$ cat wiki/models/claude-sonnet-5.md
Claude Sonnet 5
modelupdated 2026-07-21created 2026-07-02
Spec
| Attribute | Value |
|---|---|
| Developer | Anthropic |
| Tier | Sonnet (mid-tier) |
| Released | 2026-06-30 |
| Announced | 2026-06-30 |
| Context window | 1M tokens |
| Pricing | $2/M input · $10/M output (promo, through 2026-08-31); $3/M input · $15/M output (standard, from 2026-09-01) |
| License | unknown |
| Availability | Claude.ai (all tiers), Claude Code, API |
| Default model | Yes — Claude Free, Claude Pro, Claude Code |
Release Date
June 30, 2026 — released the same day as Fable 5/Mythos 5 export-control restoration and Claude Science launch.
Benchmarks
| Benchmark | Sonnet 5 | Sonnet 4.6 | Opus 4.8 |
|---|---|---|---|
| SWE-bench Pro | 63.2% | 58.1% | 69.2% |
| Terminal-Bench 2.1 | 80.4% | — | 74.6% |
| BrowseComp (single agent) | 84.7% | — | — |
| BrowseComp (multi-agent, 10M token budget) | 86.6% | — | — |
| GDPval-AA v2 (knowledge work) | 1,618 | — | 1,615 |
| OSWorld-Verified (computer use) | 81.2% | — | — |
| Notable: On three of five agentic benchmarks (Terminal-Bench 2.1, BrowseComp, GDPval-AA v2), Sonnet 5 matches or surpasses Opus 4.8 — at approximately one-fifth to one-thirteenth the price. |
(sources), (DataCamp), (MarkTechPost)
Use Cases
- Drop-in upgrade for agentic coding workflows running on Sonnet 4.6 — same pricing tier, significantly higher capability
- Long-horizon browser + terminal automation (BrowseComp 84.7% / Terminal-Bench 80.4%)
- Knowledge-intensive multi-step workflows at low cost (GDPval-AA: 1,618 > Opus 4.8: 1,615)
- Default model for general Claude users on Free/Pro plans
Adaptive Thinking & Effort Levels
Sonnet 5 introduces adaptive thinking with five effort tiers: low, medium, high, max, x-high. Higher effort levels allocate larger thinking budgets per response for greater accuracy at higher token cost. This mirrors the pattern introduced in Opus 4.8 (Dynamic Workflows) and extends it to the mid-tier model.
Safety Improvements
Per the Anthropic system card:
- Lower hallucination and sycophancy rates vs. Sonnet 4.6
- Stronger refusal of malicious requests
- Increased resistance to prompt injection in agentic contexts
- No explicit safety gating (unlike Fable 5's <5% Opus 4.8 gate)
Compared To
| Model | SWE-bench Pro | Input price/Mtok | Context |
|---|---|---|---|
| Claude Fable 5 | 80.3% | $10 | 1M |
| Claude Sonnet 5 | 63.2% | $2 (promo) | 1M |
| Claude Opus 4.8 | 69.2% | $15 | 1M |
| Claude Sonnet 4.6 | 58.1% | $3 | — |
| Sonnet 5 at $2/$10 vs. Opus 4.8 at $15/$75 is the intended efficiency play: close to Opus-class on most agentic tasks at ~13× lower input cost. |
Related
- Claude Fable 5 — Mythos-class public frontier; Sonnet 5 is the efficient mid-tier below it
- Claude Opus 4.8 — prior Opus-tier frontier; Sonnet 5 surpasses it on several agentic benchmarks
- Anthropic
- Agents (LLM Agents) — Sonnet 5 designed for agentic use cases