fix: bound anthropic<1.0.0 on the bedrock extra of uipath-langchain-client

[andreibalas-uipath]

What changed and why

Affected package: langchain only (uipath-langchain-client 1.18.0 → 1.18.1).

The bedrock extra had no direct anthropic requirement — it received the SDK only transitively:

• bedrock → langchain-aws[anthropic]>=1.4.5,<2.0.0
• langchain-aws[anthropic] (1.7.4) → anthropic[bedrock]>=0.95.0 — no upper bound
• langchain-anthropic 1.7.0 (2026-08-27) lifted its own anthropic<1.0.0 pin to >=0.120.0,<2.0.0

So any fresh resolution of uipath-langchain-client[bedrock] since ~2026-08-27 picked anthropic==1.2.0. The anthropic 1.x SDK moved to httpx2 and rejects the UiPath HTTP client at construction time in clients/bedrock/chat_models.py:

TypeError: Invalid `http_client` argument; Expected an instance of
`httpx2.AsyncClient` but got <class 'uipath.llm_client.httpx_client.UiPathHttpxAsyncClient'>

This broke every consumer resolving fresh — e.g. all uipath-langchain-python integration suites since 2026-08-29 (example run) and any end user running uv sync on a project using the bedrock extra.

Changes

• Add explicit anthropic[bedrock]>=0.96.0,<1.0.0 to the bedrock extra so the bound applies regardless of what transitive dependencies allow.
• Regenerated uv.lock (resolution unchanged — anthropic stays 0.96.0; only the new requirement metadata is recorded).
• Version bump 1.18.1 + changelog entry (langchain-only per repo convention).

Audit of remaining extras

Only bedrock had the gap. anthropic and all already carry the bound. vertexai uses plain langchain-google-vertexai (no [anthropic] extra), and google/azure/fireworks/litellm/openai have no anthropic in their closures. langchain-anthropic/langchain-aws themselves are deliberately NOT bounded — langchain-anthropic 1.7.0 still admits anthropic 0.12x, so bounding anthropic alone is sufficient and less restrictive.

Verification

Fresh (unlocked) resolution of the local package against PyPI:

• [bedrock] → anthropic==0.125.0, with langchain-aws==1.7.4 and langchain-anthropic==1.7.0 at latest
• [anthropic], [all] → anthropic==0.125.0
• [vertexai] → no anthropic in resolution

ruff check, ruff format --check, pyright, and pytest tests pass (the pre-existing local LLMGW_* env setup errors are identical on main).

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