🔍 tsconfig-inheritance-flattener-mcp

Your AI agent reads `tsconfig.json`. It has no idea what it actually means.

MCP server that resolves the full TypeScript config inheritance chain and returns the effective compiler options that actually apply — including everything inherited from extended base configs, monorepo packages, and node_modules presets.

🤔 The problem

Your agent reads tsconfig.json and sees:

{ "extends": "@tsconfig/strictest", "compilerOptions": { "paths": { "@/*": ["./src/*"] } } }

It has no idea that @tsconfig/strictest sets strict: true, noUncheckedIndexedAccess: true, exactOptionalPropertyTypes: true. It doesn't know that baseUrl is defined two levels up in your monorepo base config. So it:

• Suggests code that would fail noUncheckedIndexedAccess
• Gets confused about what @/ resolves to
• Doesn't know your target is ES2022, not ES5
• Gives wrong answers about module resolution

The TypeScript compiler API already resolves all of this. This MCP just exposes it.

🛠️ Tools

get_effective_compiler_options

Resolves the full extends chain and returns the merged compiler options that actually apply to a given tsconfig.json. Shows the inheritance chain, all merged options (with enums as readable strings, not magic numbers), and include/exclude patterns.

Effective TypeScript Configuration
  Config:            /project/apps/web/tsconfig.json
  Inheritance chain: /project/apps/web/tsconfig.json
                     → /project/tsconfig.base.json
                     → node_modules/@tsconfig/strictest/tsconfig.json

Compiler Options (merged):
  target: "ES2022"
  module: "NodeNext"
  moduleResolution: "NodeNext"
  strict: true
  noUncheckedIndexedAccess: true
  exactOptionalPropertyTypes: true
  baseUrl: "/project"
  paths: { "@/*": ["apps/web/src/*"] }

resolve_module_alias

Maps a TypeScript path alias (e.g. @/hooks/useAuth) to its physical file location on disk, using the resolved paths and baseUrl from the tsconfig. Returns all existing candidates with extension probing.

Alias Resolution: @/hooks/useAuth
  Config:   /project/apps/web/tsconfig.json
  Base URL: /project

Resolved physical paths:
  /project/apps/web/src/hooks/useAuth.ts      ✓ exists

analyze_project_references

Inspects the references array in a root tsconfig.json and validates that each referenced package has composite: true. Catches broken cross-package dependencies in TypeScript monorepos before they cause silent build failures.

Project References Analysis
  Config: /project/tsconfig.json
  References found: 2

  [✓] packages/shared → /project/packages/shared/tsconfig.json
  [✗ NOT FOUND] packages/deprecated → /project/packages/deprecated/tsconfig.json

Violations:
  ✗ packages/shared is referenced but does not have composite: true
    Fix: add "composite": true to packages/shared/tsconfig.json

🧪 What it looks like in practice

Agent is helping debug a TypeScript error and asks:

"What compiler options are actually active in this project?"

Without this MCP, the agent guesses based on what it sees in tsconfig.json. With it:

get_effective_compiler_options("/project/apps/web/tsconfig.json")
→ strict: true, noUncheckedIndexedAccess: true, target: "ES2022", module: "NodeNext"

Now the agent knows exactly why arr[0] has type string | undefined and not just string. No more wrong suggestions.

⚡ Setup

{
  "mcpServers": {
    "tsconfig-flattener": {
      "command": "npx",
      "args": ["-y", "tsconfig-inheritance-flattener-mcp"]
    }
  }
}

🚀 Usage

"What compiler options actually apply to /project/apps/web/tsconfig.json? It extends a monorepo base and @tsconfig/strictest."

"Where does @/components/Button resolve to on disk?"

"Are the project references in my root tsconfig valid? Do all referenced packages have composite: true?"

Works great alongside:

• ast-impact-mapper-mcp — for code→test correlation
• release-readiness-triage-mcp — for CI triage

📦 Links

• npm: npmjs.com/package/tsconfig-inheritance-flattener-mcp
• GitHub: github.com/vola-trebla/tsconfig-inheritance-flattener-mcp

License

MIT