CodeSampleX

Tested. Not guessed.

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CodeSampleX is an open compatibility testing network for developer libraries, runtimes and toolchains. It does not summarize documentation and it does not collect anecdotes. It records what real builds actually did, in environments recorded rather than assumed — then shows you where things worked, where they broke, and in which environment.

Two things are the asset, and a third is a bonus:

• Evidence — real builds on real developer machines, with the environment, stage, structured termination, and secret-safe normalized failure fingerprint. Missing or legacy failure detail is shown as an Evidence gap, never invented as a cause. It arrives automatically wherever csx is installed, so it reaches platforms no container lane can: no container reproduces a macOS host — Docker on a Mac runs a Linux VM, which is a different machine wearing the same laptop — npm publishes no Windows image, and the long tail of musl, ARM, corporate base images and actually-installed runtime versions is unbounded. This is the only thing that can fill the map.
• Findings — the contradictions we detected in that evidence: what a competent developer or model expects, measured against what happened. These are ours to stand behind, and they are what a model most often gets wrong, because they are exactly what the documentation does not say.
• Samples — runnable code we write and verify ourselves. A bonus, deliberately: a container farm can never cover the space, so a verified sample is a confidence tier above the evidence, never the condition for having an answer at all.

Which is why a miss is not empty. When nothing has been proven for your case the grade stays NO_SAFE_MATCH — and the recorded observations come back with it, as recorded.

• Compatibility map: https://codesamplex.dev
• The question it answers: does it run there? — this API, on this version, on this OS, under this runtime.
• The answer it gives: here is what happened, and here is where it ran. Never who: reporters are anonymous peer buckets, and no identity is collected to show.

What ships today

CodeSampleX is no longer just a search command. The shipped product now exposes several surfaces, all backed by the same evidence model:

The CLI is the canonical local interface. csx help is generated from the commands in the binary; this table is pinned to it by a test so a new command cannot silently outgrow the README.

The network also installs an optional build-failure hook into supported coding agents. When an agent's shell build fails, the hook classifies the failing build step, sanitizes the error locally, searches CodeSampleX, and stays silent on a miss or unrelated command. csx hook status shows what is installed; csx hook check proves the registered hook path with a throwaway failing build.

Does it run there?

Every result is tied to the environment that produced it, so the same data can be pivoted into version × symbol, OS × runtime, version × architecture, browser/runtime, libc, and other recorded dimensions. Use the live compatibility explorer or a package page such as pgx/v5 for current counts; the README deliberately does not freeze live network numbers into a dated screenshot. The shape below is illustrative only:

                                         v5.10.0     v5.9.2
github.com/jackc/pgx/v5                  ▤ —         —
Batch                                    ▤ —         —

A matrix cell carries observations and, when available, a sample document. Observation counts say what recorded builds reached — compile, typecheck, test — and are counts of neither users nor machines. The sample document says that a reproducible contract exists at that coordinate; its state reflects those sample verification runs. Those two evidence classes are deliberately never added together.

A project compiling is therefore never presented as an individual symbol working. — remains unknown, and a missing sample remains a missing sample. The map records what happened at the coordinate instead of promoting a small set of runs into a universal PASS verdict.

Why testing matters

Documentation   → what should work
Code search     → how somebody used it
Community       → what somebody says worked
CodeSampleX     → what was actually tested

The rules that keep the map honest:

• A project compiling is never presented as a symbol working. Observations and verifications are counted separately and never summed.
• Unknown causes stay UNKNOWN. A wrong HIT is worse than a MISS — NO_SAFE_MATCH is a real answer.
• Evidence does not decay, and no cell is marked stale. An observation is one pinned release in one pinned environment bucket at one stage, and none of those move: that a build failed there is exactly as true a year later. What can change is the environment, and a different environment is a different cell.
• Failure causes are reported as probability distributions, never invented certainties.

Install the CLI

The CLI is the local tester: it wraps your real builds, turns their outcomes into anonymous evidence, and answers from the network.

Windows (PowerShell):

irm https://codesamplex.dev/install.ps1 | iex

macOS / Linux:

curl -fsSL https://codesamplex.dev/install.sh | sh

That line needs curl and CA certificates, which minimal images (debian-slim, alpine, most agent containers) do not have — and curl … | sh exits 0 when curl is missing, because a pipeline reports the last command's status. Install prerequisites first, or use wget:

apt-get install -y curl ca-certificates            # debian / ubuntu slim
apk add --no-cache curl ca-certificates            # alpine
wget -qO- https://codesamplex.dev/install.sh | sh  # needs neither

On Windows the installer keeps the stable launcher at %LOCALAPPDATA%\csx\csx.exe and adds %LOCALAPPDATA%\csx to the user PATH. On macOS/Linux the default is ${CSX_INSTALL_DIR:-$HOME/.local/bin}/csx; if that directory is not already on PATH, add it:

export PATH="$HOME/.local/bin:$PATH"
csx version    # install check — the supported spelling is `csx version`