Module docstrings cite spec subsections that do not exist (§5.1, §4.2) or that do not define the cited concept (§15)

[nficano]

Category: docs Severity: minor
Location: src/arcp/_envelope.py:1 (+ class docstring), src/arcp/_transport/stdio.py:1, src/arcp/_extensions.py:1,7
Spec: ARCP v1.1 §5, §4, §15

What

ARCP v1.1 §5 (Wire Format) and §4 (Transport) have no subsections, so the references to "spec §5.1" (_envelope.py:1 and the class docstring at line 34) and "spec §4.2" (_transport/stdio.py:1) point at sections that do not exist. _extensions.py:1,7 attributes the x-vendor.*/arcpx.* extension-key namespaces to "spec §15", but §15 (IANA Considerations) defines no such extension-key namespace. The citations mislead readers cross-referencing the draft.

Evidence

"""ARCP wire envelope (spec §5.1): 8 fields, `arcp` constant, mutable pydantic model.

Proposed fix

Update the docstrings to cite §5 (wire format) and §4 (transport) without fabricated subsection numbers, and remove or correct the §15 attribution for the extension namespaces (which are an SDK convention, not a spec section).

Acceptance criteria

• Docstring spec references resolve to real sections that support the statement; no "§5.1"/"§4.2" citations remain and the extension-namespace claim no longer cites §15.