More proactive about uncertainty
Answers more often flag what’s uncertain; missed defects in self-written code drop sharply—suited as a collaboration primary.
Anthropic · Claude Opus 4.8 · May 2026
Claude Opus 4.8 — more reliable coding and tool collaboration
- Million-token context
- Extra-long single replies
- Usually high depth
- Stronger alignment and honesty
What is Claude Opus 4.8?
Claude Opus 4.8 is Anthropic’s Opus released in May 2026, with noticeable upgrades versus Claude Opus 4.7 on collaboration judgment, agent reliability, and honesty. It usually works at high depth; harder jobs can go deeper. New long-horizon coding and knowledge work more often pick Claude Opus 5; if workflows are already validated on 4.8—or you need a steady Opus fallback—you can keep using it. On iMini Agent, pick Claude Opus 4.8 to use it.
- Vendor
- Anthropic
- Released
- May 2026
- Context
- 1M tokens
- Max output
- 128K tokens
- Deep thinking
- Usually high depth · tunable
- Best as
- Primary for validated Opus workflows
What’s new versus Claude Opus 4.7
Honesty, agent judgment, and computer use—what to check before moving from 4.7 to 4.8.
More reliable agent judgment
Fewer extra steps in tool calls and multi-step jobs—cleaner paths to the same intelligence outcomes.
Stronger computer and browser agents
Clear lifts on official computer-use evals such as Online-Mind2Web—suited to end-to-end web and desktop flows.
Better alignment audits
Deception and assisting-misuse rates drop sharply versus 4.7, approaching Mythos Preview safety levels at the time.
Official evaluations and safety audits
Results Anthropic published with Claude Opus 4.8, compared with Claude Opus 4.7, GPT-5.5, and Gemini 3.1 Pro—covering software engineering, multidisciplinary reasoning, computer use, and behavioral alignment.
Three common workflows
Claude Opus 4.8 still fits validated Opus-tier work; new flagship loads can compare Opus 5.
Coding collaboration & review
For feature work, defect hunting, and evidence-based PR review. Suited to teams whose prompts and evals already bind to 4.8.
Computer use & browser flows
For multi-step jobs that operate a web or desktop environment. Write completion criteria and abort conditions clearly.
Domain professional agents
For legal, finance, and other flows that need steady judgment. New ceiling long-horizon jobs can re-evaluate Opus 5 or Fable 5.
How to choose vs Claude Opus 5 and Claude Sonnet 5
All three are Claude workhorses. The differences are generation ceiling, high-frequency cost, and whether your workflow is already validated.
| Dimension | Claude Opus 4.8 | Claude Opus 5 | Claude Sonnet 5 |
|---|---|---|---|
| Context | 1M tokens | 1M tokens | 1M tokens |
| Reasoning | Usually high depth, tunable | Deep thinking built in, tunable | Tunable depth tiers |
| Coding / agents | Opus coding & collaboration | Current long-horizon coding flagship primary | Scaled agents & everyday coding |
| Long tool runs | Steady Opus-tier collaboration | Stronger goal holding and completion | Better as a high-frequency primary |
| Speed posture | Quality and experience in balance | Completion quality first | Throughput first |
| Prefer when | Workflows already validated on 4.8 | New long-horizon coding and knowledge work | New high-frequency agent primary |
Using Claude Opus 4.8 on iMini
Free quota, model naming, key specs, and how it differs from Opus 5.
Use Claude Opus 4.8 free on iMini Agent
Million-token context, usually high depth, suited to validated Opus workflows.
Open Claude Opus 4.8No Anthropic API key required.