If you are choosing a model today, this page will probably talk you out of Claude 3.5 Sonnet. That is not a criticism of the model. It is arithmetic.
Claude 3.5 Sonnet arrived in October 2024 and became the model a lot of engineering teams first trusted with real code — not autocomplete, but actual edits to files that shipped. It earned that reputation. The problem is what it costs now relative to what has replaced it.
The number that constrains it
Context is 200,000 tokens. Maximum output is 8,192 tokens.
That second figure is the one that bites. Eight thousand tokens is roughly a long file — perhaps six hundred lines with comments. Ask for a full test suite, a migration script, or a rewritten module and it will stop mid-thought. You end up chunking the request and stitching the pieces, which is exactly the work you hoped to avoid.
The large context with the small output is a lopsided shape: it can read your repository but cannot write much back.
The pricing problem
Claude 3.5 Sonnet runs around $3.00 per million input tokens and $15.00 per million output tokens.
That is the same rate the current Sonnet generation carries. Same price, roughly five times the context, and an output ceiling measured in six figures rather than four. There is no budget argument for staying, which is unusual — normally the older model is at least cheaper.
Where it still makes sense
Two situations, both legitimate.
The first is inertia with evidence. If you have prompts tuned against this model, evaluation suites built around its behaviour, and output you have learned to trust, that accumulated knowledge has real value. Migrating means re-validating all of it.
The second is pinned reproducibility. Some teams need a fixed model snapshot for audit or regression reasons and cannot accept behavioural drift, whatever the improvement.
Outside those, the case is thin.
What to check before you commit
Claude 3.5 Sonnet no longer appears in Anthropic's current model line-up, and it is absent from the legacy table as well. Treat availability as something to confirm rather than assume — particularly if you are building something with a multi-year life, where a retirement notice mid-project is an expensive surprise.
Specifications
| Field |
Value |
| Provider |
Anthropic |
| Context window |
200,000 tokens |
| Maximum output |
8,192 tokens |
| Input |
text |
| Output |
text |
| Indicative pricing |
$3.00 in / $15.00 out per million tokens |
| Weights |
Closed |
| Released |
22 October 2024 (v2) |
Pricing and availability move, and this generation is old enough that both deserve a check against your own account before you plan around them.
Browse current alternatives in the AI model directory, or look at Gemini 2.5 Pro if the constraint you are trying to escape is that output ceiling.