Getting started

Capture your contract, compare a change, then protect the next pull request. Start in the hosted console, or use an approved preview CLI build.

#Start in the hosted console

MCP Inspect is a privately operated hosted product. Open app.mcprobe.dev/signup and create an account with an email address and a password of at least 12 characters. An organization and a first project are created for you. GitHub sign-in is not offered until its OAuth integration is configured.

To follow an HTTP MCP server, open Settings → Watched servers, enter the server's final public endpoint URL and choose a capture interval and alert threshold. Add an authorization header only if that server requires it. The first capture starts immediately; later captures compare the full contract. Discovery does not invoke tools and never sits in the server's request path.

Use the server's Changes view to review snapshots, compatibility findings and migration hints. A baseline establishes history; the next distinct contract provides a comparison. A failed capture is shown as a failure, not an unchanged contract. Watched servers cannot target private or loopback addresses.

#Local and CI preview access

The CLI, instrumentation and standalone Action are not publicly released yet. Use only builds supplied through approved preview access. The source repository is private; cloning it is not a public installation path. The npm package named mcp-inspect belongs to another project and must not be used for this product.

Once the preview CLI is installed, the local workflow below works without an account. Hosted usage queries, nightly rollups, account email delivery and paid checkout remain pending. Self-host deployments are not supported.

#1. Capture your baseline

From your server repository, with its normal build and environment ready:

mcp-inspect init --snapshot

This imports an existing MCP configuration, connects to the server and saves .mcp-inspect/surface.json. It discovers the advertised surface without calling any tools. A successful capture is your baseline, not a compatibility verdict.

If several servers are configured, select the one you maintain with --server <name>. If none is found, fill in the generated config's server command or URL, then run mcp-inspect snapshot. Use mcp-inspect doctor if the connection fails; it is a troubleshooting step, not a required extra capture.

Already have a configuration? Run mcp-inspect snapshot before editing the server. Already have two snapshots? Go straight to:

mcp-inspect diff before.json after.json

#2. Compare your change locally

Make your intended server change and rebuild it if needed. Keep the initial snapshot unchanged, then run:

mcp-inspect check --baseline-file .mcp-inspect/surface.json

The check captures the current server and compares it with your saved baseline. It does not overwrite that baseline. Read the changed entity, compatibility severity and migration hint together.

#Example report

This is an illustrative report; your own result depends on your server changes.

BREAKING (1)
  ! search
    `limit` changed from optional to required.
    → Accept calls that omit it for at least one release, applying the
      previous default, then require it.

POTENTIALLY_BREAKING (1)
  ~ create_issue
    Description changed. Agents may alter tool-selection behavior.
    → Review the wording and re-run your tool-selection evaluations.

A breaking finding exits 1 by default. A potentially breaking finding remains visible but only blocks when you choose fail_on: POTENTIALLY_BREAKING. Prose classification is a deterministic heuristic, not a measurement of model behavior. Understand severities.

An unchanged contract produces no changes. That is a completed comparison. “Comparison skipped — baseline needed” means no comparison happened, even though the command exits 0 so a setup PR can merge.

#3. Protect the next pull request

The standalone GitHub Action release is pending. The generated workflow currently references an unreleased Action location. Do not enable it as a working check yet. See GitHub Action details for preview access requirements.

After a verified Action release, generate its workflow:

mcp-inspect init --workflow

Review the generated .github/workflows/mcp-compatibility.yml, including your build command and any environment secrets the server needs. Commit it together with .mcp-inspect.yml and the baseline snapshot. Merge the baseline into your PR base branch before expecting CI to compare against it.

The first setup PR may report a skipped comparison. The next PR should show an actual comparison; the Action exposes compared=true when one ran.

After reviewing an intentional contract change, run mcp-inspect snapshot and commit the updated snapshot with the change. CI reads its baseline from the base branch, so it can still check that PR while the updated snapshot becomes the baseline after merge. GitHub Action details.

Do not hand-edit snapshots: their content and fingerprints are verified on read.

#4. Add shared history when you need it

The local check is fully usable without signup. To keep deployment history, open the hosted console and follow Add your first server: select a project, create an API key and run the supplied upload command. Setup is complete when the console receives the snapshot. A successful CLI exit alone does not confirm upload, because hosted failures are warnings.

In .mcp-inspect.yml, set endpoint: https://api.mcprobe.dev explicitly when using a source revision with the previous hosted default. The console is at app.mcprobe.dev. Usage queries and nightly rollups are pending the deployment's analytics read credential; account email delivery, GitHub sign-in and paid checkout are not configured yet.

Telemetry is a separate, optional step. You can capture, compare, gate pull requests and keep shared history without installing the SDK.