http-response-handling

http-response-handling is a skill for Claude Code, Codex from HKUDS/OpenSpace. It costs 21 tokens per session (1,057 once invoked), scanned A, original, MIT.

A method for downloading content from websites that use JavaScript to display their real pages. It uses browser-like request headers and checks whether the downloaded file contains actual content or only a loading placeholder.

In plain words
What is it for?
Use it when fetching JavaScript-dependent websites with curl, following redirects, inspecting saved responses, and checking their file type or contents.
Why use it?
Some websites return incomplete HTML to basic command-line requests, making their content appear missing. This helps identify and handle that response.

Skill for Claude CodeCodex

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 skills/hkuds/openspace/http-response-handling
Any agent
npx skills add HKUDS/OpenSpace --skill http-response-handling
Clone the repo
git clone --depth 1 https://github.com/HKUDS/OpenSpace

Made for: Claude Code, Codex.

Per session 21 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,057 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. 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 $0.00021 $0.01057
Opus 5 $0.00010 $0.00528
Sonnet 5 $0.00004 $0.00211
Haiku 4.5 $0.00002 $0.00106

Measured 3d ago against content hash 7b4457f257bc, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

http-response-handling scanned grade A with 1 finding 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

description: Handle websites requiring JavaScript by using curl with browser headers and validating file types.
benchmarks/gdpval/skills/http-response-handling/SKILL.md · 143 lines

How it starts

The opening of the file, as written. The whole thing — 143 lines — stays where its author put it; the contents beside it link to each section on GitHub.

HTTP Response Handling for JavaScript-Dependent Sites

When to Use This Skill

Use this technique when you need to fetch content from websites that:

  • Render content dynamically with JavaScript
  • Return placeholder HTML when accessed by non-browser clients
  • Deliver different content based on User-Agent headers

Core Technique

Step 1: Fetch Content with Browser-Like Headers

Use curl with a realistic User-Agent header to mimic a real browser:

curl -L -A "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36" -o output.html "https://example.com"

Key flags:

  • -L — Follow redirects
  • -A — Set User-Agent header to mimic a real browser
  • -o — Save output to file for inspection

Step 2: Detect Placeholder HTML Responses

After fetching, check if you received a placeholder response instead of actual content:

# Check file size (placeholder responses are often very small)
wc -c output.html

# Check for common placeholder indicators
grep -i "javascript" output.html | head -5
grep -i "loading" output.html | head -5
grep -i "noscript" output.html | head -5

Signs of a placeholder response:

  • File size is suspiciously small (<5KB for content pages)
  • Contains大量 JavaScript but minimal actual content
  • Has "loading", "spinner", or "noscript" tags
  • Missing expected text/data from the page

Step 3: Validate File Type Before Parsing

Before attempting format-specific parsing, validate the file type:

# Check the file type
file output.html

# Check the actual content type (if you have the headers)
curl -I -A "Mozilla/5.0 ..." "https://example.com" | grep -i content-type

# Inspect first few lines
head -50 output.html

Common checks:

  • HTML files: Should start with <!DOCTYPE or <html
  • JSON files: Should start with { or [
  • PDF files: Should start with %PDF
  • Empty/error pages: May contain error messages or generic HTML

Step 4: Handle Different Scenarios

Read the full file on GitHub · 143 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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 · 143 lines · 21 tokens per session scan A 7b4457f257bc

Subscribe to this mod's changes

http-response-handling is a skill published in the GitHub repository HKUDS/OpenSpace (7,486 stars, last pushed 21d ago), licensed MIT. It adds 21 tokens to every session and 1,057 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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