1b4cb031f0
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.