Proposal (rationale)

The disposable Arena Lab canary run by WI-090 on 2026-09-06 (producer 675780c7, consumer f4ede793) failed one gate on an untouched, freshly scaffolded consumer: adr-index-current reported that docs/adr/README.md “lists 1 row(s) for 0 source file(s)”. The one row is | — | *none yet* | | |, the placeholder the adr module’s own template ships. The file-index rule WI-087 implemented counts every pipe line that is not a separator as a data row, so every consumer with the module installed and no decision yet fails its first check, through the installed CLI and after ejection alike. The producer never saw it: its own repository has eleven decision records, and the fresh-scaffold test asserts only the findings gate.

Decision

accepted — 2026-09-06 under WI-085, as work discovered by WI-090’s canary rather than a widening of WI-090. A candidate that fails a fresh consumer’s untouched scaffold cannot be handed to the release flow; the fix is small and bounded.

Plan

Requirements

• A file-index block whose only row is the — placeholder counts zero rows.
• render on zero sources emits the placeholder row rather than a header alone, so an untouched scaffold and its first render agree byte for byte, and a second render changes nothing.
• The shipped adr template block is exactly what render writes for zero sources.
• A self-test fixture covers the placeholder-only, zero-source pass direction.

Impacts

• src/engines2.ts (renderFreshness), src/render.ts (renderDerivedBlocks), src/selftest.ts (index builder), modules/adr/files/{{path}}/README.md, modules/adr/gates/adr.toml, modules/adr/module.toml (1.2.0 → 1.2.1), test/core.test.js, the site claims snapshot if it records module versions.

Approach

Exclude rows whose first cell is — from the count; emit that row from render when there are no sources; make the template match. Alternatives: teach the template to ship an empty table (loses the readable “none yet” line every consumer sees first) or special-case *none yet* text (fragile; the first-cell dash is the convention the board and findings register already use).

Acceptance criteria / tests

1. The engine test seeds a placeholder-only index beside zero records and asserts pass; a placeholder beside one record still fails; render on zero sources writes the placeholder and a second render writes nothing.
2. The new adr-index-current fixture (placeholder = true, source_files = 0, expect pass) executes in the inventory with no unrun or error outcome.
3. A fresh init tracked scaffold passes check with no render in between.
4. The serial suite, rungs check, and the site claims check pass.

Out of scope

• Any other gate the canary exercised; the eject summary wording that still says only check survives ejection is WI-092, opened separately from the same canary.
• Re-running the canary; WI-090 does that against the tree that includes this fix.

Execution

Branch feature/WI-091-index-placeholder-rows from 675780c7, 2026-09-06. One commit. As planned, with one addition forced by the repository’s own gate: module-commands-exist refused the template block once it carried render’s generated comment, because that comment named bare rungs render inside a module file. Rather than exempt it, render now names the consumer’s own command (node .ai/rungs.mjs render) in the comment it writes, and this repository’s docs/decisions/README.md was re-rendered so its comment matches. Also found on the way and recorded as a finding, not fixed here: check full means tier full through the ejected launcher and path full through the CLI (F-063).

Review

1. Engine test: node --test --test-name-pattern '^the table rules the fixtures exposed' test/core.test.js passes (1/1, 2026-09-06). It seeds the real template with {{path}}/{{id_prefix}} substituted, asserts pass beside zero records, asserts renderDerivedBlocks writes nothing, adds one record and asserts the fail message lists 0 row(s) for 1 source file(s), renders, asserts pass, removes the record, and asserts the rendered index is the template again.
2. Inventory (node .scratch/fixture-inventory.mjs, 2026-09-06): 163 fixtures, 161 ok, 2 unrun (the two named design-mirror-not-edited fixtures, F-062), 0 mismatch, 0 error — the two new fixtures execute.
3. Fresh scaffold: git init + node src/cli.ts init <dir> tracked + node src/cli.ts check <dir> with no render in between reports pass adr-index-current · 1 examined (2026-09-06). The scaffold’s one failure was backlog-merged-status because that scratch repository had no main yet — the producer’s fresh-scaffold test commits first and is unchanged.
4. Serial suite NODE_OPTIONS=--max-old-space-size=2048 node --test --test-concurrency=1 test/*.test.js: 152 tests, 149 pass, 0 fail, 3 skipped, 179 s (2026-09-06). node src/cli.ts check: 31 pass. Claims snapshot regenerated: 31 gates (+1 hook), run 31 pass 0 fail.