Under the hood
Fixed a bug where a plugin tool call's staged output-file validation could check the wrong file's path
What
Staged MCP tool calls (calls to a plugin-provided tool that stage input and output files) validate each file's lane_path. This validation was restructured into one shared helper used for both input and output files. Previously, the code checking output files could reference the wrong file's path when reporting or validating an error, instead of the specific entry actually being checked.
Why
This fixes a bug where an error about an invalid output file path could point at the wrong file, which would be confusing when trying to diagnose a staging problem.