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Mads Hansen
Mads Hansen

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The MCP server you choose should pass an exit test

The easiest MCP server to adopt can become the hardest one to leave.

The endpoint is not the whole system.

Six months in, the real dependency includes:

  • tool schemas and versions
  • identity and tenant mappings
  • database roles and result limits
  • semantic definitions
  • redaction and approval policy
  • client configuration
  • audit evidence and test fixtures

So add a portability exercise to the MCP server comparison.

Pick one narrow, read-only workflow. Export its effective contract. Rebuild it in an empty target environment. Replay the same happy-path, denial, ambiguity, stale-schema, timeout, and cancellation cases.

Compare semantics and authority separately. Two implementations can return the same number while one uses broader permissions. They can also enforce the same permissions while calculating a business metric differently.

Then perform a canary cutover and a forced rollback.

Score every undocumented manual step, non-exportable policy, vendor-only identifier, and piece of audit history that cannot follow the workflow.

Protocol compatibility helps clients call tools.

Operational portability proves your team still owns the workflow.

Full test: MCP server comparison portability and exit test

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