[HouMinXi]

Summary

claude-opus-5 gained its thinking-effort declaration in #14548. The same gap covers the rest of the thinking-capable Claude lineup on every first-party registry: Fable 5 and Opus 4.8/4.7/4.6/4.5 are seeded with supportsThinking in modelSpecs, but their registry entries never declared supportedThinkingEfforts. Because the catalog calls getThinkingCapabilityFields(..., skipCanonicalEffortFallback=true) for static registry models (catalog.ts:730-743), an entry without declared tiers gets no effort_tiers in /v1/models at all — clients cannot discover which effort levels these models accept.

This PR declares the tiers on all four first-party registries (claude, anthropic, github, ghe-copilot), following Anthropic's published per-model effort table:

Models	low	medium	high	xhigh	max
Opus 5 / Fable 5 / Opus 4.8 / Opus 4.7	✓	✓	✓	✓	✓
Opus 4.6	✓	✓	✓	—	✓
Opus 4.5	✓	✓	✓	—	—

xhigh was introduced with Opus 4.7, so 4.6/4.5 entries intentionally do not declare supportsXHighEffort. Fast variants (claude-opus-4.8-fast on github/ghe-copilot) mirror their base model. claude-opus-5 on the claude registry is left to #14548 so the two PRs merge cleanly in either order.

Tests

New tests/unit/claude-firstparty-effort-tiers.test.ts (7 tests):

• Every covered entry declares exactly the tier list from the table above, with supportsReasoning: true and supportsXHighEffort matching the tier list (present iff xhigh is included).
• getRegistryModelThinkingEfforts() resolves each entry — the lookup the catalog uses.
• Behavior lock for supportsXHighEffort() (providerModels.ts:372-387): the function defaults to true for models without an explicit flag, so Opus 4.6/4.5 correctness on the dotted-id registries depends on the canonical fallback reaching the claude registry's explicit false entries. These assertions pin that end-to-end so dropping those flags fails loudly instead of silently routing xhigh to models that reject it.

Mutation check: deleting the declared tiers from one entry per registry turns the suite red; restoring turns it green again.

Existing catalog/registry suites stay green (12058 canonical self-alias, 13601 collision names, 8327 owned-by prefix).

Notes

• Pre-existing display-name typos spotted while auditing (claude-sonnet-4.5 named "Claude Sonnet 4.6" in the anthropic registry; a similar one on the claude registry) are intentionally not fixed here to keep this diff scoped; happy to send a follow-up.
• Complements [defer] fix(providers): declare claude-opus-5 thinking efforts in claude registry #14548 (claude-registry opus-5) and fix(providers): declare Claude thinking-effort tiers on relay registries #14075 (relay registries); no overlap.