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ANTHROPIC · MODEL RELEASE TRACKER

Claude Opus 4.8

Claude Opus 4.8 is a named Anthropic model/version referenced in research and media reports. Excerpts describe its evidence-acquisition behavior on a SAFE benchmark, its role in security-research exploits, and that it is the predecessor to Opus 5.

CURRENT SNAPSHOT0/5 DIMENSIONS WITH DATA

The dimensions that change the decision.

PRICING

Not established from the available sources.

CONTEXT WINDOW

Not established from the available sources.

MODALITIES

Not established from the available sources.

BENCHMARKS

Not established from the available sources.

AVAILABILITY

Not established from the available sources.

RELEASE TIMELINE

Published, source-backed release events only.

6 SOURCES · IMPORTANCE 8.0

Anthropic releases Claude Opus 5 — lower-cost model claiming near‑frontier performance

Anthropic announced Claude Opus 5, a new model positioned as a cost‑efficient successor to Opus 4.8 and the new default on Claude Max (and the strongest on Claude Pro). Anthropic says Opus 5 matches or exceeds prior models on many coding, knowledge‑work and scientific benchmarks (Frontier‑Bench, GDPval‑AA, CursorBench, ARC‑AGI, Zapier AutomationBench, OSWorld) at lower cost per task while remaining behind Mythos 5 on security and biology frontier tasks; the company also reports improved alignment and safety in pre‑deployment audits and links a System Card for more details.

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VERIFIABLE FACTS

Every value stays attached to a source and date.

SAFETY · Evidence-acquisition behavior on SAFE benchmarkINDEPENDENTLY SUPPORTED

On the SAFE benchmark, Claude Opus 4.8 “inspects nearly by default”: it tends to acquire safety-relevant evidence before acting. The paper reports distinct evidence-acquisition policies across models (GPT-5.5, o3, Claude Opus 4.8, Claude Sonnet 4.6), and that inspection increases strongly with severity and decreases with retrieval cost.

RELEASE · Predecessor to Opus 5DEVELOPER CLAIM

Anthropic describes Opus 5 as providing greatly improved performance for the same cost as its predecessor, Opus 4.8, indicating that Opus 4.8 is the immediate prior version to Opus 5.

WHAT CHANGED

Stored passport versions, without reconstructed history.

Passport created2 facts