plugin tools called with invalid enum params return enough information to self-heal

[khimaros]

Description

@rekram1-node #27770 fixed most of the issues with plugin tools, but it left one remaining issue: tools callied with an invalid enum param does not provide any information to the LLM.

Plugins

No response

OpenCode version

head

Steps to reproduce

1. create a plugin with a tool schema containing an enum
2. prompt the LLM so that it uses the tool with an invalid enum param

Screenshot and/or share link

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Operating System

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Terminal

No response

[Necmttn]

Tool validation failures should be structured tool results, not opaque provider errors. For invalid enum params, return schema path, bad value, allowed values, whether retry is safe, and the original tool call id. The model can then repair the next call deterministically, and logs can distinguish schema-invalid retries from tool runtime failures.

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