CodeSampleX

CodeSampleX

Tested. Not guessed.

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Start here: CLI quick start · Use the public REST API without installing · Connect an MCP client

CLI quick start (Windows PowerShell)

Install, check the binary, then ask your first question in PowerShell:

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

csx version csx search "axios multipart upload" --package pkg:npm/axios

The installer asks you to choose JOIN COMMUNITY or LOCAL ONLY. Community mode warms the first cache and starts background sync; local-only mode disables automatic network access and may return no results from a cold cache. You can change modes later with csx init --community or csx init --local-only.

csx version prints csx v . Search returns answers graded for the detected environment; read each result's environment differences before using it. NO_SAFE_MATCH means no verified match was found, not that installation failed. Run searches from your project directory to include its dependency and runtime context.

If PowerShell cannot find csx, open a new terminal or check the installed binary with & "$env:LOCALAPPDATA\csx\csx.exe" version. For macOS / Linux and installation details, or MCP client setup, continue below.

What CodeSampleX records

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.* Reporters use rotating peer buckets; separate first-party activity analytics use a stable pseudonymous client ID, never a name or IP identity. See analytics semantics.

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.

No install needed to read the network

CodeSampleX exposes a public REST surface for agents, browsers and scripts. Every answer the site renders is a plain HTTPS request away — no key, no account, no client library, readable from any origin. Install the CLI only when you want local execution capture, the automatic failed-build hook, publishing or worker capabilities.

One request, real production JSON — copy it as it is:

curl 'https://codesamplex.dev/v2/search?package=pkg:npm/axios&symbol=axios.post&os=linux&runtime=node&runtimeVersion=22'

The answer carries a grade, and every result names which environment dimensions matched (exact[]) and which did not (different[]). A miss is spelled grade: "NO_SAFE_MATCH" — a real answer, not a failure to answer. A generic web-capable agent reads the whole contract from https://codesamplex.dev/skill.md; docs/rest.md is the same quick start for a person.

The three doors compared. Every mark is checked against the router and the command list by a test, and the Features page draws the same table:

REST reads the network. The CLI lets the network observe reality. MCP is an adapter on the CLI: csx mcp is the csx binary itself, so an MCP client on a host without csx has no server to talk to.

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: