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Anthropic
Humanity's Last Exam: Accuracy vs Cost

AnthropicX · Sep 1, 2026 · official

Humanity's Last Exam: Accuracy vs Cost

Anthropic's line chart drew 483K views on X: 1.1x its median post and #153 of 1,162 AI chart posts we hold by views. Read Oct 13, 2026.

Accuracy vs cost for Fable models on Humanity's Last Exam

XData Line chart Claude Fable 5 All Anthropic modelsFable 5.1 (with tools)Fable 5.1 (no tools)Fable 5 (with tools)Fable 5 (no tools)

Anthropic: Humanity's Last Exam: Accuracy vs Cost — Published by Anthropic on X, Sep 1, 2026. Source: x.com

70/ 100

ViralChart score

Wide but thin

More views than the median post but a lower engagement rate: many saw it, few acted. Common for big accounts.

#220 of 1,162 AI chart posts we hold · #27 of 56 Anthropic 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

The post sits in the Wide but thin quadrant, at #220 of 1,162 AI chart posts.

Its score of 70 sits at #220 of 1,162 AI chart posts, above the median.

The post carries 4 charts, and every chart in the post shares the post's numbers.

Its save rate of 0.039% lands at the 20th percentile among AI chart posts, below the 0.076% median.

4charts in this one post

The numbers belong to the post, so every chart in it shares them and it is ranked once.

6.6xthe median line chart post

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

0.25views per follower

483K views from an account with 1.9M followers.

bottom 20%save rate

0.039% of viewers bookmarked it to come back to. The median post gets 0.076%.

Public X numbers from our read on Oct 13, 2026. Peers: 1,162 AI chart posts we hold and 56 from Anthropic.

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 #220 of 1,162

Views	483K	#153	top 13%
Likes	2.5K	#120	top 10%
Engagement rate	0.55%	#771	bottom 34%
Save rate	0.039%	#930	bottom 20%

Among 56 Anthropic posts

Score #27 of 56

Views	483K	#27	top 47%
Likes	2.5K	#24	top 42%
Engagement rate	0.55%	#29	bottom 49%
Save rate	0.039%	#41	bottom 28%

Growth

Our reads cover 28 hours

Views483K

Age at our read42 days

Views per day of life11.5Kviews divided by days since it was posted

Gained between our reads+55views over 28 hours, about 48 a day now

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

Anthropic'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 1, 2026

Anthropic posts Fable accuracy vs cost on Humanity's Last Exam

A 4-chart Anthropic post on September 1, 2026 drew 483K views and a 0.55% engagement rate, with saves below the AI chart median.

What happened

Anthropic published a line chart on September 1, 2026 covering accuracy vs cost for Fable models on Humanity's Last Exam. The post carried 4 charts, and the account made 3 posts that day, including Claude Fable 5.1 Benchmark Comparison and Indexed cost of Fable usage.

The numbers

The post reached 483K views, #153 of 1,162 AI chart posts, against a median of 39.9K. Its score of 70 ranks #220 of 1,162 AI chart posts and #27 of 56 Anthropic posts.

The lesson

A save rate of 0.039% against the 0.076% median among AI chart posts shows this 4-chart post was kept less than the typical chart. The chart shows pass rate from 50.5% to 60% across printed points.

What it means

At #27 of 56 Anthropic posts, this chart sits below the account's own top posts, and its 0.039% save rate trails the 0.076% median among AI chart posts.

Written by ViralChart from public numbers read on Oct 13, 2026. Every number is checked against our data before it is shown.

Updates: what Anthropic posted next

Data and API

36 points read off this chart

Estimated from the image 50%

Series	Group	Value	Read
Fable 5.1 (with tools)	0.2	50.5 %	printed
Fable 5.1 (with tools)	0.3	53.5 %	printed
Fable 5.1 (no tools)	0.4	55.5 %	printed
Fable 5 (with tools)	0.5	55.5 %	printed
Fable 5.1 (with tools)	0.6	60 %	printed
Fable 5 (no tools)	0.6	56.5 %	printed
Fable 5.1 (no tools)	0.7	59.5 %	printed
Fable 5 (with tools)	0.8	61 %	printed
Fable 5 (no tools)	1.0	57 %	printed
Fable 5.1 (with tools)	1.2	62 %	printed
Fable 5.1 (no tools)	1.5	61.5 %	printed
Fable 5 (with tools)	2.0	62.5 %	printed

Showing 12 of 36. All points, the redraw and the maker

Max plan · API

GET https://viral-chart.com/api/posts/7249dfc13b69.json
GET https://viral-chart.com/api/charts/7249dfc13b69.json
GET https://viral-chart.com/api/charts/7249dfc13b69.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 7249dfc13b69.

See the Max plan API docs

	Path	Returns	Plan
GET	`/api/v1/charts/7249dfc13b69`	Title, publisher, date, form, point count; with a Max key, the data link	Open
GET	`/api/v1/charts/7249dfc13b69/data`	Every point with its provenance and confidence, plus the redraw spec. Add ?format=csv for CSV	Max
GET	`/api/v1/charts/7249dfc13b69/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/7249dfc13b69/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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