diff --git a/models.ts b/models.ts
index 1717bda..d6484ec 100644
--- a/models.ts
+++ b/models.ts
@@ -360,6 +360,7 @@ export const providers = {
         resolve: "opencode/minimax-m2.5-free",
         envVars: [],
         isFree: true,
+        fallback: "opencode/big-pickle",
       },
     },
   }),
diff --git a/test/agnostic/byokFallback.ts b/test/agnostic/byokFallback.ts
index 477a10f..d487df3 100644
--- a/test/agnostic/byokFallback.ts
+++ b/test/agnostic/byokFallback.ts
@@ -29,7 +29,7 @@ const fixture = defineFixture(
 
 function validator(result: AgentResult): ValidationCheck[] {
   const output = getAgentOutput(result);
-  const fellBack = /fell back from .* to opencode\/minimax-m2\.5-free/.test(output);
+  const fellBack = /fell back from .* to opencode\/big-pickle/.test(output);
   return [
     { name: "run_succeeded", passed: result.success },
     { name: "fallback_logged", passed: fellBack },
diff --git a/utils/buildPullfrogFooter.test.ts b/utils/buildPullfrogFooter.test.ts
index 6a860a7..fc854be 100644
--- a/utils/buildPullfrogFooter.test.ts
+++ b/utils/buildPullfrogFooter.test.ts
@@ -4,17 +4,17 @@ import { buildPullfrogFooter } from "./buildPullfrogFooter.ts";
 describe("buildPullfrogFooter — fallbackFrom annotation", () => {
   it("renders the provider display name when fallbackFrom is set", () => {
     const footer = buildPullfrogFooter({
-      model: "opencode/minimax-m2.5-free",
+      model: "opencode/big-pickle",
       fallbackFrom: "anthropic/claude-opus",
     });
     expect(footer).toContain(
-      "Using `MiniMax M2.5` (free) (credentials for Anthropic not configured)"
+      "Using `Big Pickle` (free) (credentials for Anthropic not configured)"
     );
   });
 
   it("works for OpenAI's display name too", () => {
     const footer = buildPullfrogFooter({
-      model: "opencode/minimax-m2.5-free",
+      model: "opencode/big-pickle",
       fallbackFrom: "openai/gpt",
     });
     expect(footer).toContain("(credentials for OpenAI not configured)");
@@ -22,7 +22,7 @@ describe("buildPullfrogFooter — fallbackFrom annotation", () => {
 
   it("falls back to the raw provider key when the slug provider is unknown to the catalog", () => {
     const footer = buildPullfrogFooter({
-      model: "opencode/minimax-m2.5-free",
+      model: "opencode/big-pickle",
       fallbackFrom: "some-unknown/model",
     });
     expect(footer).toContain("(credentials for some-unknown not configured)");
diff --git a/utils/byokFallback.ts b/utils/byokFallback.ts
index ef28fcc..46f11aa 100644
--- a/utils/byokFallback.ts
+++ b/utils/byokFallback.ts
@@ -4,15 +4,14 @@ import { hasProviderKey } from "./apiKeys.ts";
  * Slug we fall back to when a BYOK-required model is configured but the
  * runner has no provider key in env. Picked because it's free
  * (`isFree: true`, `envVars: []` — see `action/models.ts`), stable, and
- * currently the strongest free OpenCode model in the catalog. If a
- * smarter free model is added later, update this single constant.
+ * currently served by OpenCode Zen without a key.
  *
  * The slug is intentionally hard-coded and not a config knob — the
  * fallback is a safety net, not a user-facing preference, and adding a
  * config surface here would just push the same "what to fall back to"
  * decision into another setting that goes stale the same way.
  */
-export const FREE_FALLBACK_SLUG = "opencode/minimax-m2.5-free";
+export const FREE_FALLBACK_SLUG = "opencode/big-pickle";
 
 export type FallbackDecision = { fallback: false } | { fallback: true; from: string; to: string };