Run 1 Foundation — Byproducts

Date: 2026-04-01

Discoveries

1. ESLint Dual TSConfig Pattern

ESLint 9 with typescript-eslint strictTypeChecked requires all linted files to be included in a tsconfig. The build tsconfig excludes tests and root config files. Solution: a tsconfig.eslint.json that extends the build config with "include" expanded to cover tests and root files, plus "noEmit": true. The eslint config file itself needs disableTypeChecked to avoid self-referential linting.

This pattern should be documented in the typescript-coding skill for reuse.

2. no-unnecessary-type-parameters Shapes API Design

The original api-mcp code uses generic TInput parameters on base class methods. Under strictTypeChecked, ESLint flags these as unnecessary when the generic is only used once. The correct pattern: use unknown at the HttpClient helper level and enforce types at the proxy method signature.

3. Prettier YAML Formatting

YAML files with --- document start markers get reformatted by Prettier (single quotes changed, indentation adjusted). Always run prettier --write on workflow files before committing — don’t assume hand-written YAML is Prettier-compliant.

Learnings Applied

• Created typescript-coding skill in workspace capturing discoveries 1–3.
• Created typescript-engineer agent profile for future TypeScript package work.