Deprecate an HTTP Endpoint

Checklist for deprecating a backend HTTP endpoint. The runtime behavior (warn→error logging, response headers) lives in one shared middleware — you only wire it on and supply a date + replacement hint.

The authoritative policy is packages/backend/src/controllers/CLAUDE.md → "Deprecating Endpoints". This skill is the actionable checklist.

Scope — endpoints only

Only HTTP route handlers (TSOA controllers) get the deprecation middleware. Internal service/model methods, type fields, DB columns, and config fields are not endpoints — mark those with a plain @deprecated JSDoc and stop there.

First, check current state

Read the handler before editing. It may already have some of the pieces (@deprecated JSDoc, @Deprecated(), the middleware) — only add what's missing.

Precondition (hard blocker)

Only deprecate an endpoint once nothing first-party calls it anymore. The frontend, CLI, EE code, and other internal consumers must already be migrated to the replacement. A deprecated route logs an error once past its deadline, so any straggler caller becomes log noise.

Verify before touching the controller — search every first-party surface for the route path and its API hooks, including EE and test suites:

grep -rn "<route-fragment>" packages/frontend/src packages/cli/src \
  packages/common/src packages/backend/src/ee packages/api-tests packages/e2e

Watch for version differences: a v2 call (version: 'v2' / /api/v2/...) to a similar path is the replacement, not a caller of the v1 route. A test that hits the route counts as a caller — it will trigger error logs once past sunset. If any first-party caller remains, migrate it first (or stop — it cannot be deprecated yet).

Wire it up

In the controller, on the route handler:

Add the @deprecated JSDoc line naming the replacement. TSOA reads this tag to set deprecated: true in the OpenAPI spec.
Add the TSOA @Deprecated() decorator — the explicit, consistent way to mark it (decorator order doesn't matter). Keep both this and the JSDoc.
Rewrite the JSDoc description so its first line is plain text Deprecated — use the v2 <name> endpoint instead. (see "Make it visible in the docs" below for why this exact shape matters).
Add an @Extension('x-mint', ...) migration banner (same section below).
Add getDeprecatedRouteMiddleware to the handler's @Middlewares([...]) (use the same text for suffixMessage as the @deprecated JSDoc):

import { getDeprecatedRouteMiddleware } from './authentication';

/**
 * Get role assignments for a project
 * @summary Get role assignments
 *
 * @deprecated Use GET /api/v2/.../roleAssignments instead
 */
@Middlewares([
    allowApiKeyAuthentication,
    isAuthenticated,
    getDeprecatedRouteMiddleware(new Date('2026-06-08'), {
        suffixMessage: 'Use GET /api/v2/.../roleAssignments instead.',
    }),
])
@Deprecated()

Keep the existing description and @summary lines in the JSDoc (lint requires @summary on every endpoint) and append the @deprecated line after a blank line.

new Date(...) is the date you are deprecating it (today). The removal/sunset date defaults to deprecatedOn + 3 months; only pass { removeOn: ... } when a different sunset has been agreed.
If the handler has no @Middlewares block (e.g. some embed routes), add one containing just the middleware.

Make it visible in the docs (description + x-mint)

deprecated: true alone is nearly invisible on docs.lightdash.com — AI agents and scripts reading the docs keep generating code against the route. The docs site auto-generates API pages and llms.txt from packages/backend/src/generated/swagger.json (main branch), so docs visibility is wired here, in the controller JSDoc:

The llms.txt entry is - [summary](url): first sentence of description (truncated ~60 chars), and the description renders as the page subtitle. So the description's first line must be plain text (no markdown links, no MDX) leading with the deprecation:

/**
 * Deprecated — use the v2 Execute metric query endpoint instead.
 *
 * This endpoint was deprecated on <date> and will sunset on <date>. Migrate to
 * the v2 async query flow: Execute metric query, then Get results.
 * @summary Run metric query   // ⚠️ do NOT change — the docs page slug/URL is built from it
 * @deprecated Use POST /api/v2/projects/{projectUuid}/query/metric-query instead
 */

The visible banner on the endpoint page comes from the Mintlify x-mint: content OpenAPI extension (renders above the auto-generated reference; supports MDX). MDX in the plain description is NOT supported — don't put <Warning> there. Emit it with TSOA's @Extension (string must be a literal; backtick-escape inline code so {braces} don't break MDX):

@Extension('x-mint', {
    content: `<Warning>
**This endpoint is deprecated and will sunset on <date>.**

Migrate to [Execute metric query](https://docs.lightdash.com/api-reference/v2/execute-metric-query) (\`POST /api/v2/projects/{projectUuid}/query/metric-query\`), then [Get results](https://docs.lightdash.com/api-reference/v2/get-results).
</Warning>`,
})

Run pnpm generate-api and check the swagger.json diff: the operation keeps deprecated: true, summary unchanged, description starts with the plain-text Deprecated — ... sentence, and x-mint is present. Expect unrelated key-reordering drift in generated files — to keep the PR clean, revert generated files to HEAD, graft only the changed operation objects, then pnpm -F backend formatter --write ./src/generated/swagger.json.

Docs go live on the next mintlify-docs deploy after the backend change reaches main (the docs site re-fetches swagger.json from main at build time).

You get this for free

getDeprecatedRouteMiddleware (controllers/authentication/deprecation.ts) already does, per call:

Deprecation, Sunset, and legacy Warning response headers.
A warning log, escalating to an error log (GCP) once the sunset is within two weeks or has passed. Do not report DeprecatedRouteError to Sentry — it is in IGNORE_ERRORS and would burn quota on every call.

Do not add per-endpoint logging/headers. (Some older routes also fire a trackDeprecatedRouteCalled analytics event — that's optional; the middleware is the standard.)

Later: removal

Once the sunset passes (the route is now error-logging on every call), the follow-up task is to delete the handler and its route, then pnpm generate-api again. That's a separate change, not part of deprecating.

deprecate-endpoint