Scegliere un modello Claude
Principiante
Anthropic offre una famiglia di modelli con diversi punti di equilibrio tra capacità/costo/velocità. Scegliere bene significa soprattutto adattare il modello al compito — e non pagare troppo per capacità di cui non hai bisogno.
- Leggere la scala Haiku → Sonnet → Opus come un compromesso tra capacità, costo e velocità
- Partire dal default giusto invece di tirare a indovinare, per poi salire o scendere in modo deliberato
- Combinare più livelli in un unico sistema — la leva di costo più grande che quasi nessuno usa
- Cercare l'ID esatto del modello nel modo giusto, così gli aggiornamenti restano una modifica di una riga
I modelli attuali
Last verified: 2026-11-02 · Official models & pricing
| Model | API model ID | Tier | Best for |
|---|---|---|---|
| Claude Fable 5.1 | claude-fable-5-1 | Mythos-classflagship (above Opus) | Released September 1, 2026. For demanding reasoning and long-horizon agentic work, or when Opus 5.5 at higher effort still falls short on your evals — Anthropic's models overview recommends starting with Opus 5.5 for most workloads and reaching for Fable 5.1 only when it falls short. Same list price as Fable 5 with cache reads at a quarter of the cost. Three breaking changes vs Fable 5: forced tool_choice (any/tool) returns 400, thinking blocks are readable only by Fable 5.1 or newer, and editing earlier turns invalidates thinking blocks. Refuses in-band (HTTP 200, stop_reason: refusal); fallback targets are Opus 5 and Opus 4.8. 30-day retention (not ZDR-eligible unless expressly authorized by Anthropic); not on Priority Tier. (Supersedes Claude Fable 5, now a legacy model.) |
| Claude Mythos 5.1 | claude-mythos-5-1 | Mythos-classverification required | Same capabilities, specs and pricing as Fable 5.1, available only to organizations verified through Anthropic's verification programs. Since October 6, 2026 that is an application, not an invitation: Project Glasswing was restructured into the Cyber Verification Program's three tiers — Defense Access (organizations, and individuals on paid plans), Red Team Access (organizations only) and Specialized Access (organizations only, reviewed with the US government, where Glasswing members landed) — each granting Opus 5.5, Sonnet 5.5 and Mythos 5.1. Apply at portal.anthropic.com/programs; decisions typically within seven business days. Does not run the conversation-binding check on thinking blocks. Customers without access should use Fable 5.1. |
| Claude Opus 5.5 | claude-opus-5-5 | Opusmost capable | Anthropic's recommended starting point for most workloads, released September 22, 2026: long-running agentic coding and knowledge work, 1M context, 128k output, June 2026 reliable knowledge cutoff. Beats the larger Fable 5.1 on every row of Anthropic's launch table at 40% of its list price. Default effort is 'medium' (shared only with Haiku 5.5 — every other model that supports effort defaults to 'high'), and at a given level it thinks more per turn than Opus 5 — re-run your effort sweep instead of carrying settings over. Four breaking changes vs Opus 5: thinking cannot be disabled at any effort level (400), forced tool_choice (any/tool) returns 400 including on token counting, thinking blocks are bound to both the model and the conversation prefix, and computer_20251124 is rejected on the Claude API and Google Cloud (still accepted on Bedrock). A fifth change returns 200: text between tool calls now arrives in progress-update thinking blocks, empty at the default display of 'omitted'. Refuses in-band (HTTP 200, stop_reason: refusal) with new 'bio' and 'reasoning_extraction' categories; server-side fallback does NOT retry 'reasoning_extraction'. Fast mode is Claude API only. Retirement no sooner than September 22, 2027. (Supersedes Claude Opus 5, now a legacy model.) |
| Claude Opus 5 | claude-opus-5 | Opusmost capable | Legacy since September 22, 2026 (superseded by Opus 5.5) but still available. Complex agentic coding and enterprise work, 1M context, 128k output. Two reasons to stay on it for now: it accepts thinking: {type: 'disabled'} at 'high' effort or below, and its thinking blocks are readable by more models than Opus 5.5's (only Fable 5.1 and Mythos 5.1 read Opus 5.5's). (Supersedes Claude Opus 4.8, now a legacy model.) |
| Claude Sonnet 5.5 | claude-sonnet-5-5 | Sonnetbalanced | The best combination of speed and intelligence, released September 28, 2026: well-scoped everyday tasks, bug fixes, multistep tool use and polished documents, 1M context, 128k output (300k on Batches with a beta header), June 2026 reliable knowledge cutoff. Exactly Sonnet 5's prices and the same tokenizer, yet Anthropic claims output 30%+ faster and up to 30% less per task — the saving is in the token and turn counts, not the rate card. Beats Opus 5.5 on Terminal-Bench 4.0 (70.6% vs 66.4%) and ties it on knowledge-work Elo, but trails it by ~8 points on FrontierCode 1.1. Default effort is 'high' and levels are recalibrated — re-run your sweep. Minimum cacheable prompt drops to 512 tokens (1,024 on Sonnet 5). Five breaking changes vs Sonnet 5: thinking: {type: 'disabled'} returns 400 (use 'between_tools', accepted only at 'high' effort or below and with no companion field), forced tool_choice (any/tool) returns 400 including on token counting, thinking blocks are bound to the model, the conversation prefix and the producing account, computer_20251124 is rejected on the Claude API and Google Cloud (still accepted on Bedrock), and Opus 4.8 / Opus 4.7 / Sonnet 5 are rejected as advisor-tool advisors. A sixth change returns 200: text between tool calls arrives in progress-update thinking blocks, empty at the default display of 'omitted'. Refuses in-band (HTTP 200, stop_reason: refusal) in five categories; server-side fallback retries only 'cyber' and 'frontier_llm', on Sonnet 5. temperature/top_p/top_k at non-default values return 400. Retirement no sooner than September 28, 2027. (Supersedes Claude Sonnet 5, now a legacy model.) |
| Claude Sonnet 5 | claude-sonnet-5 | Sonnetbalanced | Legacy since September 28, 2026 (superseded by Sonnet 5.5) but still available. The balanced pick when speed and cost matter more than Opus-level depth, 1M context. Two reasons to stay on it for now: it accepts thinking: {type: 'disabled'} at any effort level including 'xhigh' and 'max' (Sonnet 5.5's 'between_tools' tops out at 'high'), and it supports forced tool_choice, which Sonnet 5.5 does not. It is also the server-side fallback target for Sonnet 5.5's 'cyber' and 'frontier_llm' refusals. (Supersedes Claude Sonnet 4.6, now a legacy model.) |
| Claude Haiku 5.5 | claude-haiku-5-5 | Haikufastest & cheapest | The fastest model, released October 7, 2026: high-volume, latency-sensitive work — classification, extraction, routing, and cheap sub-agents. 1M context (up from Haiku 4.5's 200k), 128k output (up from 64k, 300k on Batches with a beta header), June 2026 reliable knowledge cutoff (up from Feb 2025), and the first Haiku with adaptive thinking and the effort parameter (default 'medium'). THE ONLY CURRENT MODEL PRICED BY PROMPT LENGTH: every other 4.6-and-later model bills the full 1M window at standard rates, but Haiku 5.5 has two rate cards split at 100,000 tokens, and crossing that line reprices the WHOLE request — input, output, cache writes, cache reads and batch — at 5x. It also moves to the newer tokenizer, so the same text counts ~30% more tokens than on Haiku 4.5: the real saving is ~87% below the cliff and ~35% above it, not the 90% on the rate card. Five breaking changes vs Haiku 4.5: budget_tokens thinking returns 400, non-default temperature/top_p/top_k return 400, assistant prefill returns 400 even with thinking off, computer_20250124 is rejected on the Claude API and Google Cloud, and sending thinking blocks back after editing earlier turns returns 400. Unusually permissive where the bigger 5.5 models are not — it accepts both thinking: {type: 'disabled'} (at 'high' effort or below) and forced tool_choice, which Opus 5.5 and Sonnet 5.5 both reject. Refuses in-band (HTTP 200, stop_reason: refusal) in four categories with NO server-side fallback. Priority Tier is not supported. Retirement no sooner than October 7, 2027. (Supersedes Claude Haiku 4.5, now a legacy model.) |
| Claude Haiku 4.5 | claude-haiku-4-5-20251001 | Haikufastest & cheapest | Legacy since October 7, 2026 (superseded by Haiku 5.5) but still available, and still the only model with a 200k context window (not 1M), a 64k output cap, and no support for the effort parameter; its reliable knowledge cutoff is Feb 2025. Three reasons to stay on it for now: it accepts assistant prefill and manual extended thinking (budget_tokens), both of which Haiku 5.5 rejects with a 400, and it supports Priority Tier, which Haiku 5.5 does not. It is also flat-rated — Haiku 5.5's cheaper price applies only to prompts up to 100,000 tokens. Watch its lifecycle closely: its earliest-possible retirement date of October 15, 2026 has now PASSED, so it can be deprecated at any time — yet as of November 2, 2026 the status table still lists it Active with no deprecation announced. It is the only current model past its floor (Opus 4.5 is next, on November 24, 2026) and it now has a direct successor. This is a signal to plan, not an outage: Anthropic commits to at least 60 days' notice once a deprecation is announced, so a migration started now has room. |
| Claude Fable 5 | claude-fable-5 | Mythos-classflagship (above Opus) | Legacy since September 1, 2026 (superseded by Fable 5.1) but still available. Multiday autonomous runs, first-shot on ambiguous specs, dense vision, sustained delegation to parallel subagents. GA June 9 2026. Refuses in-band (HTTP 200, stop_reason: refusal) — configure server-side or client-side fallback. Adaptive thinking only; raw thinking never returned. 30-day retention (NOT ZDR-eligible). Two reasons to stay on it for now: it supports forced tool_choice and Priority Tier (existing commitments only — new ones are no longer sold), which Fable 5.1 does not. |
| Claude Mythos 5 | claude-mythos-5 | Mythos-classverification required, legacy | Superseded by Mythos 5.1. Shares Fable 5's specs and pricing, offered separately for defensive cybersecurity workflows to organizations verified through Anthropic's verification programs — originally the invite-only Project Glasswing. Since October 6, 2026 the way in is an application to the Cyber Verification Program, and what its tiers grant is Mythos 5.1, not this model. Customers without access should use Fable 5.1. |
Model IDs are exact; tiers and 'best for' are guidance. Pricing, context-window sizes and rate limits change frequently and are intentionally NOT listed here — always read them on the official page above. This file is the single source of truth: never hard-code model facts in prose, link to this table instead.
Provalo: quale modello fa al caso tuo?
Rispondi a tre domande e ottieni un consiglio di partenza:
Scelta del modello
Difficoltà del task
Cosa conta di più
Volume di richieste
Recommended
Claude Sonnet
Il default bilanciato — ragionamento e coding di alto livello a una frazione del costo di Opus. Parti da qui e passa a un livello superiore solo se incontri un vero limite di qualità.
Trova l'ID esatto del modello nella tabella dei modelli. Solo una regola pratica — per esserne certo, esegui una rapida valutazione sui tuoi input.
Il modello mentale: una scala di capacità
- Parti da Sonnet. È il cavallo di battaglia predefinito — ragionamento e coding solidi a un costo ragionevole. La maggior parte dei task dovrebbe iniziare qui.
- Sali a Opus solo quando Sonnet fatica e la qualità conta più del costo (ragionamento difficile, agent complessi, codice ostico).
- Scendi a Haiku per lavoro ad alto volume, sensibile alla latenza o semplice (classificazione, estrazione, routing, sub-agent economici).
Come scegliere davvero
Guided walkthrough1 of 4
- È il cavallo di battaglia bilanciato. Partire da qualsiasi altro punto significa ottimizzare prima di avere prove sul tuo task reale.
- Non aggiornare l'intero carico di lavoro. Individua i casi in cui Sonnet fallisce e instrada solo quelli su Opus — compri la qualità senza pagarla ovunque.
- Classificazione, estrazione, routing e sub-agent economici raramente hanno bisogno di un modello più grande. Testalo invece di darlo per scontato.
- Usa Haiku per pre/post-elaborazione economica e Sonnet/Opus per il nucleo difficile. Questa stratificazione dei modelli è una delle leve di costo più importanti — vedi Costo e latenza.
La stratificazione dei modelli merita una lettura a parte: Costo e latenza.
Non scegliere solo dai benchmark
I benchmark pubblici sono un indizio di partenza, non un verdetto per il tuo task. Esegui una piccola valutazione su una manciata dei tuoi input reali confrontando due modelli — richiede pochi minuti e batte il tirare a indovinare.
Trovare l'ID esatto del modello
Passa sempre l'ID del modello API attuale (ad esempio nella tua chiamata messages.create). Recuperalo dalla tabella dei modelli qui sopra o dalla pagina ufficiale dei modelli — e preferisci leggerlo dalla configurazione invece di codificarlo in molti punti, così gli aggiornamenti del modello diventano una modifica di una riga.
Mettiti alla prova
0/4- Haiku → Sonnet → Opus è una scala capacità/costo/velocità — scegli un gradino, non tirare a indovinare un modello.
- Imposta Sonnet come predefinito e rilascia; sali o scendi solo con prove dal tuo task reale.
- Aggiorna il sottoinsieme difficile, non l'intero carico di lavoro — il routing batte gli aggiornamenti a tappeto.
- Combinare i livelli in un unico sistema è una delle leve di costo più importanti a tua disposizione.
- I benchmark sono un indizio; una piccola valutazione sui tuoi input reali è il verdetto.
- Leggi l'ID del modello dalla configurazione e cercalo nella tabella dei modelli aggiornata — non codificare mai fatti sui modelli.