# Crawlberg > >- Crawl, scrape, and convert websites to Markdown using the local crawlberg CLI and its MCP server. Use when the user wants to fetch a page, follow links across a domain, enumerate URLs, or drive a real browser. Covers installation, the subcommands (scrape, crawl, map, interact, batch-scrape, batch-crawl, download, citations, version, mcp, serve), output formats (JSON + Markdown), browser fallback, and when to prefer the MCP server over shelling out. - Skill: `thedixitjain/crawlberg` (Agent Skill) - Install (CLI): `npx skillmds add thedixitjain/crawlberg` - Raw SKILL.md: https://api.skillmd.com/api/skills/thedixitjain/crawlberg/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: AI & ML - Author: thedixitjain (https://skillmd.com/u/thedixitjain) - Updated: 2026-09-09 - Page: https://skillmd.com/skills/thedixitjain/crawlberg --- # Crawlberg Crawlberg is a Rust-native web crawler and scraper. It fetches static HTML with `reqwest`, falls back to headless Chrome when a page needs JS or trips a WAF, and converts every result to clean Markdown via the built-in HTML→Markdown engine. Use this skill when the user wants to: - Scrape a single URL to Markdown plus structured metadata. - Crawl a site following links bounded by depth, page count, and concurrency. - Enumerate URLs from sitemaps without paying for rendering. - Drive a real browser (click, type, scroll) and capture the resulting DOM. - Run the same operations from another agent harness via MCP tools. ## Installation The plugin shells out to a `crawlberg` binary on `PATH`. Install one of: ```bash brew install xberg-io/tap/crawlberg # or run without a persistent install (the CLI proxy package self-installs the binary): npx @xberg-io/crawlberg-cli --help uvx --from crawlberg-cli crawlberg --help # or build from source: cargo install crawlberg-cli --features all ``` The `serve` and `mcp` subcommands are gated behind non-default cargo features (`api` and `mcp`). The Homebrew tap is built with all features, so both subcommands work out of the box. A from-source build must pass `--features mcp` (and `--features api` for `serve`), or `--features all`, to include them. Verify: ```bash crawlberg --version ``` Headless fallback needs Chrome/Chromium reachable locally (`chromiumoxide` launches it on demand). Skip the install if you only plan to use `--browser-mode never`. ## Command map ```text crawlberg scrape # single page → JSON or Markdown crawlberg crawl # follow links, BFS, depth-bounded crawlberg map # enumerate URLs via sitemaps + link extraction crawlberg interact # browser actions: click, type, scroll crawlberg batch-scrape # scrape many URLs concurrently crawlberg batch-crawl # crawl many seed URLs concurrently crawlberg download # download a document, report file metadata crawlberg citations # markdown links → numbered citations (text or @file.md) crawlberg version # print the crawlberg version as JSON crawlberg mcp # MCP server (stdio) — auto-registered (`mcp` feature) crawlberg serve # REST API server (`api` feature) ``` `crawl` also handles batching implicitly: pass multiple seed URLs and it fans out via `batch_crawl` internally. The explicit `batch-scrape` and `batch-crawl` subcommands expose the same concurrency for many independent URLs. Per-subcommand flags: | Subcommand | Positional | Key flags | | -------------- | ----------------- | ------------------------------------------------------------------------------------------------------------- | | `scrape` | `` | `--proxy`, `--user-agent` (plus shared flags below) | | `crawl` | `` | `--depth`/`-d` (2), `--max-pages`/`-n`, `--concurrent`/`-c` (10), `--rate-limit` (200), `--stay-on-domain`, `--proxy`, `--user-agent` | | `map` | `` | `--limit`, `--search` | | `interact` | `` | `--actions ` (required) | | `batch-scrape` | `` | `--concurrent`/`-c` (10), `--proxy`, `--user-agent` | | `batch-crawl` | `` | `--depth`/`-d` (2), `--max-pages`/`-n`, `--concurrent`/`-c` (10), `--rate-limit` (200), `--stay-on-domain`, `--proxy`, `--user-agent` | | `download` | `` | `--max-size` | | `citations` | `` | none (input is markdown text or `@file.md`) | | `version` | — | none | | `serve` | — | `--host` (0.0.0.0), `--port` (3000) | | `mcp` | — | none (stdio transport) | ### Shared flags | Flag | Default | Notes | | ----------------------- | -------- | -------------------------------------------------- | | `--format` | `json` | `json` or `markdown`. | | `--timeout` | `30000` | Request timeout in milliseconds. | | `--browser-mode` | `auto` | `auto`, `always`, or `never`. | | `--browser-endpoint` | — | Optional CDP `ws://` or `wss://` URL. | | `--respect-robots-txt` | off | Pass to obey `robots.txt`. | | `--config ` | — | Inline JSON or `@file.json` to override defaults. | The `--config` flag accepts the full `CrawlConfig` schema. Anything you set explicitly on the CLI overrides the corresponding JSON field. These shared flags apply to the crawl/scrape-family subcommands. `--format`, `--browser-mode`, `--browser-endpoint`, and `--config` cover `scrape`, `crawl`, `map`, `interact`, `batch-scrape`, and `batch-crawl`; `download` takes `--timeout`, `--browser-mode`, `--browser-endpoint`, `--max-size`, and `--config` (no `--format`). `--respect-robots-txt` applies to `scrape`, `crawl`, `map`, `batch-scrape`, and `batch-crawl`. `citations` and `version` take no shared flags. ## Scrape a single page ```bash crawlberg scrape https://example.com --format markdown ``` JSON output (default) carries the rendered Markdown, page metadata (`PageMetadata`), links by category, images, feeds, JSON-LD blocks, and HTTP response metadata. Use Markdown output when piping into a file the user will read. See the `scraping-html-to-markdown` skill for the full flag surface. ## Crawl a site ```bash crawlberg crawl https://example.com \ --depth 3 --max-pages 200 --concurrent 8 --rate-limit 250 \ --stay-on-domain --respect-robots-txt --format markdown ``` Crawling is BFS by default, bounded by `--depth`, `--max-pages`, and `--concurrent`. Per-domain politeness is enforced by `--rate-limit` (milliseconds between requests to the same origin). See the `crawling-a-site` skill for the recommended defaults and the full flag surface. ## Map URLs ```bash crawlberg map https://example.com --limit 500 --search docs --format markdown ``` `map` reads `sitemap.xml` (and nested sitemaps), then falls back to link extraction from the seed page. It does not render pages — use it to plan a crawl or to feed URLs into another tool. ## Browser interaction ```bash crawlberg interact https://example.com \ --actions '[{"type":"click","selector":"#load-more"}, {"type":"wait","milliseconds":500}, {"type":"scrape"}]' ``` Action types are `click`, `type`, `press`, `scroll`, `wait`, `screenshot`, `executeJs`, and `scrape` (to wait for an element, use `wait` with a `selector` field). The result wraps the final HTML under `interaction.final_html`. See the `automating-the-browser` skill for the full action schema and limits. ## MCP server When this plugin is installed in a Claude Code / Codex / Cursor / Gemini / opencode harness, the MCP server is auto-registered: ```text crawlberg mcp ``` `mcp` is a stdio-transport server and takes no arguments. It requires a binary built with the `mcp` feature (see Installation). The server registers nine tools (the same set is served over the Streamable HTTP transport when running `crawlberg serve`): | Tool | Purpose | Parameters | | -------------------- | --------------------------------------------------------------- | ------------------------------------------------------------------------------------------ | | `scrape` | Scrape one URL to Markdown or JSON (content, metadata, links). | `url` (required), `format` (`markdown`\|`json`), `use_browser` (bool — force browser) | | `crawl` | Follow links from a URL, bounded by depth/page count. | `url` (required), `max_depth`, `max_pages`, `format`, `stay_on_domain` | | `map` | Discover all URLs via links and sitemaps. | `url` (required), `limit`, `search`, `respect_robots_txt` | | `batch_scrape` | Scrape multiple URLs concurrently. | `urls` (required array), `format`, `concurrency` | | `batch_crawl` | Crawl multiple seed URLs concurrently. | `urls` (required array), `max_depth`, `max_pages`, `format`, `stay_on_domain`, `concurrency` | | `download` | Download a document and return file metadata. | `url` (required), `max_size` | | `interact` | Execute browser actions on a page (mutating/destructive). | `url` (required), `actions` (required array of action objects) | | `generate_citations` | Rewrite markdown links as numbered citations + reference list. | `markdown` (required) | | `get_version` | Return the crawlberg library version. | none | Prefer MCP tools over shelling out when both are available: - Typed schemas surface argument errors before the call. - Results stream back as structured tool output instead of stdout text. - No `--format` juggling — the harness pulls whatever shape it needs. Fall back to the CLI when you need to script a pipeline, capture stderr, or chain with shell tools. ## Headless fallback In `--browser-mode auto` (default), the engine: 1. Fetches statically via `reqwest`. 2. Detects WAF blocks (8 vendors) and JS-only shells. 3. Re-fetches through headless Chrome with a real fingerprint when needed. Force the browser path with `--browser-mode always` when you already know the page needs JS. Use `--browser-mode never` for hot loops where the cost of a stray Chrome launch is unacceptable. Point `--browser-endpoint ws://host:9222/devtools/browser/` at an already-running Chrome to skip the local launch. See the `headless-fallback` skill for symptoms, costs, and external-CDP patterns. ## Output formats | Mode | Use when | | ---------- | ------------------------------------------------------- | | `json` | Downstream consumer needs metadata, links, images, etc. | | `markdown` | Human reader or LLM-context payload. | Markdown output skips metadata. If you need both, run with `--format json` and read `result.markdown.content`. ## Robots, rate limits, ethics - `--respect-robots-txt` is off by default; pass it for any crawl on a host you do not own. - The default `--rate-limit 200` already produces a polite cadence; raise it for shared hosts. - Identify the crawler honestly via `--user-agent`. Do not impersonate a browser unless the operator has approved it. ## Cross-references - `skills/crawling-a-site/SKILL.md` — multi-page crawl with depth, page caps, concurrency, rate limits, and domain scoping. - `skills/scraping-html-to-markdown/SKILL.md` — single-page rendering, the Markdown output shape, and common pitfalls. - `skills/mapping-urls/SKILL.md` — `map`: sitemap + link URL discovery, filtering, and seeding a crawl. - `skills/automating-the-browser/SKILL.md` — `interact`: the full scripted action schema, limits, and result shape. - `skills/serving-the-api/SKILL.md` — `serve`: the Firecrawl-v1-compatible REST API server and its endpoints. - `skills/headless-fallback/SKILL.md` — when and how to force the browser backend. --- **Source:** [`hashgraph-online/awesome-codex-plugins`](https://github.com/hashgraph-online/awesome-codex-plugins) → `plugins/kreuzberg-dev/plugins/plugins/crawlberg/skills/crawlberg/SKILL.md`