Follow Discord
Sweep 27 Oct 2026 · 19:04Z Build v2.1.312 531 read Stable v2.1.308 Latest v2.1.312 Next v2.1.312 Feeds RSS JSON llms.txt llms-full.txt Unofficial
HomeDocsClaude Code CLI 27 Oct 2026
One change · claude-code

Claude Code on Amazon Bedrock changedamazon-bedrock

Nearest release: v2.1.312, published under an hour before upstream edited the page. Shown because the two are within 24 hours of each other. Nothing here says the release caused the edit.

Upstream edited this page at 27 Oct 2026 19:25 UTC, give or take a minute or two: the time comes from Anthropic’s own sitemap rather than from a commit. This site recorded the change at 27 Oct 2026 19:37 UTC.

Upstream edited
Recorded here
Lines+2added
Lines−2removed
From line 247 where the diff opens
First seen 14 Aug 2026 this site's first read of the page
Recorded edits35to this page, all time

The whole hunk

from line 247, old and new numbered
/
lines
from line 247
247247| Primary model | Opus 5.5, for example `us.anthropic.claude-opus-5-5` in a `us-*` region |
248248| Small/fast model | Sonnet 4.5, for example `us.anthropic.claude-sonnet-4-5-20250929-v1:0` in a `us-*` region |
249249 
250Before v2.1.280, the primary model on Amazon Bedrock defaulted to Opus 5 and the `opus` alias resolved to Opus 5 from v2.1.219.
251 
250252Background tasks such as session title generation use the small/fast model, normally a Haiku-class model. On Amazon Bedrock, Claude Code uses the default Sonnet model for background tasks because Haiku may not be enabled in every account or region. Two selections change which model carries them:
251253 
252254* When you select a primary model with `--model`, `ANTHROPIC_MODEL`, or the `model` setting, background tasks use that model. When Claude Code starts the session on the model you set with [`ANTHROPIC_DEFAULT_MODEL`](https://code.claude.com/docs/en/model-config#set-a-default-model-for-new-sessions), background tasks use that model too. Setting `ANTHROPIC_DEFAULT_OPUS_MODEL` without `ANTHROPIC_DEFAULT_SONNET_MODEL` also counts as a selection, because the built-in Sonnet model may not be enabled in an account that steers its own Opus.
from line 257
255257> [!WARNING]
256258>
257259> Opus models have a higher per-token price than Sonnet models, so if you don't pin a primary model, you're billed at the Opus rate. To use Sonnet 4.5 as the primary model, set `ANTHROPIC_MODEL` to its full model ID. A deployment that steers the default with `ANTHROPIC_DEFAULT_SONNET_MODEL` and doesn't set `ANTHROPIC_DEFAULT_OPUS_MODEL` keeps its steered Sonnet model as the default.
258 
259Before v2.1.280, the primary model on Amazon Bedrock defaulted to Opus 5 and the `opus` alias resolved to Opus 5 from v2.1.219. On v2.1.207 through v2.1.218, the primary model on Amazon Bedrock defaulted to Opus 4.8 and the `opus` alias resolved to Opus 4.8.
260260 
261261To customize models further, use one of these methods:
262262 
Feedback