B-8IUO-retire-rust-frontmatter-validator-validate-frontmatter-via
Status: promoted/task
packages/rust/frontmatter-validator (validate-frontmatter bin, 271 LOC) has zero runtime consumers (only a Cargo workspace member) and its JSON-Schema-over-frontmatter check is a strict subset of the TS markdown-contract already load-bearing across apps/sdlc, solutions/determined, and packages/ts/agent-plugin. Remove the crate; route any frontmatter-validation gate (e.g. T-M2OV) through markdown-contract or its CLI. Derives from the augmented-convergence audit (docs/planning/analysis/augmented-convergence.md, axis 2).
Resolved by T-J5DI-remove-clear-duplicate-augmented-packages (PR #998). That task deleted packages/rust/frontmatter-validator after verifying zero runtime consumers — no build, CI, justfile, or moon-task depended on it.
The “route any gate through markdown-contract” clause has no live target. Its one named example,
T-M2OV-pre-merge-frontmatter-validation-gate, is closed/superseded, and its surviving citation
is to a Python validate_frontmatter.py, not to this crate. Nothing else consumed it, so the
removal completes this item rather than deferring work.