HTTP Load Profiler

What it does

When your agent uses it

• Tasks that involve Load testing
• Tasks that involve Performance optimization
• Tasks that involve Site reliability engineering

Example prompts

• “load test this URL”
• “benchmark my API”
• “find the max concurrency”
• “/http-load-profiler”

Requirements

• Python 3

Workflow steps

4 steps, taken from the first numbered list in SKILL.md.

1. 1p99 latency acceleration: Triggers when the current p99 increase exceeds 2x the previous step's increase
2. 2Throughput efficiency: Triggers when RPS per connection drops > 40% from the previous step
3. 3Saturation detection: Triggers when RPS growth < 10% while p99 growth > 50%
4. 4Error rate: Triggers when rate exceeds 1% and doubles from the previous step

What it can do on your machine

Read from SKILL.md and the folder at commit 4698e3b. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  Ships 1 file in scripts/ (Python), which the agent can run.

  Shell commands in SKILL.md call:

  • python3
  • apt-get
  • brew

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  No URLs in SKILL.md.

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

HTTP Load Profiler loads about 1.6k tokens when it runs. Until then it costs about 90 tokens; SKILL.md has 386 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~90

When it runs · the whole SKILL.md, loaded when a task matches

~1.6k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

• NoteRuns commands with sudoSKILL.md:127

  sudo apt-get install wrk          # recommended

• NoteRuns commands with sudoSKILL.md:128

  sudo apt-get install apache2-utils # ab

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); the scripts in this folder are not scanned.

SKILL.md

The full file from zebbern/claude-code-guide at commit 4698e3b, republished under its MIT licence (© zebbern). 386 words, ~1,554 tokens.

name

http-load-profiler

description

Run stepped HTTP load tests with ab/wrk, ramping concurrency levels to collect p50/p90/p99 latency, detect performance inflection points, and recommend optimal concurrency. Triggered by requests like 'load test this URL', 'benchmark my API', 'find the max concurrency', or mentions of p99 latency, throughput saturation, or capacity planning.

license

MIT

type

tool

tags

http, benchmark, performance, latency, load-testing

# 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

Tool: wrk
Target URL: https://example.com/api/health
Concurrency steps: [1, 10, 50, 100, 200, 500]
Duration per step: 10s

----------------------------------------------------------------------------------
  Conc. |        RPS |  Avg(ms) |  P50(ms) |  P90(ms) |  P99(ms) |   Errors | Inflection
----------------------------------------------------------------------------------
     1 |      245.3 |      4.1 |      3.8 |      5.2 |      8.1 |   0.00% |
    10 |     2301.5 |      4.3 |      4.0 |      5.8 |      9.3 |   0.00% |
    50 |     9876.2 |      5.1 |      4.6 |      7.2 |     12.5 |   0.00% |
   100 |    14523.1 |      6.9 |      5.8 |     10.3 |     22.7 |   0.00% |
   200 |    15102.3 |     13.2 |     10.1 |     22.5 |     58.3 |   0.12% |  ◀
   500 |    14890.5 |     33.6 |     28.3 |     55.2 |    132.1 |   1.35% |  ◀
----------------------------------------------------------------------------------

Inflection point analysis:
  ▶ Concurrency 200:
    - p99 latency accelerating: 22.7ms → 58.3ms (increase 35.6ms, previous step increase 10.2ms)
    - Throughput saturated with latency spike: RPS grew only 3.9% while p99 latency grew 156.8%
  ▶ Concurrency 500:
    - Error rate surging: 0.12% → 1.35%

Recommended optimal concurrency: 100

{
  "url": "https://example.com/api/health",
  "tool": "wrk",
  "duration_per_step": 10,
  "steps": [
    {
      "concurrency": 1,
      "rps": 245.3,
      "avg_latency_ms": 4.1,
      "p50_ms": 3.8,
      "p90_ms": 5.2,
      "p99_ms": 8.1,
      "total_requests": 2453,
      "errors": 0
    }
  ],
  "inflection_points": [
    {
      "concurrency": 200,
      "step_index": 4,
      "reasons": ["p99 latency accelerating: ..."]
    }
  ],
  "recommended_concurrency": 100
}

# Ubuntu / Debian
sudo apt-get install wrk          # recommended
sudo apt-get install apache2-utils # ab

# macOS
brew install wrk
# ab is pre-installed on macOS

© zebbern, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 2 other files (scripts) in skills/http-load-profiler of zebbern/claude-code-guide.

• SKILL.md
• LICENSE
• scripts/http_benchmark.py

Open the folder on GitHubat commit 4698e3b