diff --git a/packages/opencode/src/provider/provider.ts b/packages/opencode/src/provider/provider.ts
index ccd3c55b4f1..69031bcc0fc 100644
--- a/packages/opencode/src/provider/provider.ts
+++ b/packages/opencode/src/provider/provider.ts
@@ -775,7 +775,7 @@ export namespace Provider {
         input: model.cost?.input ?? 0,
         output: model.cost?.output ?? 0,
         cache: {
-          read: model.cost?.cache_read ?? 0,
+          read: model.cost?.cache_read ?? model.cost?.input ?? 0,
           write: model.cost?.cache_write ?? 0,
         },
         experimentalOver200K: model.cost?.context_over_200k
@@ -947,7 +947,12 @@ export namespace Provider {
             input: model?.cost?.input ?? existingModel?.cost?.input ?? 0,
             output: model?.cost?.output ?? existingModel?.cost?.output ?? 0,
             cache: {
-              read: model?.cost?.cache_read ?? existingModel?.cost?.cache.read ?? 0,
+              read:
+                model?.cost?.cache_read ??
+                existingModel?.cost?.cache.read ??
+                model?.cost?.input ??
+                existingModel?.cost?.input ??
+                0,
               write: model?.cost?.cache_write ?? existingModel?.cost?.cache.write ?? 0,
             },
           },
diff --git a/packages/opencode/test/provider/provider.test.ts b/packages/opencode/test/provider/provider.test.ts
index 4c6eaf8b227..ab34f5741da 100644
--- a/packages/opencode/test/provider/provider.test.ts
+++ b/packages/opencode/test/provider/provider.test.ts
@@ -492,6 +492,98 @@ test("model cost defaults to zero when not specified", async () => {
   })
 })
 
+test("cache read cost falls back to input cost when not specified", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            "test-provider": {
+              name: "Test Provider",
+              npm: "@ai-sdk/openai-compatible",
+              env: [],
+              models: {
+                "test-model": {
+                  name: "Test Model",
+                  tool_call: true,
+                  limit: { context: 128000, output: 4096 },
+                  cost: {
+                    input: 5,
+                    output: 15,
+                  },
+                },
+              },
+              options: {
+                apiKey: "test-key",
+              },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      const providers = await Provider.list()
+      const model = providers["test-provider"].models["test-model"]
+      expect(model.cost.input).toBe(5)
+      expect(model.cost.output).toBe(15)
+      expect(model.cost.cache.read).toBe(5)
+      expect(model.cost.cache.write).toBe(0)
+    },
+  })
+})
+
+test("cache read cost uses explicit value when provided", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            "test-provider": {
+              name: "Test Provider",
+              npm: "@ai-sdk/openai-compatible",
+              env: [],
+              models: {
+                "test-model": {
+                  name: "Test Model",
+                  tool_call: true,
+                  limit: { context: 128000, output: 4096 },
+                  cost: {
+                    input: 5,
+                    output: 15,
+                    cache_read: 1,
+                    cache_write: 2,
+                  },
+                },
+              },
+              options: {
+                apiKey: "test-key",
+              },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      const providers = await Provider.list()
+      const model = providers["test-provider"].models["test-model"]
+      expect(model.cost.input).toBe(5)
+      expect(model.cost.output).toBe(15)
+      expect(model.cost.cache.read).toBe(1)
+      expect(model.cost.cache.write).toBe(2)
+    },
+  })
+})
+
 test("model options are merged from existing model", async () => {
   await using tmp = await tmpdir({
     init: async (dir) => {