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Sweep 22 Sep 2026 · 17:19Z Build v2.1.280 501 read Stable v2.1.267 Latest v2.1.280 Next v2.1.280 Feeds RSS JSON llms.txt Unofficial
Home Docs Claude Code CLI 22 Sep 2026
One change · claude-code

Claude Code on Google Cloud's Agent Platform changed

google-vertex-ai

Nearest release: v2.1.280, 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 22 Sep 2026 16:28 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 22 Sep 2026 16:37 UTC.

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From line 214 where the diff opens
First seen 14 Aug 2026 this site's first read of the page
Recorded edits9to this page, all time

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214214 
215215Set these environment variables to specific Google Cloud's Agent Platform model IDs.
216216 
217Without `ANTHROPIC_DEFAULT_OPUS_MODEL`, the `opus` alias on Google Cloud's Agent Platform resolves to Opus 5, and without `ANTHROPIC_DEFAULT_SONNET_MODEL`, the `sonnet` alias resolves to Sonnet 4.5. This example pins each alias to a specific version:
217Without `ANTHROPIC_DEFAULT_OPUS_MODEL`, the `opus` alias on Google Cloud's Agent Platform resolves to Opus 5.5, and without `ANTHROPIC_DEFAULT_SONNET_MODEL`, the `sonnet` alias resolves to Sonnet 4.5. This example pins each alias to a specific version:
218218 
219219```bash theme={null}
220220export ANTHROPIC_DEFAULT_OPUS_MODEL='claude-opus-4-8'
from line 228
228228 
229229| Model type | Default value |
230230| :--------------- | :--------------------------- |
231| Primary model | `claude-opus-5` |
231| Primary model | `claude-opus-5-5` |
232232| Small/fast model | `claude-sonnet-4-5@20250929` |
233233 
234234Background tasks such as session title generation use the small/fast model, normally a Haiku-class model. On Google Cloud's Agent Platform, Claude Code uses the default Sonnet model for background tasks because Haiku may not be enabled in every project or region. Two selections change which model carries them:
from line 240
240240 Opus models have a higher per-token price than Sonnet models, so a deployment that doesn't pin a primary model is billed at the Opus rate once it updates to v2.1.207 or later. To keep 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.
241241</Warning>
242242 
243On v2.1.207 through v2.1.218, the primary model on Google Cloud's Agent Platform defaulted to Opus 4.8 and the `opus` alias resolved to Opus 4.8. Before v2.1.207, the primary model defaulted to Sonnet 4.5, the `opus` alias resolved to Opus 4.6, and background tasks always used the primary model.
243Before v2.1.280, the primary model on Google Cloud's Agent Platform 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 Google Cloud's Agent Platform defaulted to Opus 4.8 and the `opus` alias resolved to Opus 4.8. Before v2.1.207, the primary model defaulted to Sonnet 4.5, the `opus` alias resolved to Opus 4.6, and background tasks always used the primary model.
244244 
245245To customize models further:
246246