Family map
The family names are a historical compression system. Haiku usually marks lower-latency and lower-cost work. Sonnet is the central general-purpose tier. Opus marks the higher-capability tier. The 2026 docs also place Fable above Opus for broadly released highest-capability work and Mythos in a trusted-access context that shares the underlying Fable model with more permissive safeguards.
| Family or era | Historical role | Examples | Primary source |
|---|---|---|---|
| Claude and Instant | Original public naming before the Haiku/Sonnet/Opus ladder. | Claude, Claude Instant | Introducing Claude |
| Claude 2 | Public beta, API availability, large-context writing and analysis. | Claude 2, Claude 2.1 | Claude 2.1 |
| Claude 3 | Persistent family ladder begins. | Haiku, Sonnet, Opus | Claude 3 family |
| Claude 4.x | Agentic coding, tool use, computer use, context growth, pricing resets. | Sonnet 4.6, Opus 4.8, Haiku 4.5 | Models overview |
| Claude 5 era | Fable/Mythos naming for highest-capability releases, Opus 5 as the successor Opus tier, and Sonnet 5 for cost-effective agentic work. | Fable 5, Fable 5.1, Mythos 5.1, Opus 5, Sonnet 5 | Fable/Mythos 5.1 |
Dated snapshot: September 19, 2026
As of the September 19, 2026 verification pass, the models overview lists Claude Fable 5.1, Claude Opus 5, Claude Sonnet 5, and Claude Haiku 4.5 in the latest-models comparison, with Fable 5, Opus 4.8/4.7/4.6/4.5, and Sonnet 4.6/4.5 still listed as legacy. Mythos 5.1 shares the Fable 5.1 model under trusted access.
| Model | API ID | Launched | Context | Price in/out per MTok |
|---|---|---|---|---|
| Claude Fable 5.1 | claude-fable-5-1 | 2026-09-01 | 1M | $10 / $50 |
| Claude Opus 5 | claude-opus-5 | 2026-07-24 | 1M | $5 / $25 |
| Claude Sonnet 5 | claude-sonnet-5 | 2026-06-30 | 1M | $2 / $10 |
| Claude Haiku 4.5 | claude-haiku-4-5 | 2025-10-15 | 200K | $1 / $5 |
This is a dated snapshot of the record, not a recommendation. Which of these to pick for a given workload is answered at Claude Central, and cost-per-token analysis at Claude Reports. Snapshots matter here because older launch posts stay online after the lineup moves: Claude 3.5 Sonnet remains historically important, but the deprecation ledger records that both 2024 Sonnet 3.5 model IDs were retired on October 28, 2025.
Model IDs are archive evidence
Launch names are human-readable, but model IDs are what production systems use. The deprecation page tracks IDs such as claude-3-7-sonnet-20250219, claude-opus-4-1-20250805, and claude-haiku-4-5-20251001. That makes the deprecation page the best place to answer questions about broken legacy calls.
Use model IDs when writing migration notes. Use model names when writing historical narrative. Use both when you need an answer that a developer can act on.
Neighbor topics
This page does not teach prompt engineering, context management, or Claude Code practice. For those, use Claude Context, Claude Memories, and Claude Ships Code. Claude Archive stays on dates, IDs, pricing, retirement, and official source trail.
Questions this page answers
What are the main Claude model family names?
The main recurring family names are Haiku, Sonnet, and Opus. 2026 sources add Fable for the highest-capability generally available releases and trusted-access Mythos, which shares the Fable model with more permissive safeguards.
Which Claude models have a 1M-token context window?
The September 2026 models overview lists 1M-token context windows for Claude Fable 5.1, Claude Opus 5, and Claude Sonnet 5. Claude Haiku 4.5 remains at 200K.
What are the Claude Fable 5.1 and Claude Opus 5 model IDs?
The platform docs list claude-fable-5-1 for Fable 5.1 and claude-opus-5 for Opus 5.
Where should I check current model IDs?
Use the official Claude Platform models overview for current IDs and the model deprecations page for retired or deprecated IDs. For a recommendation about which model to use, see claudecentral.com/models.