Models
Anthropic
Claude Opus 5.5 (High) Pareto Frontier for Agent

@arenaX · Sep 28, 2026

Claude Opus 5.5 (High) Pareto Frontier for Agent

@arena's line chart drew 27.3K views on X: 0.6x its median post and #656 of 1,162 AI chart posts we hold by views. Read Oct 12, 2026.

Claude Opus 5.5 (High) Pareto Frontier for Agent Arena

XData Line chart Claude Opus 5 All Anthropic modelsClaude Opus 5.5 (High)Claude Fable 5.1 (Max)GPT-5.1 Sol (Max)Claude Sonnet 5 (High)Hy4 previewDeepseek V4.1 Flash (Max)GPT-5.6 Luna (xHigh)Mimo V2.5 Pro

@arena: Claude Opus 5.5 (High) Pareto Frontier for Agent — Published by @arena on X, Sep 28, 2026. Source: x.com

50/ 100

ViralChart score

Small but loved

Fewer views than the median post but a higher engagement rate: a smaller crowd that acted on it.

#626 of 1,162 AI chart posts we hold · #147 of 239 @arena posts. Score = views 40%, likes 30%, engagement rate 15%, save rate 15%, each as a percentile of every AI chart post we hold.

Our read

Small but loved: views below the AI chart median, engagement at or above it, score #626 of 1,162.

Its 27.3K views ranked #5 of 5 posts from @arena that day, below the launch-day direction.

Its 0.96% engagement rate hit the 70th percentile, above the 0.73% median for all AI chart posts.

Its 27.3K views were 0.59x the company median of 46.2K, ranking #160 of 239 @arena posts.

0.12views per follower

27.3K views from an account with 234.1K followers.

5posts from @arena that day

Part of a run of 5 posts on Sep 28, 2026. This one was #5 of 5 by views that day.

0.4xthe median line chart post

Across 68 line chart posts we hold, the median gets 73.7K views.

top 30%engagement rate

0.96% of viewers liked, reposted, quoted or replied. The median post gets 0.73%.

Public X numbers from our read on Oct 12, 2026. Peers: 1,162 AI chart posts we hold and 239 from @arena.

Where it sits

Reach against resonance

Each dot is a post. Right is more views, up is a higher engagement rate. The lines are the medians, so the four corners are the four kinds of post.

Among 1,162 AI chart posts we hold

Score #626 of 1,162

Views	27.3K	#656	bottom 44%
Likes	241	#613	bottom 47%
Engagement rate	0.96%	#347	top 30%
Save rate	0.081%	#555	top 48%

Among 239 @arena posts

Score #147 of 239

Views	27.3K	#160	bottom 33%
Likes	241	#148	bottom 38%
Engagement rate	0.96%	#56	top 23%
Save rate	0.081%	#115	top 48%

Growth

One read so far

Views27.3K

Age at our read14 days

Views per day of life1.9Kviews divided by days since it was posted

Dots are our reads. The dotted line from the day it was posted to our first read is a gap, not data.

@arena's posts over time

Every post from this account we hold, by date and views. This one is marked; the line is the running median of the last 10.

News · Sep 28, 2026

@arena's Claude Opus 5.5 Pareto chart draws 27.3K views

A line chart with 9 models, posted September 28, 2026, alongside 4 other posts that day.

What happened

@arena posted a line chart on Claude Opus 5.5 (High) Pareto Frontier for Agent Arena on September 28, 2026. It was 1 of 5 posts that day, with 4 others including Agent Arena Leaderboard at 123K views.

The numbers

The post got 27.3K views, ranking #656 of 1,162 AI chart posts. Its engagement rate was 0.96%, ranking #347 of 1,162, and its save rate was 0.081%.

The lesson

A 9-model line chart with 1 chart in the post got 0.96% engagement, above the 0.73% median. Readers engaged with the comparison despite below-median views.

What it means

At 0.59x the company median views, this post underperformed @arena's typical reach. Yet its engagement rate beat the account's 0.68% median, showing a niche audience.

Written by ViralChart from public numbers read on Oct 12, 2026. Every number is checked against our data before it is shown.

Updates: what @arena posted next

Data and API

10 points read off this chart

Estimated from the image 39%

Group	Value	Read
Claude Opus 5.5 (High)	12.15 %	estimated
Claude Fable 5.1 (Max)	12.5 %	estimated
GPT 5 Sol (Max)	7.5 %	estimated
Claude Sonnet 5 (High)	5 %	estimated
Hy4 preview	4.5 %	estimated
Deepseek V4.1 Flash (Max)	3.5 %	estimated
GPT 5.6 Luna (xHigh)	-5 %	estimated
Hy3	-6 %	estimated
Mimo V2.5 Pro	-8 %	estimated
Anthropic-Proprietary	12.15 %	estimated

Max plan · API

GET https://viral-chart.com/api/posts/91ba993b70b6.json
GET https://viral-chart.com/api/charts/91ba993b70b6.json
GET https://viral-chart.com/api/charts/91ba993b70b6.skill.md

Make one like this Open the post JSON Chart data JSON Skill file API docs

Static files in this prototype. The post JSON holds the public numbers, ranks, score, quadrant, our reads and, when checked, our copy.

API · Max

Use this chart via API

On the Max plan you can pull this chart's numbers with the provenance of each one, as JSON or CSV, with its redraw spec, or call it from an agent over MCP. Chart id 91ba993b70b6.

Approximate values. Our two readings of this chart agreed only in part (confidence 0.39 of 1), so check the original before you quote a number. The API marks it lowConfidence, and ?min_confidence=0.5 leaves it out.

See the Max plan API docs

	Path	Returns	Plan
GET	`/api/v1/charts/91ba993b70b6`	Title, publisher, date, form, point count; with a Max key, the data link	Open
GET	`/api/v1/charts/91ba993b70b6/data`	Every point with its provenance and confidence, plus the redraw spec. Add ?format=csv for CSV	Max
GET	`/api/v1/charts/91ba993b70b6/render?view=1`	The draw-only view this page uses	Open
POST	`/mcp`	Tool get_chart_data with this id, for Claude, Cursor and other agents	Max

curlMax

curl -s https://viral-chart.com/api/v1/charts/91ba993b70b6/data \
  -H "Authorization: Bearer $VIRALCHART_KEY"

Claude CodeMax

claude mcp add --transport http viralchart https://viral-chart.com/mcp \
  --header "Authorization: Bearer $VIRALCHART_KEY"

60 requests a minute per key; over that you get 429 with Retry-After. Up to 5 keys per account, made on your account page and shown once. Without Max, the data route answers 402 with a link to the plans. The numbers describe a chart its publisher owns, and every file carries a license note.

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