AI Session Crash Doubled Form Fields, Exposing Idempotency Gap in MCP Tools

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A developer building a 12-field customer satisfaction survey with Claude Desktop ended up with 20 duplicate fields after an AI session timed out mid-task. When a new session was started and Claude was asked to continue, it re-added all 12 fields without checking which ones already existed, because the field_add tool performs a create operation rather than an upsert. The root cause is that field IDs are not treated as unique constraints by the server, so repeated calls simply generate new fields with auto-suffixed IDs. To address this, the developer adopted a find-before-add pattern, instructing Claude to first call field_list and then only add fields absent from the existing list. A subsequent update to the tool (v0.2.0) introduced a server-side AssessAgent pipeline that handles field creation atomically and idempotently, resolving the issue at the infrastructure level.

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