Development

One release takes math, search, economic value and software engineering

development2026-04-26

Claim

OpenAI released GPT-5.5 and GPT-5.5 Pro, posting 39.6% on FrontierMath Tier 4, 90.1% on BrowseComp, 84.9% on GDPval and 82.7% on Terminal-Bench 2.0, while leaping to 25.0% on a multi-stage scientific analysis benchmark from 19.0% a version earlier.

Reported metric: 84.9% GDPval

Reporting date: 2026-04-26 (not necessarily the event date)

Sources

Attribution and reporting linked by this record; links do not imply independent verification.

Welcome to April 26, 2026 (theinnermostloop.substack.com)

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Reported in

Welcome to April 26, 2026

Actor

OpenAI

Evidence for

Supersedes

The measured autonomy horizon reaches a full working week

Referenced by

Cite or correct this record

Citation formatCitation text

One release takes math, search, economic value and software engineering
Innermost Loop KB — secondary record
Reporting date: 2026-04-26
KB permalink: https://nicholsn.github.io/innermost-loop-kb/developments/2026-04-26-gpt-55-sweeps-four-domains
Claim: OpenAI released GPT-5.5 and GPT-5.5 Pro, posting 39.6% on FrontierMath Tier 4, 90.1% on BrowseComp, 84.9% on GDPval and 82.7% on Terminal-Bench 2.0, while leaping to 25.0% on a multi-stage scientific analysis benchmark from 19.0% a version earlier.
Attributed sources:
- Welcome to April 26, 2026 — https://theinnermostloop.substack.com/p/welcome-to-april-26-2026
This citation does not imply independent verification of linked-source claims.

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