What Programming Languages Does Career-Ops Support and How to Switch Between Modes

TLDR: Career-Ops is built entirely in JavaScript/Node.js and supports multiple natural-language output modes—including German, French, Japanese, Arabic, and Chinese—by switching the language.modes_dir value in config/profile.yml.

Career-Ops is a Node.js automation pipeline designed for job search optimization. While the tool itself is written exclusively in JavaScript using ECMAScript modules (*.mjs), it offers extensive multi-language support for generating localized cover letters, CVs, and interview preparation materials. Understanding what programming languages Career-Ops supports versus how it handles natural language output is key to configuring your workflow.

Implementation Language: JavaScript and Node.js

According to the santifer/career-ops source code, the entire system is powered by JavaScript/Node.js and contains no compiled language runtimes. The core automation scripts—including scan.mjs for portal scanning and generate-pdf.mjs for PDF generation—are written as ECMAScript modules that execute on a modern V8 runtime. This architecture ensures cross-platform compatibility without requiring Go, Rust, or Python interpreters.

Key entry points in the repository include:

• scan.mjs – Entry point for portal scanning logic
• generate-pdf.mjs – PDF generation using Node.js and Playwright
• run.mjs – Executes specific evaluation modes
• auto-pipeline.mjs – Orchestrates the full automation workflow

Because the entire stack is JavaScript-based, you can inspect or modify any logic using standard Node.js debugging tools.

Supported Language Modes for Output Localization

Beyond its implementation language, Career-Ops provides language-specific modes that localize output for job searches in different natural languages. These modes are not separate programming languages but rather collections of localized markdown prompt files stored in modes/<lang>/ directories.

Supported language codes include:

• de – German
• fr – French
• ja – Japanese
• ar – Arabic
• zh – Chinese
• pt – Portuguese
• es – Spanish
• pl – Polish

Each mode directory contains a _shared.md file that overrides or extends the base English prompts with locale-specific phrasing, date formats, and BCP-47 language codes used by PDF and HTML templates.

How Language Modes Work Under the Hood

The Career-Ops engine uses a hierarchical prompt system to render localized content. As documented in AGENTS.md, the high-level language-mode selection logic relies on the language.modes_dir field in your configuration.

When processing a request, the core engine follows this flow:

1. The core JavaScript engine reads the language.modes_dir value from config/profile.yml
2. _shared.md in the target directory contains generic writing rules and language-agnostic placeholders
3. Language-specific sub-directories provide overrides for local conventions and formatting
4. The CLI or agent (such as Claude/Opencode) loads these prompts at runtime to generate localized output

This design means that switching from English to German does not require changing the underlying JavaScript code; only the prompt source directory changes.

How to Switch Between Language Modes

Switching the output language requires updating a single field in your user profile and notifying the agent. The recommended approach uses version-controlled configuration rather than runtime flags.

Step 1: Update the Profile Configuration

Edit config/profile.yml to point to your desired language directory:

# config/profile.yml

language:
  modes_dir: modes/de

Replace de with any supported two-letter code (fr, ja, ar, zh, etc.).

Step 2: Notify the Agent

When starting a new session, explicitly remind the agent to respect the configuration field:

Claude, please check `profile.yml` – I have set `language.modes_dir` to `modes/de`.

This step is necessary because the documentation treats this as a convention rather than an automatic schema enforcement.

Step 3: Execute the Mode

Run any standard command to generate localized output:

node run.mjs evaluate https://example.com/job

Or use the full pipeline:

node auto-pipeline.mjs https://jobs.example.com/role123

The engine will automatically load prompts from modes/de/ instead of the default English modes/ folder, affecting all downstream modes including pipeline, oferta, apply, and interview.

Programmatic Language Detection

If you are extending Career-Ops or building custom integrations, you can access the language mode programmatically by reading the profile configuration:

import { readFileSync } from 'fs';
import YAML from 'yaml';

const profile = YAML.parse(readFileSync('config/profile.yml', 'utf8'));
const modeDir = profile.language?.modes_dir ?? 'modes';
const shared = await import(`${modeDir}/_shared.md`);
// Use `shared` to build localized prompts

This pattern ensures your extensions respect the user's selected language mode without hardcoding paths.

Summary

• Career-Ops is implemented entirely in JavaScript/Node.js using ECMAScript modules (*.mjs), with no dependencies on compiled languages.
• The repository supports natural-language output modes for German, French, Japanese, Arabic, Chinese, Portuguese, Spanish, Polish, and others via the modes/<lang>/ directory structure.
• Switching languages requires setting language.modes_dir in config/profile.yml and reminding the agent to check this field at the start of each session.
• All modes rely on a hierarchical prompt system using _shared.md files to maintain consistent formatting while allowing locale-specific customization.

Frequently Asked Questions

Is Career-Ops written in Python or JavaScript?

Career-Ops is written entirely in JavaScript and runs on Node.js. The repository contains no Python, Go, or Rust code; all core functionality—including the scanner, evaluator, and PDF generator—resides in .mjs files like scan.mjs and generate-pdf.mjs.

Can I add a custom language mode to Career-Ops?

Yes. Create a new directory under modes/ using a standard two-letter language code (e.g., modes/it/ for Italian), add a _shared.md file with your localized prompts, and set language.modes_dir: modes/it in config/profile.yml. The engine will automatically load your custom mode as long as the directory structure matches existing modes.

Do I need to restart the agent after changing the language mode?

You do not need to restart the agent, but you must remind it once per session to check config/profile.yml for the language.modes_dir setting. The system relies on this convention rather than automatic schema validation, so explicitly stating "check my profile, I set language.modes_dir to modes/fr" ensures the agent loads the correct prompts.

What is the difference between the implementation language and language modes in Career-Ops?

The implementation language is JavaScript, which powers the automation engine and CLI. Language modes refer to the natural-language localization of output content (cover letters, CVs) stored in modes/<lang>/ directories. You can run the JavaScript engine in English while generating job application materials in Japanese, German, or Arabic by switching the mode configuration.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
      "args": ["-y", "instagit@latest"]
    }
  }
}