# Type generation

How protocol specs become TypeScript types, typings tests, and API docs. Agents: do not hand-edit generated files — change the source in this chart and regenerate.

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## What to edit[​](#what-to-edit "Direct link to What to edit")

| You want to change                          | Edit this                                                                     | Then run                                                                    |
| ------------------------------------------- | ----------------------------------------------------------------------------- | --------------------------------------------------------------------------- |
| A WebDriver / Appium / vendor command shape | `packages/wdio-protocols/src/protocols/*.ts`                                  | `pnpm run compile:all` and `pnpm run test:typings:webdriver`                |
| A user-facing `browser.*` / `$().*` command | `packages/webdriverio/src/commands/**` plus its unit test and typings snippet | `pnpm run test:package webdriverio` and `pnpm run test:typings:webdriverio` |
| BiDi types                                  | `infra/bidiCodegen/`                                                          | `pnpm run generate:bidi`                                                    |
| Command API docs text                       | JSDoc on the webdriverio command                                              | `pnpm run docs:generate`                                                    |
| Protocol API docs text                      | the protocol spec `description` / `ref`                                       | `pnpm run docs:generate`                                                    |

See also [High level overview](/docs/flowcharts/highleveloverview.md). Protocol specs are owned by `packages/wdio-protocols`; the compiler plugin lives in `infra/compiler/src/type-generation`.