Web Fetch Strategy

Web Fetch Strategy

Common web fetching strategy for anti-crawler handling.

Site Classification

Type	Examples	Characteristics
Anti-crawler	Reddit, Twitter/X, LinkedIn	Need login or browser fingerprint
Regular	blog.rust-lang.org, docs.rs	No anti-crawler, direct fetch

Fetch Priority

Anti-crawler sites: Local Chrome → crawl4ai MCP → give up and mark
Regular sites: WebFetch → crawl4ai MCP

Tools

1. Local Chrome (for anti-crawler)

User's real browser with login and normal fingerprint.

macOS:

# Open URL
osascript -e 'tell application "Google Chrome" to open location "URL"'

# Get page HTML
osascript -e 'tell application "Google Chrome" to execute front window'\''s active tab javascript "document.documentElement.outerHTML"'

2. crawl4ai MCP (fallback)

Strong anti-crawler bypass, needs Docker.

mcp__crawl4ai__scrape(url: "URL")

3. WebFetch (regular sites)

Built-in tool, simple and fast, no anti-crawler capability.

Site Routing

Domain	Tool	Reason
reddit.com	Local Chrome	Strict anti-crawler
twitter.com / x.com	Local Chrome	Needs login
linkedin.com	Local Chrome	Strict anti-crawler
*.rust-lang.org	WebFetch	No anti-crawler
docs.rs	WebFetch	No anti-crawler
crates.io	WebFetch	No anti-crawler
this-week-in-rust.org	WebFetch	No anti-crawler
rustfoundation.org	WebFetch	No anti-crawler
github.com	WebFetch	Light rate limit

Failure Handling

1. Local Chrome fails → try crawl4ai
2. crawl4ai fails → try WebFetch
3. All fail → mark "Fetch failed: {reason}"

Validation

After fetch, check:

• Content is not empty
• Not an error page (403, 429, "blocked")
• Contains expected data