codspeed-setup-harness

A setup workflow for adding performance benchmarks and connecting them to CodSpeed, a service that measures and tracks code speed.

In plain words
What is it for?
Use it to inspect a project, find code worth measuring, choose a supported benchmark framework, configure CodSpeed, and add performance tests.
Why use it?
It helps create representative tests for performance-critical code and avoids a benchmark setup that produces results which are difficult to compare or maintain.

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/codspeedhq/codspeed/codspeed-setup-harness
Any agent
npx skills add CodSpeedHQ/codspeed --skill codspeed-setup-harness
Clone the repo
git clone --depth 1 https://github.com/CodSpeedHQ/codspeed

Made for: Claude Code, Codex.

Per session 120 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,305 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 $0.00120 $0.02305
Opus 5 $0.00060 $0.01153
Sonnet 5 $0.00024 $0.00461
Haiku 4.5 $0.00012 $0.00231

Measured 2d ago against content hash a0058960f044, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

codspeed-setup-harness 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.

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/codspeed-setup-harness/SKILL.md · 322 lines

How it starts

The opening of the file, as written. The whole thing — 322 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Setup Harness

You are a performance engineer helping set up benchmarks and CodSpeed integration for a project. Your goal is to create useful, representative benchmarks and wire them up so CodSpeed can measure and track performance.

Step 1: Analyze the project

Before writing any benchmark code, understand what you're working with:

  1. Detect the language and build system: Look at the project structure, package files (Cargo.toml, package.json, pyproject.toml, go.mod, CMakeLists.txt), and source files.

  2. Identify existing benchmarks: Check for benchmark files, codspeed.yml, CI workflows mentioning CodSpeed or benchmarks.

  3. Identify hot paths: Look at the codebase to understand what the performance-critical code is. Public API functions, data processing pipelines, I/O-heavy operations, and algorithmic code are good candidates.

  4. Check CodSpeed auth: Ensure codspeed auth login has been run.

Step 2: Choose the right approach

Based on the language and what the user wants to benchmark, pick the right harness:

Language-specific harnesses (recommended when available)

These integrate deeply with CodSpeed and provide per-benchmark flamegraphs, fine-grained comparison, and simulation mode support.

Language Framework How to set up
Rust divan (recommended), criterion, bencher Add codspeed-<framework>-compat as dependency using cargo add --rename
Python pytest-benchmark Install pytest-codspeed, use @pytest.benchmark or benchmark fixture
Node.js vitest (recommended), tinybench v5, benchmark.js Install @codspeed/<framework>-plugin, configure in vitest/test config
Go go test -bench No packages needed — CodSpeed instruments go test -bench directly
C/C++ Google Benchmark Build with CMake, CodSpeed instruments via valgrind-codspeed

Read the full file on GitHub · 322 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. 2d ago First seen · 322 lines · 120 tokens per session scan A a0058960f044

Subscribe to this mod's changes

codspeed-setup-harness is a skill published in the GitHub repository CodSpeedHQ/codspeed (281 stars, last pushed today), licensed Apache-2.0. It adds 120 tokens to every session and 2,305 once invoked, about $0.0006 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 2026-08-30.

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