The checker rejects canonical numeric string-literal indices on a statically typed primitive string.

const input: string = 'abc';
console.log(input['0'], input['3'] === undefined);

Strict TypeScript accepts this exact source. Node exits zero and prints a true. SharpTS rejects it at line 2 in both --no-tsconfig --noEmit and --no-tsconfig --strict --noLib --noEmit:

Index type '"0"' is not valid for indexing 'string'.

Both checker children exit 1 normally within their 20-second process-tree deadlines, with empty stderr and drained output. No interpretation, compilation, emission, assembly inspection or saved execution was attempted. The CLI output does not expose a numeric diagnostic code, so none is inferred here.

Found while validating #2798. Its complete stronger control independently rejects the typed quoted key '3' in both profiles; that whole source and its seven-line Node transcript remain preserved. #2798 owns runtime inherited-index lookup on an any receiver. #2799 owns runtime aliasing of noncanonical names. #2784 owns checker reads on actual Arrays; #527 is a closed keyof projection issue. Eight fresh all-state searches (all complete and untruncated) plus sixteen complete closest issue bodies and all comments found no focused owner for this primitive-string checker rejection.

Source lead: TypeChecker.Properties.Index.cs admits String/StringLiteral through the numeric-index branch, while the canonical string-literal special case handles Arrays only. The direct and delegated read paths have the same gap. Preserve precise string result types, noUncheckedIndexedAccess, invalid-name rejection and write checks. This is a source lead, not an introducing-commit claim.

Evidence: artifacts/p2-goal/2798-string-key-checker-node-oracle/canonical-quoted-string-indices.ts (SHA256 006C2BFE2E2EE6F5392D1346FDA43EBB79219A812555A163B037A1B3BBF0F3A7), fresh Node/strict reference results, and 2798-string-key-checker-current-proof/canonical-quoted-string-indices-results.json (SHA256 8D7FF940E2E4E2D1B244706C1C85B3BFB86D05755D35C7DD66BC98CEFA18B4BF). Owner audit: 2798-string-index-checker-owner-audit/assessment.json. Immutable CLI SHA256 ED665842B41DAE7A74D48CED3EAD012A5BDDE632F551CC778307E029C8FE94F4, corresponding to current clean commit 897033a580c0dc1c3c4c2c1e7842419c855d0d08; full runtime package and source hashes remained stable before and after each child. No production/test changes or project builds were made for this proof.