Claude Opus 4.8

Claude Opus 4.8 is an Opus-tier model from Anthropic aimed at agentic coding, legal and financial document work, and complex multi-step reasoning in enterprise workflows.

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input · usd / 1m tok

$5.00

output · usd / 1m tok

$25.00

context window

1mtokens

modalities · in → out

pricing

base api ratesusd per 1m tokens

input: $5.00
output: $25.00
cache read: $0.50
cache write · default ttl: $6.25
cache write · 1h ttl: $10.00

providers

Different companies host Claude Opus 4.8. Impossibl routes your request intelligently and handles failover automatically when a provider is down.

Azure AI Foundry
Anthropic

specifications

takes text and image in, gives text outanthropic/claude-opus-4-8

creatorAnthropic
model typeText generation
context window1,000,000 tokens
maximum outputnot published
input
takes text and image in, gives text out
outputtext
tool callingnot verified
releasedmay 28, 2026
endpoint/v1/chat/completions

unknown means the public catalog does not establish that fact. a model's documented capabilities can differ from what a particular api supports. see the model documentation for integration details.

try it · your prompt, this model, live

# responses API
import os
from openai import OpenAI

client = OpenAI(
    api_key=os.environ["IMPOSSIBL_API_KEY"],
    base_url="https://api.impossibl.com/v1",
)

resp = client.responses.create(
    model="anthropic/claude-opus-4-8",
    input="▌",
)
print(resp.output_text)

edit the prompt, then run

# responses API
import os
from openai import OpenAI

client = OpenAI(
    api_key=os.environ["IMPOSSIBL_API_KEY"],
    base_url="https://api.impossibl.com/v1",
)

resp = client.responses.create(
    model="anthropic/claude-opus-4-8",
    input="▌",
)
print(resp.output_text)

edit the prompt, then run

benchmarks

intelligence index

41.8#26 of 113 models on the gateway

coding index74.3#15 of 66
agentic index41.9#17 of 54
omniscience28.8#7 of 90
gpqa92.0%#15 of 82
humanity’s last exam48.7%#8 of 93

Tau294.4%
GPQA92.0%
AA-LCR77.7%
IFBench62.2%
Terminal-Bench Hard58.3%
SciCode54.4%
Humanity’s Last Exam48.7%
AutomationBench Partial45.6%
AnalystAgent45.0%
Tau Banking34.2%
GDP.pdf All-pass22.8%
CritPt20.9%
Multilingual LCR19.4%

Intelligence Index41.79
Omniscience Index28.75
GDPval Elo1452.80
legal index (API)47.9
coding index (API)74.3
agentic index (API)41.9
economics index (API)53.8
engineering index (API)43.5
intelligence index (API)41.8
strategy and ops index (API)44.1
finance and accounting index (API)46
healthcare and medical index (API)41.3

view source ↗all source data and breakdowns (json) ↗

each configuration is listed separately; these evaluations describe the tested model configuration, and performance and costs can differ on impossibl. unmeasured scores are omitted and api values keep their source units. last checked 2026-10-22.

compare Claude Opus 4.8 with other models

frontier labs and open weights, best-ranked firstusd / 1m tok · in / out

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frequently asked questions

What is Claude Opus 4.8?

Claude Opus 4.8 is an Opus-tier model from Anthropic aimed at agentic coding, legal and financial document work, and complex multi-step reasoning in enterprise workflows. Over Opus 4.7 it is far more willing to flag flaws and uncertainties, catches its own mistakes during agentic runs, and uses tokens more efficiently.

How much does Claude Opus 4.8 cost?

Claude Opus 4.8 costs $5.00 per million input tokens and $25.00 per million output tokens through the Impossibl API. Cache reads cost $0.50 per million tokens; cache writes cost $6.25 per million tokens; cache writes with one-hour retention cost $10.00 per million tokens. All rates are in USD.

view the pricing table ↑

What is the context length of Claude Opus 4.8?

Claude Opus 4.8 has a 1,000,000-token context window through the Impossibl API.

What inputs and outputs does Claude Opus 4.8 support?

Claude Opus 4.8 accepts text and image as input. Claude Opus 4.8 returns text.

How do I use Claude Opus 4.8 through an API?

Claude Opus 4.8 is available through the Impossibl API. Use anthropic/claude-opus-4-8 as the model identifier with /v1/chat/completions. The quickstart explains how to create an API key and send your first request.

follow the api quickstart →

When was Claude Opus 4.8 released?

Anthropic released Claude Opus 4.8 on May 28, 2026.

Creator release announcement ↗

this page describes Claude Opus 4.8 as listed by the impossibl public api. prices and availability come from that catalog, refreshed here every five minutes. this is an impossibl offering, not a comparison of independent hosting-provider quotes. model descriptions and release dates, where available, use the creator sources linked under the answers above.

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