context-guard / rate-limit-guard: durable statusline wiring (version-independent shim)

[kyle-sexton]

Problem

Both guard plugins tell the operator to wire bash "<plugin-root>/scripts/statusline-tee.sh" <their statusline> into settings.json. ${CLAUDE_PLUGIN_ROOT} is version-pinned (~/.claude/plugins/cache/<marketplace>/<plugin>/<version>/) and the old version directory is pruned ~14 days after an update (plugins reference, "Plugin cache and file access", fetched 2026-07-24). So that wiring:

1. stops teeing silently at the next version bump (the old tee still runs until pruned), and
2. breaks the operator's whole statusline once the old directory is pruned — bash <missing-path> exits 127 and the wrapped statusline never runs.

setup check detects (1) only on demand, and an interim [ -f … ] existence guard fixes (2) but not (1).

Decision

Ship a version-independent shim in both plugins (scripts/statusline-shim.sh), installed by setup apply to ~/.claude/<plugin>/bin/statusline-shim.sh — inside each plugin's already-accepted operator-home carve-out. The operator wires the shim ONCE; it resolves the newest installed tee at run time, so version bumps need no re-wiring, and it degrades transparently when no tee is installed (including after uninstall).

Rejected alternatives: keep the interim guard (still stops teeing on every bump); inline the resolution glob in settings.json (untestable shell frozen in an operator file, unreadable once two tees chain); a ${CLAUDE_PLUGIN_DATA} home for the shim (deleted on uninstall — reintroduces the 127 failure — and hardcodes the marketplace name into operator settings).

Scope

• scripts/statusline-shim.sh + statusline-shim.test.sh in context-guard and rate-limit-guard
• setup apply installs the shim (widens context-guard's apply scope; gives rate-limit-guard an apply for the first time); setup check gains an installed-shim state and reclassifies cache-path wiring as LEGACY
• Delta security review recorded in docs/MIGRATION-PLAYBOOK.md (new write surface: an inert, byte-identical copy of reviewed bundled code)
• Sibling-composition wiring (both tees chained, each through its own shim) documented in both setup skills, with the measured per-tee refresh cost
• Resolves the plugin-audit-port PLAN open question "stable-shim (stress-test ci: onboard to the CI platform (ci-workflows + standards) #4)"

Statusline wiring itself stays print-only — the plugin never edits settings.json.

[kyle-sexton]

This was generated by AI during triage.

Verified — already in flight

PR #1252 is open and carries Closes #1251. Its file list matches this item's Scope section closely:

• plugins/context-guard/scripts/statusline-shim.sh + .test.sh
• plugins/rate-limit-guard/scripts/statusline-shim.sh + .test.sh
• both skills/setup/SKILL.md and both evals/evals.json
• docs/MIGRATION-PLAYBOOK.md (the delta security review this item's Scope requires)
• docs/topics/plugin-audit-port/PLAN.md (the "stable-shim (stress-test ci: onboard to the CI platform (ci-workflows + standards) #4)" open question this item says it resolves)

This is not raw intake needing a brief — the item body already carries its own Decision section with rejected alternatives, and the work is authored and open for review.

Classification

• Work class: C3 scoped, feature-shaped — new scripts plus a widened setup apply write surface into the operator home carve-out.
• Disposition: human-gated. Per the admission gate, C3 feature-shaped is human-gated (operator tightening, permitted without justification). It is moot in practice here: the PR is human-authored and human-merged, and /work-items:work's frontier filter independently excludes items with an open closing PR, so this was never autonomously re-pickable.

No brief written — the item is fully specified by its own body and superseded by the open PR. Raw marker cleared so it stops re-entering the intake sweep every cycle; it will close on PR merge via the closing keyword.