SEP-2133 negotiates an extension from both sides, and a strict server
refuses skills/* to a client that did not declare
io.modelcontextprotocol/skills. The Inspector called those methods
without ever declaring it. Add it to ADVERTISABLE_EXTENSIONS, on by
default, which also gives it a Server Settings toggle.
Give the composable test server skillsRequireClientExtension and two
per-era strict showcase configs, so a strict server is reproducible here.
Writing the modern-era test exposed two defects the existing suite hid:
its "modern" cases set protocolEra on the transport config, which
InspectorClient does not read, so they connected on legacy; and once
they really ran modern, every skills result failed, because the modern
schemas required resultType, which the SDK codec checks and then lifts
off before a caller schema runs. Connect with versionNegotiation and
assert the era, and drop the resultType requirement (and the two modern
schema variants it was the only difference in).
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Q3RsrgCxVoFPokLB4vAkxi
Signed-off-by: cliffhall <cliff@futurescale.com>