http-load-profiler

A tool for sending increasing amounts of HTTP traffic to a web service and measuring response speed and errors. It reports p50, p90, and p99 latency, meaning the response time for typical, slower, and nearly slowest requests.

In plain words
What is it for?
Use it to load-test an API or website, find a practical concurrency limit, identify performance breakpoints, and choose a recommended traffic level.
Why use it?
It shows where a service starts slowing down, stops handling more traffic efficiently, or begins returning too many errors.

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/zebbern/claude-code-guide/http-load-profiler
Any agent
npx skills add zebbern/claude-code-guide --skill http-load-profiler
Clone the repo
git clone --depth 1 https://github.com/zebbern/claude-code-guide

Made for: Claude Code, Codex.

Per session 76 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,702 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 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 $0.00076 $0.01702
Opus 5 $0.00038 $0.00851
Sonnet 5 $0.00015 $0.00340
Haiku 4.5 $0.00008 $0.00170

Measured 2d ago against content hash ce4839afdba6, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade B, and why

http-load-profiler scanned grade B 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 2d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/http_benchmark.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

Asks for rootmediumPrivilege escalation

A mod that escalates privileges can change anything on the machine, not only the project.

sudo apt-get install wrk # recommended
skills/http-load-profiler/SKILL.md · 152 lines

How it starts

The opening of the file, as written. The whole thing — 152 lines — stays where its author put it; the contents beside it link to each section on GitHub.

HTTP Load Profiler — Stepped Concurrency Load Test + Inflection Point Analysis

Run stepped concurrency load tests against HTTP services, automatically collect latency percentiles, and detect performance inflection points.

Features

  • Dual engine support: Auto-detects wrk (preferred) or ab (Apache Bench); manual override available
  • Stepped concurrency: Ramps up through user-defined concurrency levels (default: 1 → 10 → 50 → 100 → 200 → 500)
  • Latency percentiles: Collects p50 / p90 / p99 latency at each level
  • Inflection point detection: Automatically identifies four types of performance inflection points
    • p99 latency accelerating (increase exceeds 2x the previous step's increase)
    • Throughput efficiency dropping significantly (RPS per connection drops > 40%)
    • Throughput saturated while latency spikes (RPS growth < 10%, p99 growth > 50%)
    • Error rate surging (exceeds 1% and doubles from previous step)
  • Optimal concurrency recommendation: Automatically suggests the best concurrency level based on inflection points
  • Zero Python dependencies: Pure standard library implementation

Quick Start

# Basic usage — run default stepped load test against target URL
python3 scripts/http_benchmark.py https://example.com/api/health

# Custom concurrency steps and duration per step
python3 scripts/http_benchmark.py https://example.com/api/health -s 5,20,50,100,300 -d 15

# Specify ab as the engine
python3 scripts/http_benchmark.py https://example.com/ -t ab

# JSON-only output (for programmatic parsing)
python3 scripts/http_benchmark.py https://example.com/api/health --json

# Use ab with a specific number of requests per step
python3 scripts/http_benchmark.py https://example.com/ -t ab -n 5000

# Save JSON report to a file
python3 scripts/http_benchmark.py https://example.com/api/health --json > report.json

Parameters

Parameter Short Default Description
url (required) Target URL (http:// or https://)
--steps -s 1,10,50,100,200,500 Concurrency steps (comma-separated positive integers)
--duration -d 10 Duration per step in seconds (used directly by wrk; ab estimates request count from this)
--requests -n concurrency×100 Total requests per step when using ab
--tool -t auto-detect Specify load testing tool: wrk or ab
--threads min(concurrency, CPU cores) Thread count for wrk
--json false Output JSON only

Read the full file on GitHub · 152 lines

Files

What ships with it

2 files 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. 2d ago First seen · 152 lines · 76 tokens per session scan B ce4839afdba6

Subscribe to this mod's changes

http-load-profiler is a skill published in the GitHub repository zebbern/claude-code-guide (4,597 stars, last pushed yesterday), licensed MIT. It adds 76 tokens to every session and 1,702 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it B with 1 finding (asks for root). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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