`read_file` exempted SKILL.md from every limit, and both injection paths
(`/skill` expansion and the `skill` tool) pasted the whole body. A 220 KB
skill put 55k tokens into the context on each call.
`cap_skill_body` cuts an over-cap body at the last line boundary that
fits (a char boundary when the body is one long line) and appends a note
that points at offset and limit. It runs before `apply_substitutions`, so
the arguments land after the cut. Both injection paths call it and log
the cut.
`read_file` returns a SKILL.md whole only while it fits the cap. Over the
cap it reads like any other file: offset and limit apply, and a window
that is still too large answers FileTooLarge. Without that the note would
send the model to a read that ignores its range.
`skill_file_skips_token_limit` pinned the exemption; it gives way to
`skill_file_over_cap_returns_file_too_large` and
`skill_file_over_cap_honors_offset_and_limit`, as upstream did.
Ported from upstream (grok-build tools skills/skill.rs cap_skill_body and
read_file skill_full, 1.0.33). Upstream's `max_output_bytes` read budget
in the same hunk is a feature and stays out.
ZacharyZhang-NY
206711bed5