Minimal reproduction for a @mastra/core bug: a tool added by an input
processor's processInputStep (return { tools }) reaches its execute with
context.mastra === undefined (and context.memory === undefined), whereas a
statically-declared agent tool receives context.mastra on the same run.
Only tools that read context.mastra are affected (e.g. one that calls
mastra.getAgent(...) to run another agent).