Map Explorer To Mdim

Map an explorer's views to MDIM views (redirect proposal)

When an explorer is being retired in favour of one or more MDIMs, every explorer view needs a redirect to the equivalent MDIM view. This skill produces the input for that: a CSV of explorer views, a CSV per target MDIM, and a joint proposal mapping each explorer view to a target MDIM view (the suggestion is for human review).

The mapping itself is explorer-specific (how the explorer's dimensions translate to MDIM dimension slugs, and — when there are multiple MDIMs — which MDIM each view routes to). The skill automates everything mechanical (pulling views, the join, the shared-target accounting, validation) and leaves only the per-explorer rules for you to write, seeded with auto-suggested matches.

Inputs

• Explorer slug — matches explorers.slug in the grapher DB (e.g. natural-disasters).
• One or more MDIM catalogPaths — as stored in multi_dim_data_pages.catalogPath, e.g. natural_disasters/latest/deaths#deaths. The MDIMs must be published in the DB you connect to (their fully-expanded views are read from multi_dim_data_pages.config).

DB access (confirm this before running)

Both the explorer and the MDIMs are read from the grapher DB via OWID_ENV, so the scripts only work where that DB actually contains both the explorer and the published MDIMs. There are three ways to point OWID_ENV at such a DB — figure out which one applies before running, and don't assume .env.prod exists:

1. Staging branch (often easiest): if you're on a staging-site-<branch> branch, OWID_ENV already points at that prod-clone DB — run the commands as-is, no prefix.
2. Production, read-only, via an env file: prefix commands with ENV_FILE=<prod creds> DATA_API_ENV=production. Don't assume the file name — check what exists (ls -la .env*); on some machines it is .env.prod, on others .env.live.
3. Some other credentials file: the user may keep prod (or other) DB creds in a different env file — run with ENV_FILE=<their file> [DATA_API_ENV=production].

Preflight — check, then ask if needed:

ls -la .env* 2>/dev/null          # which credentials files exist?

# Connectivity test (swap the ENV_FILE prefix for whatever applies; drop it on a staging branch):
ENV_FILE=<prod creds> DATA_API_ENV=production .venv/bin/python -c \
  "from etl.config import OWID_ENV; print('DB OK:', OWID_ENV.read_sql('SELECT 1 AS x').iloc[0,0])"

If no prod credentials file exists and you're not on a staging branch with the data, stop and ask the user which credentials / env file to use (e.g. "which env file holds DB credentials that can reach the explorer + MDIMs? Or should I run this from a staging branch?"). Then use that file as the ENV_FILE= prefix for both script invocations below. Don't hardcode credentials.

If the connection works but a query returns nothing, the scripts stop with a clear message (explorer slug not found, or MDIM not published in this DB) — that means the DB you reached doesn't have it, so re-check which DB you're pointed at.

Workflow

1. Extract views + scaffold

.venv/bin/python .claude/skills/map-explorer-to-mdim/scripts/extract_views.py \
  --explorer <slug> \
  --mdim <ns/v/short#short> [--mdim <ns/v/short#short> ...] \
  --out ai/<slug>-mdim-mapping

Writes into the out folder:

• explorer_views.csv — id (1..N) + dimension_1..M (explorer display values).
• multidim_<short>_views.csv — one per MDIM; id is letter-prefixed by --mdim order (A1…, B1…, C1…) so ids are unique across MDIMs; columns are the MDIM dimension slugs.
• _scaffold.md — the explorer dimension legend (which dimension_i is which name), the distinct values per dimension, each MDIM's dims/choices, auto-suggested value matches (where a slugified explorer value equals a real MDIM choice slug), and a ready-to-edit mapping_rules.py template.
• _sources.json — machine-readable record of the explorer slug + dimension names and each MDIM's short/prefix/catalogPath/dim-slugs. Consumed by build_mapping.py to emit mapping.json (below); don't hand-edit it.

2. Write mapping_rules.py

Open _scaffold.md, then write ai/<slug>-mdim-mapping/mapping_rules.py defining:

• EXPLORER_DIMENSIONS — list naming dimension_1..N (copy from the scaffold; keep order).
• MDIMS — MDIM short names in the same order as --mdim (= prefixes A, B, C, …).
• route(dims) -> str — given a view's {dimension name: value}, return the target MDIM short name. For a single MDIM this is just return "<short>". For several, it's a decision on some explorer dimension (e.g. natural-disasters routes on Impact: Deaths→deaths, Economic damages (% GDP)→economic_damages, the rest→affected).
• translate(dims, mdim) -> dict — return {mdim_dim_slug: choice_slug} for the target MDIM view, built from the *_MAP dicts. Only include slugs the MDIM actually has (e.g. economic_damages has no metric — single-choice dims are pruned from MDIM views).
• (optional) DEFAULT_MDIM = "<short>" — the catch-all target for the bare explorer URL (see mapping.json → catchAll). Omit it and the best-fitting MDIM is chosen automatically (the one receiving the most resolved views; tie-break = earliest in MDIMS). Set it only when the automatic pick isn't the MDIM you'd want a param-less explorer link to land on.

The scaffold seeds the *_MAP dicts with slugify(value) guesses. Verify every entry — slugify won't catch label↔slug differences like Decadal average→decadal, Injuries→injured, Volcanoes→volcanic_activity, or aggregate collapses like All disasters/All disasters (by type)→all_stacked.

3. Build the proposal

.venv/bin/python .claude/skills/map-explorer-to-mdim/scripts/build_mapping.py --out ai/<slug>-mdim-mapping

Writes mapping_proposal.csv, one row per explorer view:

It also writes mapping.json — the machine record — and admin_bulk_payload.json, which is what you actually apply. The API exists: POST {admin}/api/multi-dim-redirects/bulk (handleBulkCreateMultiDimRedirects), also reachable from the Bulk-create redirects from JSON button on /admin/multi-dim-redirects. This endpoint is the only way to apply an explorer redirect: the CSV CLI that map-charts-to-mdim hands over (createMultiDimRedirectsFromCsv) accepts an /explorers/ source, but it writes no sourceQueryParams — so the row bakes as one unconditional rule and every view of the explorer 302s to a single MDIM view, per-view routing gone. Its Zod schema deliberately mirrors this file's catchAll + redirects shape, ignores keys it doesn't know (sourceViewId, viewId, mdim, stats, targets), and reports target: null entries as skipped.

Post admin_bulk_payload.json, never mapping.json. The payload has empty-valued source dimensions stripped out. That is mandatory, not cosmetic: a condition is matched against the incoming URL's params, and an absent param is not an empty string — so a condition of {"Period": ""} can never match, and every view carrying one silently falls through to the catch-all instead of its intended target. mapping.json keeps them because it is the faithful record of the view grid.

Unlike the CSV (positional dimension_N columns, meant for a spreadsheet), the JSON carries every identifier a redirect needs:

{
  "explorer": { "slug": "...", "dimensions": ["<name>", ...] },
  "targets":  [ { "mdim": "...", "catalogPath": "ns/v/short#short", "dimensions": ["<slug>", ...] } ],
  "stats":    { "total": N, "resolved": N, "unresolved": N },
  "catchAll": {                        // bare explorer URL (no query params) fallback
    "source": { "explorerSlug": "..." },
    "target": { "mdim": "...", "catalogPath": "ns/v/short#short",
                "viewId": null, "dimensions": {} }   // no params → the MDIM's default view
  },
  "redirects": [
    {
      "sourceViewId": 1,
      "source": { "explorerSlug": "...", "dimensions": { "<name>": "<value>", ... } },
      "target": {                       // null when unresolved
        "mdim": "...", "catalogPath": "ns/v/short#short",
        "viewId": "A2",                 // internal id, cross-references the CSVs
        "dimensions": { "<slug>": "<choiceSlug>", ... }
      },
      "sharedTargetSourceIds": [1, 29, 57],   // present only when >1 source shares this target
      "unresolvedReason": "..."               // present only when target is null
    }
  ]
}

The source view is identified by the explorer slug + dimension name→display-value (the explorer URL query params); the target view by the MDIM catalogPath + dimension slug→choice-slug (the MDIM URL query params). Unresolved views are kept with target: null so the API can see the full picture; a consumer typically skips them.

An unresolved view is not a view left alone. The endpoint reports target: null entries as skipped, so they get no rule of their own — and the catch-all constrains no params, so it matches them instead. Those URLs land on the target MDIM's default view, carrying the explorer's own params into the grapher URL, rather than on anything equivalent to the view that was asked for. Leaving views unresolved is a deliberate call (they may genuinely have no MDIM counterpart), never a no-op; preflight reports the count so it gets made on purpose.

catchAll is always present: it redirects the bare explorer URL (no query params) — and serves as the sensible fallback for any view a consumer doesn't route individually — to the best-fitting MDIM with no query params, which grapher renders as that MDIM's default view (hence viewId: null, dimensions: {}). The best-fitting MDIM is the one most views resolve to, or whatever DEFAULT_MDIM in mapping_rules.py overrides it to.

The catch-all's destination is the only one nothing pins. Its row stores viewConfigId = NULL, so it resolves at request time to whichever view the MDIM renders for an empty selection — the first view in config order (grapher's filterToAvailableChoices takes the first available view's choice at every dimension). Rebuilding the MDIM can reorder its views, or edit that view's config in place, and the bare explorer URL then lands somewhere nobody reviewed. Extraction records that view in _sources.json (not in the payload, which must stay byte-reproducible) and preflight warns when it moves. A warning, not a blocker: the destination is a moving reference by construction, so blocking would flip an approved catch-all to NOT READY on any unrelated MDIM rebuild. To pin it, give the catch-all an explicit target view instead.

The script prints a validation report: how many explorer views resolved, distinct MDIM views hit per MDIM, how many rows share a target, and FLAGS for any explorer view that didn't resolve to a real MDIM view (fix the rules and re-run until there are no flags).

4. Review

Sanity-check the flagged rows and the judgment calls (approximate type matches, aggregate collapses, MDIM choices with no explorer source). /review-explorer-mdim-mapping renders the pairs side by side with approve/flag controls for a topic owner; corrections go through mapping_rules.py and a rebuild, not the HTML.

5. Audit what references the explorers (ALWAYS offer; run when the user says yes)

ENV_FILE=<prod creds> DATA_API_ENV=production .venv/bin/python \
  .claude/skills/map-explorer-to-mdim/scripts/audit_references.py \
  --mapping ai/<a>-mdim-mapping --mapping ai/<b>-mdim-mapping \
  --out ai/<combined>-redirects

Writes references.csv + references.md across all the explorers in one pass. It resolves each referencing URL through the rules the payload would create, so every row says which view the reader lands on — and separates the link had no params from the link names a choice the explorer has since dropped, which lands on the MDIM's default view and needs authoring attention rather than a URL swap.

The timeline differs from the chart skill's, and this is the thing to say out loud: an embedded explorer breaks the moment the redirect is created, not later at unpublish, because the embed renders by fetching the explorer page and parsing it. So the 🔴 rows are migrated before step 7, not after.

The report also carries a ⭐ Featured metrics section — the one surface where this skill's usual "a link survives the 302" reasoning inverts. A featured metric is a topic-page slot held by URL, resolved only when Algolia indexes, matching pathname and exact params against published records. So it does not survive: it empties silently, and cannot be re-added once the explorer is gone. Hence step 5b.

5b. Swap the featured metrics (before the redirect — it cannot be undone after)

Work the ⭐ section of references.md, by hand at /admin/featured-metrics. These are editorial slots, so ask whoever owns the topic before repointing their rail.

Per row — add the MDIM view under the same tag and income group, drag it to the old ranking, delete the old row, then re-apply boost in search if it was on. One explorer view can hold several rows: the key is (URL, tag, income group). Full procedure: docs/guides/data-work/redirect-to-mdims.md.

Why here and not after step 7: creating the redirect darkens the explorer on the spot, and adding a featured metric requires a published slug. Once the redirect exists, no replacement is accepted and no record of the ranking survives. Unlike an embed, which breaks visibly, this fails quietly. The replacement is the bare MDIM view, not the redirect target — the admin strips reader params on paste and never validates the dimension params.

6. Preflight (read-only, gated)

ENV_FILE=<prod creds> DATA_API_ENV=production .venv/bin/python \
  .claude/skills/map-explorer-to-mdim/scripts/preflight.py \
  --mapping ai/<a>-mdim-mapping --mapping ai/<b>-mdim-mapping \
  --out ai/<combined>-redirects [--record ai/<combined>-redirects/bulk_redirects.json]

Mirrors every validation the endpoint performs, per explorer — because it memoizes its source-side checks and re-throws the cached rejection, so one source-level problem fails every entry for that explorer. Blockers: the explorer path is already a site-redirect source, or the target of one (the chain case); the slug collides with a chart's old slug; a target MDIM is missing or unpublished; the target /grapher/<slug> is itself a redirect source; two views share a source condition; the view fingerprint no longer matches the live explorer; the payload was not built from the extraction sitting beside it; redirects already exist that differ from the payload; or embedded references are outstanding. A missing references.csv is a blocker too — "never looked" must not read like "looked and found nothing".

Two of those checks exist because nothing else ties the payload to the run that produced it, and an aborted or skipped rebuild leaves a stale one in place. build_mapping.py writes mapping_proposal.csv and mapping.json before admin_bulk_payload.json, and aborts between them on duplicate conditions — so the artifacts a human reviews can describe one build while the payload about to be posted comes from another, with the fingerprint check none the wiser (it validates the extraction, not the rules). Preflight therefore checks both ends:

• the payload's source conditions against explorer_views.csv + _sources.json, which catches an extraction re-run with no rebuild at all;
• the payload as a whole against the transform of the mapping.json beside it, which is what catches a rebuild that aborted in between — including one where only the targets changed, invisible to any source-side check.

The reference gate is bound to live state the same way. audit_references.py records a referenceDigests entry per explorer in references_manifest.json; preflight re-runs the sweep and compares. Without that, the gate reads a CSV from an earlier run and cannot see a page that added an embed since, or an audit folder carried over from another migration — both of which would read as a clean audit while the redirect is about to break something live.

It also records mappingDigests, binding the audit to the mapping its advice came from. Every replacement URL in references.md is derived from the mapping, so rebuilding the mapping with different targets invalidates that advice while the explorer's own references — and so the reference digest — stay identical. This is the one staleness with no second chance: an operator who repoints an embed at the wrong view leaves it no longer naming the explorer, so no later sweep can ever surface the mistake. Preflight blocks on it before the reference gate reports.

!!! note "An audit folder predating a surface reads as drifted, and should" The digest hashes the findings, so adding a surface to find-chart-references invalidates every recorded referenceDigests — most recently when featured metrics were added. Preflight blocks on an audit folder from before that, which is correct: it really is missing rows. Re-run audit_references.py rather than reading it as a bug.

Unverifiable is a blocker, not a warning, in all three cases — no extraction pair, no mapping.json, no reference digest. A warning does not reach the exit code, so Ready would print over a report stating in plain words that the payload's provenance is unknown. Re-running extract_views.py / build_mapping.py / audit_references.py is the cheap way to clear any of them; posting an artifact nothing backs is not.

A retired explorer whose redirects are all live reports DONE and exits 0. That is the finished state, not an error. But retirement does not retire the target side: an MDIM that has since been unpublished, rebuilt, re-slugged or edited in place breaks redirects that are already in the DB, and no explorer row is left to notice it. So every target check runs for a retired explorer too, and a slug carrying any blocker is never reported DONE.

Non-zero exit means do not post anything.

7. Apply — the admin bulk endpoint (GATED, production)

[!WARNING] Creating the redirect darkens the explorer immediately. It is checked on every /explorers/* request, ahead of env.ASSETS.fetch, so it beats the baked explorer page and any _redirects entry, and fires while the explorer is still published. There is no staged rollout and no bulk undo — removal is one row at a time.

Paste each admin_bulk_payload.json into Bulk-create redirects from JSON at {admin}/multi-dim-redirects, one explorer at a time. Read the response positionally: every results[i].source is the same /explorers/<slug> string, so index 0 is the catch-all when present and index i is redirects[i-1]. Expect created + skipped + errors == entries.

Then wait for the bake plus ~2 minutes (the redirect map is fetched with a 2-minute edge TTL) and verify:

curl -sI "https://ourworldindata.org/explorers/<slug>?<one view's params>" | grep -i "^HTTP/\|^location:"
# expect 302 + location: /grapher/<mdim>?<view dims>

8. Retire the explorer, then its ETL step

The explorer is unpublished or deleted BY HAND in the admin. Removing the ETL step does not unpublish it — the explorers row survives, so it keeps showing up in listings and search. Do not flip isPublished in the step's .config.yml and re-run hoping to achieve it; that is not the route (and no explorer config in the repo carries isPublished: false).

Then remove the explorer's ETL footprint — and never delete a step without archiving it (see CLAUDE.md). Delete the step's .py and its sibling .config.yml (the periodic archive sweep only knows .py, which is why orphaned configs exist on disk today), remove the dag/*.yml entry, make check, commit; then run .venv/bin/etl archive-dag and commit dag/archive/*.yml separately, since it reads committed history. git checkout anything unrelated it sweeps in. Archive anything now orphaned upstream — a garden step that existed only to feed this explorer — in a second round. If any of those is a migrated/backport dataset, delete its now-orphaned snapshots/backport/latest/dataset_<id>_* mirror files too: archiving the DAG entry leaves them on disk, and nothing will point at them again.

Grep before deleting a shared explorer data step. Some are consumed off-DAG, by scripts fetching their published catalog CSVs by URL. Those consumers are invisible to .venv/bin/etl archive-dag, so the step looks like a safe leaf when it is not. Search for its catalog URL first and keep it until every consumer is retired.

Track these steps with TodoWrite in the chat. Do not generate a checklist file, and there is no HANDOFF.md for this skill — unlike the chart path there is no cross-team handoff, since the same operator pastes the payload.

What each run writes

Notes & gotchas

• MDIM views come from multi_dim_data_pages.config (published, fully expanded). This already reflects code-generated views (group_views aggregates) and pruned single-choice dimensions — so e.g. a metric that has only one active choice won't appear as a column.
• Many explorer views can redirect to one MDIM view — that's expected (the explorer often splits a concept the MDIM merges, e.g. a single-line "All disasters" total and a stacked-by-type view both mapping to the all_stacked MDIM view). shared_target_explorer_ids surfaces these so the reviewer sees the collisions.
• An MDIM may have choices with no explorer source (e.g. an …_excluding_extreme_temperature aggregate). Nothing redirects to those — fine, just confirm.
• Explorer dimension columns stay dimension_1..N (compact, and joinable to the explorer CSV); the name legend lives in _scaffold.md and in EXPLORER_DIMENSIONS.
• Re-running extract_views.py overwrites the CSVs and _sources.json but not your mapping_rules.py.
• mapping.json needs _sources.json; if you extracted before this output existed, just re-run extract_views.py once (it preserves mapping_rules.py), then build_mapping.py.
• One payload per explorer is a correctness requirement, not a convention: the endpoint's schema has a single catchAll, so a merged file would silently drop all but one.
• There is no bulk delete — only DELETE /api/multi-dims/:id/redirects/:redirectId, one row at a time. A 460-row batch posted wrongly is expensive to undo, which is why the preflight exists.
• Explorer redirects never reach _redirects (getRecentMultiDimRedirects excludes non-/grapher/ sources), so there is no static-redirect fallback and no one-week window — they live only in the baked redirect map.
• Matched source params are deleted from the outgoing URL and unmatched ones leak through. The target view's params win; country=, time=, tab= ride through untouched, which is what a reader following an old link wants.
• An explorer view's id is positional row order — a re-saved TSV renumbers every id that mapping_proposal.csv, the review HTML and sourceViewId key on. That is what viewsFingerprint detects; configMd5 is only a secondary signal, since it flips on any FAUST edit and gating on it would force a needless re-review.
• Algolia keeps indexing the explorer until the next index build, so it can still appear in site search after the redirect exists.
• Retiring the explorer row itself is separate from the redirect: deleting it makes linkedChart unresolvable, so Chart blocks render nothing and tiles vanish. The five WB/WID inequality explorers migrated in July are the worked example.