Canonical change record

Anthropic Python SDK v1 introduces breaking runtime and API changes

Anthropic released Python SDK v1 on August 20 with Python 3.10+, httpx2, removed legacy APIs and sampling parameters, async raw-response parsing changes,…

Operational breakageRuntime failureActiveRevision 1
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Operational consequence

Admission State
admitted
Breakage Mode
Runtime failure
Consequence
Unpinned upgrades can fail at import, request construction, async response parsing or Bedrock client initialization. Python 3.9 environments cannot run v1.
Lifecycle
active
Materiality
critical
Record Class
Operational breakage

Affected subjects

Holds
  • Code
    Subject scope needs review
    Reason
    Exact last-compatible pre-v1 range and per-surface exclusions require retained package metadata.
Subjects
  • Affected Range
    >=1.0.0
    Ecosystem
    pypi
    Entity Id
    pypi:anthropic
    Exclusions
    • pre-v1 pins
    • direct API calls unaffected by Bedrock region default
    Identifiers
    • anthropic
    Regions
    • Claude API and AnthropicBedrock Python SDK integrations
    Surface
    sdk
Detection Technical and lineage detail

Detection

Matcher Holds
  • Code
    Detection needs review
    Reason
    Exact import, method, parameter, exception, and Python <3.10 failure signatures remain source-documented but not reproduced.
Signatures
  • Expected After
    Access
    v1 requires Python 3.10+, uses httpx2, removes deprecated surfaces, changes async raw-response parsing and errors when AnthropicBedrock has no AWS region.
    Status
    v1 breaking changes released
    Expected Before
    Access
    Python 3.9 and earlier SDK surfaces, httpx transport objects, legacy Text Completions and removed method parameters were accepted by pre-v1 releases.
    Status
    Pre-v1 SDK behavior
    Kind
    Package range
    Phase
    exposure
    Selector
    pypi:anthropic>=1.0.0
    Source Claim Id
    claim:ksr-anthropic-python-sdk-v1-2026-08-20:consequence

Before → after

After
Access
v1 requires Python 3.10+, uses httpx2, removes deprecated surfaces, changes async raw-response parsing and errors when AnthropicBedrock has no AWS region.
Status
v1 breaking changes released
Before
Access
Python 3.9 and earlier SDK surfaces, httpx transport objects, legacy Text Completions and removed method parameters were accepted by pre-v1 releases.
Status
Pre-v1 SDK behavior

Required action

Action
Pin the current SDK while preparing the upgrade; move to Python 3.10+, replace custom httpx objects with httpx2, remove legacy surfaces, update async parsing and configure an explicit Bedrock region before staging v1.

Next relevant date

Date role
Effective
Date
Status
Confirmed
Kingy reproduction Technical and lineage detail

Kingy reproduction

Limitations
Audit records source evidence only; no vendor API or paid reproduction test was run.
Status
Not tested
Sources and revision Technical and lineage detail

Sources and revision

Revision
Hash
sha256:13b79e3403199167e15ad86d663f24c323cb56555d025cfb95c9bef02d27df92
Number
1
Correction History
  • Action
    created
    Actor
    gate-d-audit-rehearsal
    Current Hash
    13b79e3403199167e15ad86d663f24c323cb56555d025cfb95c9bef02d27df92
    Reason
    Audited Gate D keep rehearsal.
    Recorded At
    2026-08-23T22:57:03.000Z
    Revision
    1