inspector/CONTRIBUTING.md

Contributing to MCP Inspector

Thank you for your interest in improving the MCP Inspector. Contributors are genuinely valued — the goal of this document is to channel your input into a form we can act on quickly and consistently.

TL;DR

We accept issues, not pull requests. Design and implementation are done by the maintainers. If you've already built a fix or feature locally, share the prompt you used to produce it — not the source code. This applies to everyone outside the repo maintainers, including organization members who happen to have write access to this repository.

Why this policy exists

The Inspector v2 is developed with an AI-assisted, prompt-driven workflow built around a consistent architecture, a shared design system, and strict testing gates (see AGENTS.md). Every component follows the same conventions: "dumb" components that take data and callbacks as props, Mantine for all UI, theme variants instead of ad-hoc CSS, and a uniform per-file coverage gate of ≥ 90% on lines, statements, functions, and branches.

Accepting raw source PRs creates friction: a diff written outside this pipeline has to be reverse-engineered to fit our component/theme conventions, coverage gates, and review process — often it's faster to re-derive the change than to adapt the patch. Capturing your intent (a well-formed issue) or the prompt that generated your local change lets us reproduce the work inside our own workflow and standards, with the quality bar already baked in.

This policy is about efficiency, not gatekeeping. Your ideas, bug reports, and prompts directly shape what gets built. And if you'd like to contribute more than an issue, see Want to work on the Inspector with us? below — we'd rather bring you into the workflow than turn you away.

Who opens pull requests

Pull requests against this repository are opened by the repo maintainers only. That includes organization members with write access: being able to push a branch here isn't the same as being asked to — the constraint is the workflow described above, not permissions, so the same policy applies whether or not GitHub would let you click the button.

If you're not a repo maintainer, open a detailed issue instead and a maintainer will pick it up. If you've already prototyped the change locally, say so in the issue and include the prompt you used (see If you've already fixed it locally) — that's the fastest path from your work to a merged change.

Every pull request references an issue, including the maintainers' own. The PR body's first line is Closes #<ISSUE_NUMBER>. Work is tracked on the project board through issues, so a PR without one is invisible to the board — which is why a well-formed issue is the useful contribution here, and why writing one is never wasted effort.

How to contribute a bug report or feature request

Open a well-formed issue describing the bug or the feature you have in mind. A great issue gives us everything we need to act on it without a round-trip — see What makes a good issue or prompt submission below. That's the whole process: you describe the intent, we handle the design and implementation.

Which version and label?

The Inspector is maintained across two versions, each with its own base branch and version label. File your issue against the version your report or request targets:

Version	Base branch	Label	npm tag
v1	v1/main	v1	v1-latest
v2	v2/main	v2	latest

• v1 (v1/main) is the legacy Inspector — it takes security fixes only, and is published straight from that branch to the v1-latest npm tag (npx @modelcontextprotocol/inspector@v1-latest).
• v2 (v2/main) is where all current work happens — when in doubt, target v2. v2/main is the develop branch; it is merged into main at milestone releases, and main is what publishes the latest npm tag. Nothing targets main directly.

Label by version. Every issue (and the PRs maintainers open for it) must carry the label matching the target branch — v1 for v1/main and v2 for v2/main. This mirrors the "Label by version" convention documented in AGENTS.md.

If you've already fixed it locally

Please don't send a diff or open a pull request. Instead, open an issue that includes:

• The prompt(s) you used to generate the change — the exact text, so we can reproduce it through our own workflow.
• A description of the behavior before and after your change.
• How you verified it (steps you ran, tests you added, what you observed).

We'll reproduce the change through our pipeline so it lands with the right conventions, tests, and coverage.

What makes a good issue or prompt submission

A great submission gives us everything we need to act without a round-trip:

• Clear reproduction or use case — exact steps to reproduce a bug, or a concrete description of the feature and the problem it solves.
• Expected vs. actual behavior — what you saw, and what you expected instead.
• Affected client — which incarnation is involved: Web, TUI, or CLI (or "all" / "core" if it's shared logic).
• Environment details when relevant — OS, Node version, the MCP server you were inspecting, and any relevant config.
• The exact prompt text, if you generated a local change and want us to reproduce it.

Want to work on the Inspector with us?

The issues-only policy is about how unsolicited patches are handled — it is not a closed door. If you want to contribute at a deeper level, either in general or in a specific area, we'd genuinely like to hear from you:

• Join the MCP Contributor Discord and say hello in #inspector-dev. That's where day-to-day Inspector development is discussed and the fastest way to reach the maintainers.
• Attend the community calls at meet.modelcontextprotocol.io — see Contributor Communication for the full set of channels and how they're used.

From there we can scope a piece of work with you and supervise it through our workflow — which is also the path toward becoming a maintainer. What we want to avoid is drive-by diffs that have to be reverse-engineered into our pipeline; what we want to encourage is sustained, coordinated contribution.

All participation is governed by the MCP Code of Conduct.

Questions

If you're unsure how to scope something, open the issue anyway and say so — we'll help shape it. Thanks for helping make the Inspector better.