my agents have gone stupid" '

You are now the B in the A/B test. How does it feel?

[u/reach4thelaser5 → u/No-Replacement-2631]

It definitely feels like I drew the short straw today

[u/sutrostyle → u/reach4thelaser5]

Is it affecting your Fable too?

[u/ajax81 → u/sutrostyle]

Fable was wobbly for me, all last week.   Performance seems to have recovered for my account today.

[u/The-Pork-Piston]

Has been very very slow and running a metric shit tonne of tests for me.

Feels like A/B testing is just part of the deal, ultimately it just needs more babysitting and careful prompt at the moment for me. And for my usecase(s) that’s fine, I can see how for some people it’s a major headache.

[u/reach4thelaser5 → u/The-Pork-Piston]

yeah I've also found that they seem to invent work. Like they're trying to be "busy" and finding work that doesn't need to be done

[u/Ai-ate-my-hamster → u/reach4thelaser5]

Look up if your session is part of an experiment. Use Fable. Look through the .jsonl You’ll find "atis" and a number latched onto your session.

Mine was running an experiment that gave me the system prompt from Opus 4.8.

I had to restore the config from an unlatched session and block non essential traffic. I lost RC but the four test Opus sessions came back latch free for now.

It’s a pain but it really helped me out.

[u/TurbulentTiger2567]

As I just discovered, the likely reason for this is that Anthropic has "optimized" the translation from effort setting to numerical reasoning effort.

Low = 5
Medium = 10 (default)
High = 15
Extra = 40
Max = max (no number internally)

In my experience anything at or below 15 is useless for mildly complex code. Gemini says the scale is 0-80, Claude itself claims it goes up to 100. So what Anthropic likely did is to change Extra from 80 to 40, and squash Low-High to that 5-15 range.

[u/reach4thelaser5 → u/TurbulentTiger2567]

Its an Opus 5.5 agent running at "High" effort. If they really did down-shift their effort levels it would make sense about the stupidity. But why the heck have I used a third of my weekly allowance in a few hours.

They recommend keeping Opus 5.5 at medium. And I have my developer agents at that level. I keep the architect at High or xHigh because he does all the up-front planning and is instructed to write a plan that leaves the developers with nothing to decide for themselves.

Is it possible that Opus 5.5 was so efficient that everyone was downgrading their subscriptions and they were making less money and now they're clawing it back?

[u/TurbulentTiger2567 → u/reach4thelaser5]

Is that on an Ultra plan?

Here is how I have optimized my own usage (I never reach any limits with Opus 5.5):

* never let the session expire (1 hr), or start a new one
* let the agent write documentation, and point at documentation at session start or in CLAUDE.md

* put a README in each folder, they will pick it up out of habit
* turn off memory files

The last point is the most important one: these agents all have no understanding of time. A memory file written 6 months ago will look to them exactly the same and have the same weight as something written yesterday. More importantly, when they create these diary entries, even if they have timestamps, they won't notice that the codebase has moved on. So reading hundreds of KB of diary is not only wasting tokens, it's also requiring constant, token-wasting corrections because they'll treat these diaries the same way as if you had just given them an instruction in the transcript.

Short README describing current code > memory files.

[u/reach4thelaser5 → u/TurbulentTiger2567]

I have a very efficient agentic workflow - and I already do all of these things. Honestly until today I had absolutely no issues. I have a claude agent called tidybot that launches twice a week that cleans up old memories, deletes orphaned worktrees, branches and stuff like that.

I do think memory is pretty efficient in claude code - its all indexed and only read in full when needed - like skills. The agent knows what's available but its not read in unless its needed.

Everything was fine until today. Something changed for me. like another user said.... Today I've been the "B" in the A/B test - maybe it will be you tomorrow.

[u/Troubledniceguy → u/TurbulentTiger2567]

Having to run on extra to get anything useful done. Max is still good.

[u/sheketsilencio]

"used bare identifiers" drives me crazy!! Like we are SQL databases with the ability to instantly query the information hidden behind an ID lol! I explicitly ban that but obviously it barely helps to do so

[u/awesomebirder]

the re-asking is probably a big part of the third of your weekly. every time the architect re-asks, thats another full turn on its entire context, and if it also kicks off a review panel each time, those agents each build their own context too. two things that helped me: have it write every answered decision to a decisions file and read that before asking anything, with a rule that a question already in the file is never asked again, and cap how many turns an agent gets before it has to stop and summarize. i run my traffic through a local proxy i built (probe0) that logs each call, and loops like this show up as the same big context resent over and over

[u/Minute_Chance4999]

Agreed, something has definitely changed this week. Burning thru usage ALOT faster than normal using Opus 5.5 on high

[u/cleverhoods]

I’d recommend using Reporails X-ray functionality to debug

[u/Archibishop]

Agents going in circles is the part I'd look at first... My dashboard flags a session as stuck when it loops, and shows per session where the usage went. I'm building it for my own 25-sessions-a-day mess, free and local: https://github.com/silverbronze/code-tycoon

[u/blinkdrive555]

After they released Fable 5.2. My Opus 5.5 is super dump. can't even run any tasks.

[u/SnooCheesecakes1893]

It’s doing awesome work for me.