Backend API

What it does

When your agent uses it

• Working on packages/backend/ code
• Adding RPC methods to BootcAPI
• Implementing container/image operations
• Asking about backend patterns

Example prompts

• “Use the backend-api skill to guide backend development with @podman-desktop/api and the bootc extension's RPC system”
• “/backend-api”

Requirements

• Node.js

Workflow steps

5 steps, taken from the first numbered list in SKILL.md.

1. 1Full API types: Read node_modules/@podman-desktop/api/index.d.ts
2. 2Current RPC contract: Read packages/shared/src/BootcAPI.ts
3. 3Current models: Read files in packages/shared/src/models/
4. 4Current messages: Read packages/shared/src/messages/Messages.ts
5. 5See existing usage: grep -r "extensionApi." packages/backend/src/

What it can do on your machine

Read from SKILL.md and the folder at commit 4230bcf. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  No scripts in the folder and no shell commands in SKILL.md (its code samples are typescript and bash).

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  No URLs in SKILL.md.

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Backend API loads about 1k tokens when it runs. Until then it costs about 97 tokens; SKILL.md has 261 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~97

When it runs · the whole SKILL.md, loaded when a task matches

~1k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from podman-desktop/extension-bootc at commit 4230bcf, republished under its Apache-2.0 licence (© podman-desktop). 261 words, ~1,008 tokens.

name

backend-api

description

Guides backend development with @podman-desktop/api and the bootc extension's RPC system. Covers container engine operations, provider management, RPC communication, build orchestration, VM management, and configuration. Triggers when working on packages/backend/ code, adding RPC methods to BootcAPI, implementing container/image operations, or asking about backend patterns.

paths

packages/backend/src/**/*.ts, packages/shared/src/**/*.ts

import * as extensionApi from '@podman-desktop/api';

export abstract class BootcApi {
  // ... existing methods
  abstract myNewMethod(param: string): Promise<ResultType>;
}

export class BootcApiImpl extends BootcApi {
  async myNewMethod(param: string): Promise<ResultType> {
    const result = await extensionApi.containerEngine.listImages();
    return transformResult(result);
  }
}

import { bootcClient } from '/@/api/client';
const result = await bootcClient.myNewMethod('value');

cat packages/shared/src/messages/NoTimeoutChannels.ts

cat packages/shared/src/messages/Messages.ts

this.panel.webview.postMessage({ id: Messages.MSG_HISTORY_UPDATE, body: data });

import { rpcBrowser } from '/@/api/client';
rpcBrowser.subscribe(Messages.MSG_NAVIGATE_BUILD, (path: string) => {
  router.goto(`/disk-images/build/${path}`);
});

# Full API surface — the single source of truth
cat node_modules/@podman-desktop/api/index.d.ts

# Find how specific APIs are already used in this codebase
grep -rn "extensionApi\.\(containerEngine\|window\|provider\|navigation\|configuration\|process\|env\)" packages/backend/src/

# Key backend modules — read these to find available helpers
ls packages/backend/src/*.ts
ls packages/shared/src/models/

© podman-desktop, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

Just SKILL.md in .agents/skills/backend-api of podman-desktop/extension-bootc.

Open the folder on GitHubat commit 4230bcf