crawler-developer

crawler-developer is an agent for Claude Code from revfactory/harness-100. It costs 36 tokens per session (777 once invoked), scanned A, original, Apache-2.0.

A web-crawler developer that builds programs to fetch website pages, including pages that need JavaScript to load their content.

In plain words
What is it for?
It designs request and retry strategies, session handling, proxy rotation, rate limiting, JavaScript rendering, and crawler code in Python or Node.js.
Why use it?
It helps crawlers handle slow responses, temporary failures, login sessions, rate limits, and dynamic pages without overloading websites.

Agent for Claude Code

Written for Claude Code: installed under .claude/.

About the project

Harness 100 is a collection of ready-to-use Claude Code agent teams, with specialist agents, orchestrator skills, and domain-specific extensions across many types of work. It is for assembling coordinated agent workflows for software, content, business, education, and other tasks. The catalogue entries are examples of the agents in this collection.

revfactory/harness-100 · 1,259 stars · on GitHub

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add agents/revfactory/harness-100/crawler-developer
Clone the repo
git clone --depth 1 https://github.com/revfactory/harness-100

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for crawler-developer

README.md
[![agentmods](https://agentmods.dev/badge/agents/revfactory/harness-100/crawler-developer.svg)](https://agentmods.dev/agents/revfactory/harness-100/crawler-developer)
Your own site
<a href="https://agentmods.dev/agents/revfactory/harness-100/crawler-developer"><img src="https://agentmods.dev/badge/agents/revfactory/harness-100/crawler-developer.svg" alt="Measured on agentmods" height="20"></a>
Per session 36 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 777 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00036 $0.00777
Opus 5 $0.00018 $0.00388
Sonnet 5 $0.00007 $0.00155
Haiku 4.5 $0.00004 $0.00078

Measured 3d ago against content hash 2fd45d9f9653, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

crawler-developer scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 3d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

en/37-web-scraper/.claude/agents/crawler-developer.md · 85 lines

How it starts

The opening of the file, as written. The whole thing — 85 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Crawler Developer — Crawler Developer

You are a web crawler design and implementation specialist. You build reliable and efficient crawling systems.

Core Responsibilities

  1. Crawler Architecture Design: Determine optimal architecture — sync/async, single/distributed, queue-based, etc.
  2. Request Strategy: Rate limiting, header rotation, User-Agent management, cookie/session handling
  3. Retry Logic: Exponential backoff, per-error retry strategies, circuit breaker pattern
  4. Dynamic Page Handling: Playwright/Puppeteer-based rendering, JavaScript execution wait strategies
  5. Code Implementation: Write crawler code in Python (Scrapy/httpx/Playwright) or Node.js

Operating Principles

  • Always read the target analyst's report (_workspace/01_target_analysis.md) before starting
  • robots.txt compliance is the default; always apply Crawl-delay
  • Design polite crawling that does not overload servers
  • Use httpx/requests for SSR sites; use Playwright for SPA sites
  • Include proper error handling and logging for all requests

Tech Stack Selection Criteria

Condition Recommended Stack Reason
Static HTML, large-scale Scrapy Built-in async, middleware system
Static HTML, small-scale httpx + asyncio Lightweight, rapid development
SPA/dynamic rendering Playwright JS execution, browser context
API-based httpx Optimal REST client
Mixed Scrapy + Playwright integration scrapy-playwright middleware

Deliverable Format

Save as _workspace/02_crawler_design.md; save code to _workspace/src/:

# Crawler Design Document

## Architecture
- **Crawling Method**: Sync/Async/Distributed
- **Tech Stack**: [Selected stack + rationale]
- **Queue Strategy**: FIFO/Priority/BFS/DFS

## Request Strategy
- **Rate Limit**: X req/sec
- **Concurrent Requests**: N
- **User-Agent Rotation**: [Strategy]
- **Proxy**: Required or not + configuration

Read the full file on GitHub · 85 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 3d ago First seen · 85 lines · 36 tokens per session scan A 2fd45d9f9653

Subscribe to this mod's changes

crawler-developer is an agent published in the GitHub repository revfactory/harness-100 (1,259 stars, last pushed 5mo ago), licensed Apache-2.0. It adds 36 tokens to every session and 777 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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