port-python-parity

Port Python SDK changes to this Ruby gem. Target version(s): $ARGUMENTS (if empty, find the latest unported Python version via gap analysis below).

Source of truth

• Python SDK checkout: ../claude-agent-sdk-python (relative to this repo). Pull latest before starting.
• Repo-local parity record (primary, always available): the README parity comparison table and CHANGELOG.md — update both whenever a feature lands.
• Auto-memory files project_porting_pattern.md and project_parity_gaps.md hold the last-checked version and history (supplementary — they may be absent in fresh environments; if missing, derive the last ported version from CHANGELOG.md instead).
• When citing a fact about this gem (dependency bounds, config defaults, API shape), verify it against the code (gemspec, lib/) — not against CLAUDE.md, README prose, or memory, which can lag the code.

Workflow

1. Gap analysis — diff the Python SDK between the last ported version and the target: read its CHANGELOG.md and git log for the range. Verify the version tags actually exist first (git tag -l) — Python's versioning has jumped ranges before (v0.1.81 → v0.2.82). List each change as port / adapt / skip (Ruby-N/A), with the Python PR number.
   • Don't classify a PR by its label — read its full diff. A PR that looks Ruby-N/A on the surface (asyncio/anyio plumbing, CI changes, type annotations) often carries embedded behavioral changes that DO apply: e.g., Python #990 was "trio compatibility" but also simplified flush() semantics and narrowed exception swallowing. For each skip verdict, enumerate the semantic changes inside the diff and confirm each one is already matched (or genuinely N/A) in the Ruby counterpart files, citing file:line.
2. Branch — feature/sync-python-sdk-<python-version> (e.g., feature/sync-python-sdk-0.1.56). Batch-style audit work uses audit/<topic>-batch-<n> instead.
3. Port — adapt Python idioms to Ruby conventions:
   • snake_case names, keyword args, plain classes with attr_accessor (no Struct/Data)
   • to_h serialization with camelCase keys for CLI compatibility
   • user-facing callbacks must go through FiberBoundary.invoke
   • RSpec expect syntax only; add specs mirroring the Python tests
4. Commit messages — reference the Python PR number, e.g. Add local-disk list_subagents (Python #825).
5. Verify — bundle exec rake (spec + rubocop) must be green. Run RUN_INTEGRATION=1 bundle exec rspec if the change touches the CLI wire protocol.
6. PR — title references the Python SDK version; body lists each ported change with its Python PR number.
7. Record — update the README parity table, CHANGELOG.md, and the memory files (new "last ported" version, anything skipped and why).

Known traps from past batches

• The mcp gem's API has shifted between minor versions — verify against the locked version, not docs.
• Enumerator-based streaming input crosses threads; watch for FiberError (see fiber_boundary.rb docs).
• Some Python features are CLI-version-gated — prefer version-independent detection (in-band errors over version sniffing).