returns

name	returns
description	Guardrail for dry-python/returns in pawrrtal. Use when an agent proposes Maybe, Result, IOResult, FutureResult, railway-oriented error handling, or adding the returns dependency.
paths	["backend/**/*.py","backend/pyproject.toml"]

returns for pawrrtal

dry-python/returns is not part of this backend. The backend restructure explicitly removed the dependency and chose idiomatic Python error handling instead.

Rule

Do not add returns, Maybe, Result, IOResult, or FutureResult to Pawrrtal code. Do not pin returns in backend/pyproject.toml, enable the returns mypy plugin, or wrap provider/chat/router contracts in railway containers.

Use the local patterns instead:

Need	Use
Route failures	HTTPException at the route boundary
Provider/runtime failures	Narrow exception classes plus clear SSE/error events
Optional database rows	`T
Validation	Pydantic models, typed helpers, and explicit exceptions
Async multi-step flows	Small helpers with try/except at the orchestration boundary

Review checklist

• Reject new from returns... imports.
• Reject Result[T, E], Maybe[T], IOResult[...], and FutureResult[...] signatures.
• Reject mypy plugin entries for returns.contrib.mypy.returns_plugin.
• If a proposal says "pilot returns", redirect it to a separate design discussion before code changes.

The previous pilot notes are archived in git history; they are not an active implementation plan.