The static-stub sentence over-generalized: `tools` and `ToolCallError`
ARE bound at run time, and a model reading "everything below is a stub"
could stop catching `ToolCallError`. State the boundary and pin both
halves in the fixed-instruction assertions.
UNPRINTABLE missed U+0085: it is Cc but not ECMAScript whitespace, so
it survived the collapse and reached the docstring raw and invisible.
Add it and scope the docstring to Cc, since the `\xNN` escape cannot
address the Cf formatting characters that pass through by design.
Record the backend PR's two runtime contracts -- inject only `tools`
and `ToolCallError`, and bind the assembly-time language to the
request -- in the Agent Note and at requireCodeRuntime.
1b4cb031f0