multi-url-environment-reference-custom-commands

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How to author custom commands for the multi-url-environment-reference CLI using the co-generated SDK.

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

name: multi-url-environment-reference-custom-commands description: How to author custom commands for the multi-url-environment-reference CLI using the co-generated SDK.

Custom Commands for multi-url-environment-reference

Overview

The multi-url-environment-reference 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/multi-url-environment-reference/custom.rs    ← Your command handlers (protected by .fernignore)
cli/multi-url-environment-reference/sdk_glue.rs  ← Generated bridge: sdk_client() + block_on()
cli/multi-url-environment-reference/main.rs      ← Generated entrypoint (calls custom::register)
multi-url-environment-reference-sdk/             ← Co-generated typed SDK crate
multi-url-environment-reference-types/           ← Co-generated typed model crate

Adding a Custom Command

1. Edit cli/multi-url-environment-reference/custom.rs

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

use multi_url_environment_reference_sdk::api::*;

pub fn register(app: CliApp) -> CliApp {
    let app = app.command(
        clap::Command::new("list-items")
            .about("Run items list-items")
        ,
        |matches, ctx| {
            let client = super::sdk_glue::sdk_client(ctx);
            let result = super::sdk_glue::block_on(
                client.items.list_items(),
            )?;
            println!("{}", serde_json::to_string_pretty(&result).unwrap());
            Ok(())
        },
    );
    app
}

Then build and test:

cargo build
multi-url-environment-reference list-items

2. Available SDK Clients

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

Field Type Description
client.items multi_url_environment_reference_sdk::api::ItemsClient items operations
client.auth multi_url_environment_reference_sdk::api::AuthClient auth operations
client.files multi_url_environment_reference_sdk::api::FilesClient files 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 multi_url_environment_reference_sdk::api::*;

4. Authentication

Custom commands automatically inherit the CLI's authentication. The following auth schemes are configured:

  • BearerAuth (bearer): env MULTI_URL_ENVIRONMENT_REFERENCE_TOKEN

No manual auth wiring is needed in custom command handlers.

Regeneration Safety

File Regenerated? Notes
cli/multi-url-environment-reference/custom.rs No Protected by .fernignore
cli/multi-url-environment-reference/sdk_glue.rs Yes Bridges AppContext → SDK client
cli/multi-url-environment-reference/main.rs Yes Calls custom::register(app)
multi-url-environment-reference-sdk/ Yes Co-generated typed SDK crate
multi-url-environment-reference-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
multi-url-environment-reference <your-command> [args]

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