René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Freeform stopReasons in sampling responses are unsupported","articleBody":"**Bug description**\nThe spec defines some well-known `stopReason` values, but also allows arbitrary values to be passed as well ([spec](https://github.com/modelcontextprotocol/modelcontextprotocol/blob/f5ccad944fdf2b7d9cc70cf817f66ca5a8aa03a4/schema/2024-11-05/schema.ts#L807)). When parsing these, the Java SDK throws an exception:\n\n```\ncom.fasterxml.jackson.databind.exc.InvalidFormatException: Cannot deserialize value of type `io.modelcontextprotocol.spec.McpSchema$CreateMessageResult$StopReason` from String \"arbitrary value\": not one of the values accepted for Enum class: [endTurn, stopSequence, maxTokens]\n```\n\n**Environment**\nJDK21\n\n**Steps to reproduce**\nSee PR #327\n\n**Expected behavior**\nSDK does not throw\n\n**Minimal Complete Reproducible example**\nSee PR #327\n","author":{"url":"https://github.com/LucaButBoring","@type":"Person","name":"LucaButBoring"},"datePublished":"2025-06-19T21:09:53.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/328/java-sdk/issues/328"}