Host baseline probe privacy follow-up: login-bearing version suffixes, home traversal per line, path-only normalization, distinct subtest ids - #748

Scope

• What this PR changes: the host baseline probe's privacy follow-up to Host baseline recorder: read-only probe and receipts for the 24.04 and 26.04 hosts (guard unit A PR-0) #710. It addresses the three P2 residuals accepted at Host baseline recorder: read-only probe and receipts for the 24.04 and 26.04 hosts (guard unit A PR-0) #710's merge and two leak paths.
  • Claude version strip. It no longer erases prerelease or build suffixes, so the login-name checks see them. A banner such as 2.1.289-<login> (Claude Code) is refused.
  • Home normalization. Absolute values with a .. component are refused, checked per line. Values are normalized lexically with posixpath.normpath only when single-line and whitespace-free. Every other value keeps its remainder verbatim after the home prefix is replaced.
  • Subtest ids. The sibling-home subtests have distinct ids, with a committed regression for it.
  • Docs. The guide states exactly where whole-document detection holds: for homes under /home/.
• Base: the Host baseline recorder: read-only probe and receipts for the 24.04 and 26.04 hosts (guard unit A PR-0) #710 merge ec0b8fd82. The four source files are unchanged on main since then; manifests/evidence.json is refreshed at landing (hot-file protocol).
• Lane: lane:foundation.

SOTA sources

• CPython posixpath.normpath: lexical normalization that resolves no symlinks.
• str.splitlines and str.isspace: the Unicode line-boundary set is a subset of whitespace, verified across all code points.
• The Host baseline recorder: read-only probe and receipts for the 24.04 and 26.04 hosts (guard unit A PR-0) #710 decision record, docs/decisions/2026-10-04-host-baseline-recorder.md, and its accepted residuals.

Evidence-class table

Local commands run

$ python3 -m unittest tests.test_host_baseline_probe   OK (28)
$ python3 scripts/validate.py                          exit 0
$ python3 scripts/evidence_manifest.py --check         exit 0
$ git diff --check                                     exit 0

Review

Built by GPT-6.1 Sol through the packaged SDK worker (rounds baseline-privacy-r5 and r6, on the #710 builder thread) and committed by the coordinator (Claude session 5f).

• r5: the Claude Opus cross-family read returned ACCEPT with 3 P2s. All were fixed in r6.
• r6: the Opus delta read returned ACCEPT and confirmed all 4 prior items fixed. It raised one new doc-only P2, recorded as a residual below.

Checklist

• No GitHub Actions or workflow changes.
• No secrets printed, logged or committed.
• No new paid hosting, subscription or billing surface.

🤖 Generated with Claude Code

Recorded residuals (Claude Opus 5.5 delta read at c9ec642)

• P2 (documentation only; non-blocking). tools/adoption/host_baseline_probe.py:204-206; tools/adoption/host-baseline.md:69-75.
  • The case: values that contain whitespace are no longer normalized. So for a home outside the /home/ tree, a leading home reference that is spelled non-canonically (a doubled slash or a . component) in a value that also contains whitespace or a line break is neither converted nor caught. The previous head normalized it.
  • Exposure: hosts whose homes are under /home/ are not exposed, since the home-prefix gate refuses such values with exit 3.
  • Suggested fix: one guide clause naming this case for homes outside /home/. No code change.