test: switch opus defaults to sonnet/kimi for cheaper coverage

- opencode test default: claude-sonnet-4-6 → moonshotai/kimi-k2. claude-code
  default stays on sonnet (the agent-under-test for that path is Claude
  Code); the opencode path doesn't need an Anthropic model.
- byok-no-keys-fallback fixture: anthropic/claude-opus → moonshotai/kimi-k2.
  test verifies fallback to opencode/big-pickle, so the configured model
  is never invoked; picking a non-opus alias avoids burning credits if
  the fallback ever regresses.
- BEDROCK_MODEL_ID in both test workflows: us.anthropic.claude-opus-4-6-v1
  → us.anthropic.claude-sonnet-4-6. env var is required by the ci.test
  invariant that every provider's env vars are wired into the workflow.

.github/workflows/test.yml

@@ -62,7 +62,7 @@ jobs:
       OPENCODE_API_KEY: ${{ secrets.OPENCODE_API_KEY }}
       AWS_BEARER_TOKEN_BEDROCK: ${{ secrets.AWS_BEARER_TOKEN_BEDROCK }}
       AWS_REGION: us-east-1
-      BEDROCK_MODEL_ID: us.anthropic.claude-opus-4-6-v1
+      BEDROCK_MODEL_ID: us.anthropic.claude-sonnet-4-6
       VERTEX_SERVICE_ACCOUNT_JSON: ${{ secrets.VERTEX_SERVICE_ACCOUNT_JSON }}
       GOOGLE_CLOUD_PROJECT: pullfrog
       VERTEX_LOCATION: global

test/agnostic/byokFallback.ts

@@ -3,7 +3,7 @@ import { defineFixture, getAgentOutput } from "../utils.ts";
 
 /**
  * BYOK-no-keys fallback test — proves that an account configured for a
- * BYOK model (here: `anthropic/claude-opus`) but with no provider API
+ * BYOK model (here: `moonshotai/kimi-k2`) but with no provider API
  * keys present in the runner env still gets a successful run by falling
  * back to a free OpenCode model.
  *
@@ -59,10 +59,10 @@ export const test: TestRunnerOptions = {
     BEDROCK_MODEL_ID: "",
     // configure a model that requires a BYOK key — the fallback only
     // engages when there's a configured model whose provider key is
-    // absent, so we have to pin one. anthropic/claude-opus is the
+    // absent, so we have to pin one. any BYOK alias works; we pick
-    // most common first-run choice (it's the catalog "preferred" for
+    // a cheap non-Anthropic model so the test doesn't burn opus
-    // the anthropic provider).
+    // credits if the fallback ever regresses.
-    PULLFROG_MODEL: "anthropic/claude-opus",
+    PULLFROG_MODEL: "moonshotai/kimi-k2",
   },
   tags: ["agnostic"],
   coverage: [

test/run.ts

@@ -312,7 +312,7 @@ async function runTestForAgent(ctx: RunContext): Promise<ValidationResult> {
     } else {
       const defaultModels: Record<string, string> = {
         claude: "anthropic/claude-sonnet-4-6",
-        opencode: "anthropic/claude-sonnet-4-6",
+        opencode: "moonshotai/kimi-k2",
       };
       const model = defaultModels[ctx.agent];
       if (model) {