api-wide-base-path-with-default-custom-commands

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How to author custom commands for the api-wide-base-path-with-default CLI using the co-generated SDK.

fern-api By fern-api schedule Updated 6/8/2026

name: api-wide-base-path-with-default-custom-commands description: How to author custom commands for the api-wide-base-path-with-default CLI using the co-generated SDK.

Custom Commands for api-wide-base-path-with-default

Overview

The api-wide-base-path-with-default CLI supports user-authored custom commands that are compiled into the binary alongside the auto-generated API commands. Custom commands get a fully-wired SDK client that inherits the CLI's auth, retries, TLS, base URL, and global headers — zero configuration required.

Architecture

cli/api-wide-base-path-with-default/custom.rs    ← Your command handlers (protected by .fernignore)
cli/api-wide-base-path-with-default/sdk_glue.rs  ← Generated bridge: sdk_client() + block_on()
cli/api-wide-base-path-with-default/main.rs      ← Generated entrypoint (calls custom::register)
api-wide-base-path-with-default-sdk/             ← Co-generated typed SDK crate
api-wide-base-path-with-default-types/           ← Co-generated typed model crate

Adding a Custom Command

1. Edit cli/api-wide-base-path-with-default/custom.rs

This file is protected by .fernignorefern generate will never overwrite it. Register commands in the register() function:

use api_wide_base_path_with_default_sdk::api::*;

pub fn register(app: CliApp) -> CliApp {
    let app = app.command(
        clap::Command::new("widgets-create")
            .about("Run widgets widgets-create")
            .arg(clap::Arg::new("apiVersion").required(true))
        ,
        |matches, ctx| {
            let api_version = matches.get_one::<String>("apiVersion").unwrap();
            let client = super::sdk_glue::sdk_client(ctx);
            let result = super::sdk_glue::block_on(
                client.widgets.widgets_create(api_version),
            )?;
            println!("{}", serde_json::to_string_pretty(&result).unwrap());
            Ok(())
        },
    );
    app
}

Then build and test:

cargo build
api-wide-base-path-with-default widgets-create <apiVersion>

2. Available SDK Clients

The sdk_glue::sdk_client(ctx) call returns a api_wide_base_path_with_default_sdk::api::Client with the following sub-clients:

Field Type Description
client.widgets api_wide_base_path_with_default_sdk::api::WidgetsClient widgets operations

3. Key Patterns

Get the SDK client (execution-sharing, fully authenticated):

let client = super::sdk_glue::sdk_client(ctx);

Run an async SDK call from a sync handler:

let result = super::sdk_glue::block_on(
    client.some_resource.some_method(args),
)?;

Use typed models for request/response serialization:

use api_wide_base_path_with_default_sdk::api::*;

Regeneration Safety

File Regenerated? Notes
cli/api-wide-base-path-with-default/custom.rs No Protected by .fernignore
cli/api-wide-base-path-with-default/sdk_glue.rs Yes Bridges AppContext → SDK client
cli/api-wide-base-path-with-default/main.rs Yes Calls custom::register(app)
api-wide-base-path-with-default-sdk/ Yes Co-generated typed SDK crate
api-wide-base-path-with-default-types/ Yes Co-generated typed models

After running fern generate, your custom.rs is preserved. All generated code (SDK, types, glue, main.rs) is updated to match the latest API spec. If the SDK surface changes (renamed methods, new sub-clients), update your custom.rs to match.

Build & Test

# Build the CLI (includes custom commands)
cargo build

# Run your custom command
api-wide-base-path-with-default <your-command> [args]

# Run with verbose output for debugging
RUST_LOG=debug api-wide-base-path-with-default <your-command> [args]
Install via CLI
npx skills add https://github.com/fern-api/fern --skill api-wide-base-path-with-default-custom-commands
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