When an agent configured with variant: "max" falls back from Opus to
Sonnet (or Haiku), the "max" variant was passed through unchanged.
OpenCode sends this as level: "max" to the Anthropic API, which rejects
it with: level "max" not supported, valid levels: low, medium, high
The anthropic-effort hook previously only handled Opus (inject effort=max)
and skipped all other Claude models. Now it actively clamps "max" → "high"
for non-Opus Claude models and mutates message.variant so OpenCode
doesn't pass the unsupported level to the API.
Ravi Tharuma