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AnthropicClaude 4 familyLegacyReasoning modelReleased 24 Nov 2025

Claude Opus 4.5

Legacy Opus; migrate to claude-opus-5-5.

Model idclaude-opus-4-5-20251101

Price$5 in, $25 out per 1M tokens

Checked29 September 2026

Knows up to May 2025

2,019events after its cutoff

89 historic, 467 major. 531 days of news.

It launched on 24 November 2025, already missing 45 of them. Coverage before 2026 is thin (80 entries for 2025), so this count is a floor.

Five things it has never heard of

Its cutoff, May 2025, is before this chart starts: every mark here is news it has never seen.

How to call it

7 ways to use Claude Opus 4.5, with the model id each provider expects.

Providers, model ids, endpoints and docs for Claude Opus 4.5
ProviderModel idEndpointDocs
Anthropic API (Claude API) claude-opus-4-5-20251101Alias claude-opus-4-5 https://api.anthropic.com/v1/messages platform.claude.com
AWS Bedrock (InvokeModel) anthropic.claude-opus-4-5-20251101-v1:0 platform.claude.com
Google Cloud Vertex AI claude-opus-4-5@20251101 platform.claude.com
Microsoft Foundry (Azure) claude-opus-4-5 platform.claude.com
Claude Platform on AWS claude-opus-4-5 platform.claude.com
OpenRouter anthropic/claude-opus-4.5 openrouter.ai
Web app claude.ai

Pricing

Prices for Claude Opus 4.5
Input$5 per 1M tokens
Output$25 per 1M tokens
Cache read$0.50 per 1M tokens

As published: “per 1M tokens (USD); Batch API 50% off”.

Source: platform.claude.com, checked 29 September 2026.

Specs

Input
Text, images and PDF
Output
Text
Context window
200,000 tokens
Max output
64,000 tokens
Open weights
No
Licence
Proprietary
Training cutoff
May 2025
Released
24 November 2025
Status
Legacy
Type
Reasoning model

What stands out

What its maker marketed at launch, and what people found later, each with its source.

  • Beat all human candidates on Anthropic’s engineering exam

    First

    Scored higher than any human candidate on Anthropic’s take-home engineering exam within the 2-hour limit.

    Source: anthropic.com

  • Effort parameter

    First

    First model with the effort parameter. At medium effort it matched Sonnet 4.5’s best score with 76% fewer output tokens.

    Source: anthropic.com

  • Prompt-injection robustness

    Anthropic claimed it was harder to trick with prompt injection than any other frontier model at the time.

    Source: anthropic.com

  • Opus price cut

    Opus-class pricing dropped to $5/$25 per MTok, from $15/$75.

    Source: anthropic.com

Four assistants, one scale

Claude Opus 4.5 is added as a fifth row. Each row runs from what the model knows (graphite) through the months between its cutoff and its launch (hatched) to today (pink).

  1. GPT-6 Astra 271 at launch, 1,863 today
  2. Claude Opus 5.5 372 at launch, 1,795 today
  3. Gemini 4 Hydrogen 1,863 at launch, 1,889 today
  4. Grok 4.7 387 at launch, 1,829 today
  5. Claude Opus 4.5 45 at launch, 2,019 today
Show as a table
ModelCutoffReleasedMissing at launchMissing today
GPT-6 AstraApril 20263 September 20262711,863
Claude Opus 5.5June 202622 September 20263721,795
Gemini 4 HydrogenMarch 202612 November 20261,8631,889
Grok 4.7May 202621 September 20263871,829
Claude Opus 4.5May 202524 November 2025452,019

Notes

Snapshot claude-opus-4-5-20251101 (alias claude-opus-4-5). Extended thinking (budget_tokens); effort low/medium/high. Training data cutoff Aug 2025. Retirement not sooner than 2026-11-24.

curl https://api.anthropic.com/v1/messages \
 -H "x-api-key: $ANTHROPIC_API_KEY" -H "anthropic-version: 2023-06-01" -H "content-type: application/json" \
 -d '{"model":"claude-opus-4-5","max_tokens":16000,"messages":[{"role":"user","content":"Hello"}]}'

Sources: