performance-testing

A procedure for testing the performance of local web or gRPC services with k6, a tool that generates simulated requests and measures responses.

In plain words
What is it for?
Use it for local load, stress, spike, soak, scalability, latency, or throughput tests of REST, HTTP, gRPC, or representative applications.
Why use it?
It restricts tests to safe local targets, avoids changing business data, and requires an approved test plan and user-provided performance goals.

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/felipepg22/fpgskills/performance-testing
Any agent
npx skills add felipepg22/FPGSkills --skill performance-testing
Clone the repo
git clone --depth 1 https://github.com/felipepg22/FPGSkills

Made for: Claude Code, Codex.

Per session 97 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 856 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 $0.00097 $0.00856
Opus 5 $0.00048 $0.00428
Sonnet 5 $0.00019 $0.00171
Haiku 4.5 $0.00010 $0.00086

Measured 2d ago against content hash 1431dfff6040, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

performance-testing 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 2d ago.

The scan reads SKILL.md. This mod also ships 24 executable files (assets/k6/grpc-stream.js, assets/k6/grpc-unary.js, assets/k6/http-endpoint.js, …), 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.

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.

skills/performance-testing/SKILL.md · 34 lines

How it starts

The opening of the file, as written. The whole thing — 34 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Performance Testing

Produce evidence-backed local performance tests without inventing traffic, SLOs, safety, or causality.

Enforce the contract

  • Run only against loopback addresses or repository-proven services on the local container network. Inspect effective application configuration and refuse execution when writable remote dependencies exist or cannot be ruled out.
  • Exclude every operation or journey that mutates business data. Authentication may create an expiring local session when it uses a test identity and does not mutate business data.
  • Generate and structurally validate the executable tests first. Hash them into the complete test plan, compute the plan fingerprint, and execute only after the user explicitly approves that fingerprint. Recompute and request approval after any material plan or executable change.
  • Prefer execution in sub-agents so raw output does not consume the coordinating context. Use the parent agent only when delegation is unavailable.
  • Use only user-supplied SLOs from the conversation. Without one, report a baseline and no pass/fail verdict.
  • Keep secrets in environment-variable references. Never place secret values in plans, prompts, tests, logs, or reports.
  • Do not install k6, container runtimes, exporters, or reporting services automatically.

Run the workflow

  1. Read references/discovery.md completely. Inspect the repository, infer supported cases, and ask one compact intake round containing only decisions not already answered.
  2. Read references/plan-and-safety.md, references/plan-schema.md, references/workloads.md, references/execution.md, references/reporting.md, and references/run-schema.md completely. Read references/rest.md for REST/HTTP or references/grpc.md for gRPC.
  3. Copy the closest template from assets/k6/, adapt it to repository evidence, and structurally validate every generated executable. Keep generated files under docs/performance-tests/ unless the repository already has an approved convention.
  4. Create the canonical plan JSON and deterministic Markdown rendering under docs/performance-tests/plans/. Include SHA-256 hashes for every generated executable. Use scripts/validate-plan.mjs to validate and fingerprint the JSON.
  5. Present the case matrix, excluded operations, executable hashes, exact commands, downloads, workload, measurements, reports, cleanup, and fingerprint. Stop until the user replies with unambiguous approval tied to that fingerprint.
  6. Revalidate the plan and executable hashes, then validate locality and prerequisites. Run a one-user functional smoke test for each case. Quarantine failed cases; abort the campaign when shared setup, authentication, health, or locality fails.
  7. Execute the approved campaign. Run isolated scenarios sequentially. Add a composite whole-application scenario only when the user approved traffic weights. Write raw output to .artifacts/ and return compact summaries from executors.
  8. Produce canonical JSON plus every selected report. Read references/bottlenecks.md, analyze relevant code paths, and distinguish observations, correlations, hypotheses, and confirmed causes. Stop locally started services, including Grafana and Prometheus, while preserving data volumes; remove volumes only after separate destructive-action approval.

Read the full file on GitHub · 34 lines

Files

What ships with it

46 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 · 34 lines · 97 tokens per session scan A 1431dfff6040

Subscribe to this mod's changes

performance-testing is a skill published in the GitHub repository felipepg22/FPGSkills (9 stars, last pushed 12d ago), licensed MIT. It adds 97 tokens to every session and 856 once invoked, about $0.0005 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 2026-08-31.

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