🌿 Fern Regeneration -- March 30, 2026

[fern-api]

This PR regenerates code to match the latest API Definition.

Warning

CI is failing due to RecursionError in 90 type files. See issue #753 for full analysis.

The new arithmetic operator AST node types (add, sub, mul, div) added to the OpenAPI schema expand every discriminated union in the AST operator graph, pushing Python's forward reference resolution past its recursion limit. This is a known issue: it was previously hit and fixed manually in PR #658 (branch fern-support/fix-recursion-error), but that fix was never added to .fernignore and has since been overwritten by subsequent regenerations.

The fix needs to be re-applied and made sustainable before this PR can merge. See issue #753 for the proposed approach.

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Note

Medium Risk
Primarily a generated SDK/documentation update plus dependency/version bumps, but it may change client request/response shapes (e.g., workflow expression types and new query parameters), which could be a breaking change for consumers.

Overview
Updates the Python SDK to v2.41.0 and refreshes dependencies (including tomli 2.4.0 → 2.4.1).

Regenerates reference.md to reflect the latest API definition, notably adding/expanding the Music surface (e.g., client.music.compose, compose_detailed, stream, upload) and updating various API docs/parameters (e.g., new sort_by for message search and additional fields like branch_id/environment in conversational AI-related requests), along with revised workflow expression model types in examples.

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[kraenhansen]

Closed in favour of #754