Verified 2026-10-02 against code.claude.com/docs/en/model-config and
/sub-agents. On the Anthropic API opus -> Opus 5.5 and sonnet ->
Sonnet 5.5 (default effort medium), fable -> Fable 5.1 (default high).
Three more claims in the same section were false and are corrected:
an agent without effort: inherits the session level, not the model
default; MAX_THINKING_TOKENS=0 has no effect on Opus 5.5, Sonnet 5.5
or Fable; effort is capped by maxEffortLevel or an organization cap.
"Mythos-class" is replaced by the docs' own wording. History is
untouched (CHANGELOG, the measurement docs, the Path C line).
STATE said seven files but listed six; the red pin found exactly
these six. The end-state registry line names a CC changelog fact and
stays as history.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Kjell Tore Guttormsen
e4e37f91ef