Carry-overs from the April 2026 TypeScript audit

[InfinityBowman]

Five items from packages/docs/audits/typescript-audit-2026-04.md are still open. That document remains the correct specification for each; this issue exists to keep them visible.

Status since April

Signal	Apr 2026	Sep 2026
as any	~144	109
as Record<string, unknown>	115	96
as Error	~100	101
satisfies	4	8
Type tests (expectTypeOf)	0	0
createServerFn	0	19 files
@ts-ignore / @ts-expect-error	3	0

Landed: typed-RPC migration, @types/google.picker, auth Zod parsing, the first pass on hot endpoints, and the admin type derivation in PR #768.

Still open

April item 5 (G1) -- type tests. Zero expectTypeOf / assertType calls repo-wide. Vitest supports this natively. Highest leverage of the five: type tests are what stop the rest of this backlog from quietly regressing between audits. 1-2 hours.

April item 4 (H1/G4) -- checklist registry as a discriminated map plus satisfies. Still Record<string, ChecklistMetadata> in checklist-registry/index.ts, which widens the keys to string and loses the AMSTAR2 | ROB2 | ROBINS_I union. 2-3 hours.

April item 3 (C1) -- admin and billing endpoints. 96 as Record<string, unknown> casts remain across 31 files. PR #768 handled the admin pages via createServerFn; the older hand-rolled endpoints did not move. Half a day.

April item 7 (G5) -- verbatimModuleSyntax: true. Still false in packages/web/tsconfig.json:12. Mostly lint-autofixable. 1-2 hours.

April item 8 (H4) -- server.ts env typing. Six as never / env as SentryEnv / env as DOEnv casts remain in packages/web/src/server.ts. Casting to never signals the binding type is too narrow at the source. 1 day, lower priority -- not actively dangerous.

---

Reference implementation for the type tests

cf-sync-engine already does this, in a repo we own. Three files carry 23 expectTypeOf / assertType assertions:

• packages/protocol/test/schema.test.ts
• packages/protocol/test/inference.test.ts
• packages/client/test/collection.test.ts

They mix runtime and type assertions in the same describe block (expect(() => defineSchema({...})).toThrow(...) alongside expectTypeOf), which is the pattern to copy -- no separate .test-d.ts harness needed, and no extra tooling beyond the Vitest already in use.

---

Part of #778 (TypeScript correctness target state and tracker).