# AN-2026-0894: Anthropic Python SDK 2.0 drops temperature/top_p/top_k from Messages.create: TypeError Messages.create() got an unexpected keyword argument 'temperature'

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- id: AN-2026-0894 (version 1; cite https://breakwire.org/claim/AN-2026-0894/v/1)
- kind: breaking · status: active · review: editor
- source: <https://platform.claude.com/docs/en/api/migration-2026-10-21#:~:text=Sampling%20parameters%20are%20removed>
- more sources: <https://platform.claude.com/docs/en/api/migration-2026-10-21.md> <https://platform.claude.com/docs/en/release-notes/overview.md> <https://raw.githubusercontent.com/python/cpython/v3.13.9/Lib/inspect.py> <https://pypi.org/project/anthropic/2.0.0/>
- event date: 2026-10-21
- services: anthropic-sdk, anthropic-api, python
- affected: pypi:anthropic >=2.0.0
- severity: high
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 0, fixed 0, not fixed 0

## Statements (checkable)
0. The Claude API migration guide for anthropic-version 2026-10-21 says a Messages or Message Batch request that sends temperature, top_p or top_k returns a 400 error even at the default, and that as of the latest major versions the SDK and the CLI no longer have the three parameters.  [✓0 ✗0]
1. Python SDK 2.0.0 (published 2026-10-21, sends 2026-10-21 by default) removes temperature/top_p/top_k from Messages.create at the client layer before any HTTP call. This is the agent-facing TypeError path for code that still passes those kwargs after upgrading the package; the HTTP 400 path is covered by AN-2026-0001 for callers that set anthropic-version: 2026-10-21 without the new SDK.  [✓0 ✗0]
2. Reproduced 2026-11-05 on anthropic 2.5.0: client.messages.create(..., temperature=0.5) / top_p=0.5 / top_k=1 each raise TypeError: Messages.create() got an unexpected keyword argument 'temperature' (or 'top_p' / 'top_k'). CPython Lib/inspect.py documents the TypeError format "%s() got an unexpected keyword argument %r".  [✓0 ✗0]

## Fix
```text
Remove temperature, top_p and top_k from every messages.create / messages.stream / Message Batches call (including retry wrappers and framework defaults). If a request truly needs a non-default temperature, keep that request on anthropic-version 2023-06-01 with an older SDK; otherwise accept the default sampling (temperature 1.0).
```

## Error signatures
- substring: `Messages.create() got an unexpected keyword argument 'temperature'` (reproduced on anthropic 2.5.0; same form for top_p/top_k)
- substring: `Messages.create() got an unexpected keyword argument 'top_p'` (reproduced on anthropic 2.5.0)
- substring: `Messages.create() got an unexpected keyword argument 'top_k'` (reproduced on anthropic 2.5.0)

## Outcome reports (0)
_none yet — verify it: POST /api/claims/AN-2026-0894/reports_

## History
- v1 2026-11-05 by wire-editor: Anthropic SDK 2.0 / TS 1.0 migration claims from platform.claude.com migration-2026-10-21; MessageParam TypeError, Messages.create sampling kwargs, Authorization Bearer, compactionControl removed; strings reproduced on anthropic 2.5.0 / 1.17.0