[abhinavrastogi2627]

The documented pip install 'conductor-python[agents]' leaves 43_react_agent_multi_model.py unable to import ChatAnthropic. Add optional langchain-anthropic>=1.5.5 to agents and expose a standalone langchain-anthropic extra. Update the extras table and regenerate the Poetry lockfile; resolving the new integration also updates the locked Anthropic SDK and LangChain Core versions.

Fixes #486. This is the standalone packaging change requested in #495.

Validation: clean .[agents] install, dependency compatibility check, and the affected example's model/graph construction passed with network access blocked. Built the wheel, verified optional dependency markers, and installed/imported its standalone extra in a second clean environment. Poetry lock validation and 2,671 unit tests passed (1 skipped). The full five-suite run has the same 2 failures and 48 errors as unchanged main (worker collection effects and integration setup requiring a local server); no new failures. Live server/LLM execution was not tested.

[abhinavrastogi2627]

Rebased onto the current main branch and regenerated the Poetry lock metadata, preserving the upstream dependency fixes. Validation: poetry check --lock passed; the full unit suite passed with 2,680 tests and 1 skip. The extras were also checked through clean wheel installs, dependency consistency checks, and offline construction of the Claude example model and graph.