[TomasRichtr]

Summary

Two fixes for running this plugin on OpenCode 2.x, both hit in practice on opencode 2.0.30 with Claude Pro/Max OAuth:

1. OpenCode v2 plugin support (closes OpenCode v2 support plans? #34) — v2 rejects the current entrypoint with:

   Plugin must export a default definition with an id and an effect or setup function
   

   V1 hooks never run under v2; moving the file or renaming the config entry is not enough.
2. thinking-binding-controls-2026-08-01 beta flag (ref Beta header rewrite breaks Opus 5.5, Sonnet 5.5 and Fable 5.1 on OpenCode 1.18.x #33) — OpenCode v2 natively adds thinking.block_binding to requests for models flagged supportsThinkingBlockBinding (claude-haiku-5-5 and other 5.x models). The API only accepts that field under the new beta, so with the old flag set those requests fail with:

   thinking.adaptive.block_binding: Extra inputs are not permitted
   

   The flag exists in Claude Code ≥ 2.1.2xx (verified against the 2.1.296 install).

Changes

fix: commit (constants.ts)

• Appends thinking-binding-controls-2026-08-01 to BETA_FLAGS, with a comment on how to re-derive the flag list from a Claude Code install (grep -aoE ... over the binary).

feat: commit (index.ts, tests, README, package.json)

• Adds setup() next to server() on the default export ({ id, setup, server }). opencode ≥ 2.0 uses setup() and ignores server(); 1.18.x keeps using server(). No new runtime dependencies.
• Maps the same behavior onto the v2 APIs:
  • auth.loader custom fetch → session.hook("http.request") (header/body/URL rewrite, provider-scoped to anthropic)
  • auth.loader response wrapping → session.hook("http.response") (SSE tool-name/argument translation)
  • experimental.chat.system.transform → session.hook("context")
  • auth.methods OAuth → integration.transform registering an oauth method override on the anthropic integration: authorize (Claude CLI keychain fast path, then browser PKCE via the existing local callback server) and a layered refresh callback whose result opencode persists
• Extracts the V1 fetch's body/URL/response phases into shared helpers (transformClaudeRequestBody, normalizeAnthropicApiUrl, wrapAnthropicResponseWithSse) so v1 and v2 share one wire-format implementation; splits refreshAuth into a pure refreshTokensLayered (the v2 refresh callback must return tokens rather than write the auth store itself, since v2 has no client.auth.set equivalent — opencode persists what the callback returns).
• Documented v2 divergences in the source: no model injection (the v2 models.dev catalog already lists Claude models), no inline 429 token rotation (Claude refresh tokens are single-use — rotating them anywhere but the persisted refresh callback invalidates the stored token), and rewrites apply to anthropic.com hosts only.
• Tests: new plugin module shape case asserts the { id, setup, server } shape, that the method override targets anthropic/oauth with async authorize/refresh (a plain-object return crashes v2's credential resolver — that one cost a debugging session), and that the three provider-scoped hooks register.

Testing

• npm run typecheck and npm test clean (123 tests).
• Both changes verified end-to-end on opencode 2.0.30 / macOS against a real Claude Pro account: plugin loads without the v2 error, expired stored credentials auto-refresh through the keychain layer and the refreshed credential is persisted, and requests on both claude-haiku-4-5 and claude-haiku-5-5 succeed (the latter previously 400ing on block_binding).

Versioning

Bumped to 1.11.0 — main already requires the { id, server } entrypoint (opencode ≥ 1.18.29), so adding setup breaks nothing that currently works. If you'd rather ship the v2 support as 2.0.0 (e.g. to drop the V1 path eventually), happy to change it.