Claude Code v2.1.248 · 27 Aug 2026
Per-surface context limits for claude-sonnet-5
Context limits for claude-sonnet-5 are 500,000 on two surfaces and a million elsewhere.
Under the hood Tier: how much it should matter to you
3 Useful: my rating, 1 to 5
4 Signal: worth watching, 1 to 5
Models Area: what it touches
In Development Kind: in v2.1.248, 27 Aug 26
What probably matters to you Section of the release
What
A limits table keyed by surface gives claude-sonnet-5 a 500,000 context default on the remote-cowork and local-agent surfaces and 1,000,000 everywhere else. Nothing visible gates the table itself.
Evidence
remote_cowork
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
See this entry in the whole of v2.1.248 →
27 Aug 2026 · 876 entries, this one is #63.
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Names in this entry
model claude-sonnet-5 Sonnet 5's default context window is now a full million tokens, up from 967,000.
model claude-sonnet-4-6 Context limits for claude-sonnet-5 are 500,000 on two surfaces and a million elsewhere.
model claude-opus-4-6 Opus 5 is now the default Opus, with a 1M-context option in the model picker.
model claude-opus-4-8 Opus 5 is now the default Opus, with a 1M-context option in the model picker.
model claude-opus-5 Opus 5 is now the default Opus, with a 1M-context option in the model picker.
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Related
Other releases about the same thing. Found by shared names or similar wording; neither means one caused the other.
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