---
source: https://iinventedlight.com/library/notes/typescript-tsconfig.md
title: "What tsconfig.json does and how tsc finds it"
license: CC-BY-4.0
license_url: https://creativecommons.org/licenses/by/4.0/
source_license: "CC BY 4.0 (microsoft/TypeScript-Website); restated in our own words"
attribution: "Summary by iinventedlight (AI-assisted). Sources: Microsoft (TypeScript Handbook), TypeScript: Documentation - What is a tsconfig.json, CC BY 4.0 (microsoft/TypeScript-Website); TypeScript (Microsoft), TSConfig Reference, CC BY 4.0 (microsoft/TypeScript-Website)."
author: "iinventedlight (synthesis of cited sources); text drafted with AI assistance"
date: 2026-11-04
status: published
checked_on: 2026-11-05
as_of: 2026-11-05
confidence: medium
untested: "No code was run; only the fetched documentation pages were read."
category: coding-references
topic_area: "typescript: project configuration"
tags: typescript, tsconfig, compiler, configuration
sources:
  - id: S1
    title: "TypeScript: Documentation - What is a tsconfig.json"
    publisher: Microsoft (TypeScript Handbook)
    url: https://www.typescriptlang.org/docs/handbook/tsconfig-json.html
    accessed: 2026-11-05
    license: "CC BY 4.0 (microsoft/TypeScript-Website)"
  - id: S2
    title: "TSConfig Reference"
    publisher: TypeScript (Microsoft)
    url: https://www.typescriptlang.org/tsconfig/
    accessed: 2026-11-05
    license: "CC BY 4.0 (microsoft/TypeScript-Website)"
    license: "CC BY 4.0 (microsoft/TypeScript-Website)"
---
# TypeScript tsconfig.json

## Short answer
A `tsconfig.json` marks a directory as a TypeScript project root. It lists root files and `compilerOptions`. `tsc` walks up parent folders to find one unless you pass files on the command line. [S1]

## Points
- Command-line input files cause `tsconfig.json` to be ignored. [S1]
- Top-level fields include `files`, `extends`, `include`, and `exclude`. [S2]
- `compilerOptions` holds the type-checking and emit switches. [S2]

## Claims
- id: C1
  claim: tsconfig.json marks a directory as a TypeScript project root.
  source: S1
  evidence: "indicates that the directory is the root of a TypeScript project"
- id: C2
  claim: It specifies root files and compiler options.
  source: S1
  evidence: "specifies the root files and the compiler options required to compile the project"
- id: C3
  claim: tsc searches parent directories for tsconfig.json.
  source: S1
  evidence: "continuing up the parent directory chain"
- id: C4
  claim: Top-level tsconfig fields include files, extends, include, exclude.
  source: S2
  evidence: "files , extends , include , exclude and references"

## Sources
- [S1] TypeScript: Documentation - What is a tsconfig.json. Microsoft (TypeScript Handbook). https://www.typescriptlang.org/docs/handbook/tsconfig-json.html . License: CC BY 4.0 (microsoft/TypeScript-Website). Accessed 2026-11-05.
- [S2] TSConfig Reference. TypeScript (Microsoft). https://www.typescriptlang.org/tsconfig/ . License: CC BY 4.0 (microsoft/TypeScript-Website). Accessed 2026-11-05.

License: this note is CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Summary by iinventedlight (AI-assisted).

Source notice: TypeScript Handbook / Website docs © Microsoft. Licensed under Creative Commons Attribution 4.0 International (https://github.com/microsoft/TypeScript-Website/blob/v2/LICENSE).