fix(running-in-ci): make commit-SHA permalink rule unmissable

[tend-agent]

Summary

Strengthen the running-in-ci skill's guidance on permalinks for line references, after four fresh occurrences of blob/main/...#L42 line links in a single hour on max-sixty/worktrunk issue #2075, on top of one prior occurrence on issue #2072. The current wording ("Prefer permalinks...") is a soft preference buried in a bullet that co-lists the blob/main/... file-level form and the blob/<sha>/...#L42 line-reference form inside parentheses. Under cognitive load, the model anchors on the first form and pastes #L42 onto blob/main/... — producing a link that stays valid but silently starts pointing at different code once the surrounding file changes.

Evidence

Past hour on max-sixty/worktrunk — 4 occurrences across 2 sessions, all on issue #2075 ("Allow wt step aliases to change the parent shell's directory"):

1. Run 24285060091 — tend-triage on the newly-opened #2075. Session 242fb543-d70d-47e7-a0cd-5e3ce6ced53d.jsonl. The posted comment linked to blob/main/src/config/user/sections.rs#L528.

2. Run 24285659522 — tend-mention on #2075 (response to max-sixty's question about the implicit option). Session fa2b09a6-9e74-4997-9fb2-967990c765d1.jsonl. The comment linked three files via blob/main/...#L:

   • blob/main/src/commands/for_each.rs#L214
   • blob/main/src/commands/alias.rs#L282-L296
   • blob/main/src/output/global.rs#L227

Historical evidence from tracking issue #133 — 1 prior occurrence:

• Run 24280812931 — tend-triage on max-sixty/worktrunk#2072. Session c897d54c-17c7-44c1-a6dc-426c8813ce4b.jsonl. Comment linked blob/main/src/help.rs#L157-L162 to the very line that PR #2073 then rewrote (eprint\! → print\!).

Cumulative: 5 occurrences across 3 sessions and 2 issues.

Gate assessment

Gate	Result	Notes
Confidence (Gate 1)	PASS	High — consistent pattern across multiple sessions (5 occurrences, 3 sessions, 2 issues). Well above the 2–3 threshold for "consistent pattern."
Magnitude (Gate 2)	PASS	Targeted fix — rephrasing one prose sentence and splitting one bullet. Not a new section or structural change. Normal thresholds apply.
Classification	Structural-adjacent	The rule exists but the current framing lets the model conflate blob/main/... (for file-level) with blob/main/...#L42 (for lines). A sharper imperative removes that ambiguity. The replay test: if you replayed the same "paste a line ref into a comment" scenario 10 times, the current guidance would hit the same ambiguity every time — it's not a random model lapse.

The change

Prose sentence — from "Prefer permalinks (commit SHA URLs) over branch-based links for line references" (soft) to "Any link containing #L must use a commit SHA, never blob/main/...#L42" (hard rule, with git rev-parse HEAD named as the SHA source so the bot has an obvious next step rather than rationalizing main as "I don't have a SHA handy").

Bullet list — from the single co-listed Files bullet to two separate bullets, so the #L42 case can't be skimmed past:

• File-level link (no #L anchor): blob/main/src/foo.rs is fine
• Line reference: blob/<sha>/src/foo.rs#L42 — commit SHA required, never blob/main/...#L42

Test plan

• Diff reviews cleanly as a pure guidance rewrite (no behavior changes in generator or workflows).
• Future tend-triage and tend-mention runs that reference specific lines use blob/<sha>/...#L form.
• Watch tracking issue #133 for a decrease in new-occurrence count of this pattern.