claude-sonnet-4-5-20250929
A Claude Code model, read out of the shipped bundle. No mined inventory carries it: everything below comes from what this site has written about it.
The dated first-party API id of Sonnet 4.5 (claude-sonnet-4-5 in Claude Code's model table), also used for the anthropic_aws, anthropic_google_cloud and gateway providers. On the first-party provider, when certain account checks pass, a startup migration rewrites a user-settings model of claude-sonnet-4-5-20250929 or sonnet-4-5-20250929 (with or without [1m]) to sonnet or sonnet[1m].
Not Anthropic's. Written by Claude Opus 5.5 from reading the v2.1.286 bundle, and it can be wrong.
In the changelogs
2Releases whose published page names claude-sonnet-4-5-20250929.
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v2.1.67
Automatic Sonnet 4.5 → Sonnet 4.6 Migration
found in this entry's text
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v2.0.0
Claude Sonnet 4.5 Model
found in this entry's text
First cited
0No release's published evidence quotes this name. The ledger indexes the Evidence lines of every changelog on this site, so this says nobody here has ever quoted it; it says nothing about how old the name is.
Presence across releases
0The miner has never read a build containing this name. It is here because a changelog entry of ours names it, which is evidence that it existed and not evidence of which releases carried it. The inventory starts at v2.1.138 and everything older than that was never mined.
Read out of the published npm bundle release by release, and out of Anthropic's own documentation as this site captured it. Nothing on this page is a description anybody here wrote about what the model does. All models.