Feature implementation

The repeatable path for shipping a feature here, derived from how /economy / the Status Paper were built. Pair with arch-discovery (where things live) and data-discovery (sourcing the numbers).

The loop

1. Model the data in data/types.ts. Reuse existing types where possible (e.g. KpiTimePoint for any time-series). Mark optional *Ml fields.
2. Write the fixture in data/<thing>.ts — a typed array. Every published figure carries source + sourceUrl to an official government document (data-discovery skill, docs/data/source-policy.md).
3. Wire the KV layer in data/db.ts: add the ["<thing>", id] prefix to the layout comment + the seed() wipe-list + the seed loop, add put*/list*/get* accessors, and bump SEED_VERSION.
4. Project into the knowledge graph (only if the entity relates to existing entities — a leaf with no relationships skips this). Add <thing>Node + <thing>Edges builders and a sync<Thing>Graph to lib/graph.ts, wire the prefix into buildGraph(), and call the sync from your putIngested* writer. Full recipe + the "silently dropped edge" gotcha: docs/specs/knowledge-graph.md.
5. Build the route/component under routes/** / components/**. Server-render by default; add an island only for real client interactivity. Use define.handlers + define.page, t(lang, …)/pick, and the CSS tokens in static/styles.css. For visuals, prefer SSR SVG / daisyUI over a chart library (see components/MetricChart.tsx).
6. Bilingual. Provide verified *Ml for new strings. If you can't verify a Malayalam government term, leave it unset and set dataStatus: "tbd" — never guess. Run /bilingual-audit.
7. Nav. Add the entry to components/Header.tsx if it's a top-level page.
8. Verify. deno task check (fmt + lint + type-check) and deno task check:sources. For data changes, run the relevant reviewer agent (kpi-data-reviewer / governance-data-reviewer). Smoke-test with deno task dev and, for visuals, a screenshot.

Gotchas

• The deno fmt PostToolUse hook rewrites files on save — re-read before a second edit or the next edit's old_string won't match.
• Forgetting the SEED_VERSION bump = the site silently serves stale KV data.
• A graph edge whose target node isn't projected yet is silently dropped (no dangling edges by design) — seed/rehydrate nodes before buildGraph() runs.
• Lang is exported from data/lang.ts, not data/types.ts.
• JSX lists need a key prop (Fresh lint rule jsx-key).

Definition of done

deno task check + deno task check:sources green · SEED_VERSION bumped · bilingual parity (or tbd) · every figure government-sourced · a spec note in docs/specs/ for non-trivial features.