diff --git a/packages/opencode/src/util/effect-zod.ts b/packages/opencode/src/util/effect-zod.ts
new file mode 100644
index 00000000000..c1407594ca3
--- /dev/null
+++ b/packages/opencode/src/util/effect-zod.ts
@@ -0,0 +1,92 @@
+import { Schema, SchemaAST } from "effect"
+import z from "zod"
+
+export function zod<S extends Schema.Top>(schema: S): z.ZodType<Schema.Schema.Type<S>> {
+  return walk(schema.ast) as z.ZodType<Schema.Schema.Type<S>>
+}
+
+function walk(ast: SchemaAST.AST): z.ZodTypeAny {
+  const out = body(ast)
+  const desc = SchemaAST.resolveDescription(ast)
+  const ref = SchemaAST.resolveIdentifier(ast)
+  const next = desc ? out.describe(desc) : out
+  return ref ? next.meta({ ref }) : next
+}
+
+function body(ast: SchemaAST.AST): z.ZodTypeAny {
+  if (SchemaAST.isOptional(ast)) return opt(ast)
+
+  switch (ast._tag) {
+    case "String":
+      return z.string()
+    case "Number":
+      return z.number()
+    case "Boolean":
+      return z.boolean()
+    case "Null":
+      return z.null()
+    case "Undefined":
+      return z.undefined()
+    case "Any":
+    case "Unknown":
+      return z.unknown()
+    case "Never":
+      return z.never()
+    case "Literal":
+      return z.literal(ast.literal)
+    case "Union":
+      return union(ast)
+    case "Objects":
+      return object(ast)
+    case "Arrays":
+      return array(ast)
+    case "Declaration":
+      return decl(ast)
+    default:
+      return fail(ast)
+  }
+}
+
+function opt(ast: SchemaAST.AST): z.ZodTypeAny {
+  if (ast._tag !== "Union") return fail(ast)
+  const items = ast.types.filter((item) => item._tag !== "Undefined")
+  if (items.length === 1) return walk(items[0]).optional()
+  if (items.length > 1)
+    return z.union(items.map(walk) as [z.ZodTypeAny, z.ZodTypeAny, ...Array<z.ZodTypeAny>]).optional()
+  return z.undefined().optional()
+}
+
+function union(ast: SchemaAST.Union): z.ZodTypeAny {
+  const items = ast.types.map(walk)
+  if (items.length === 1) return items[0]
+  if (items.length < 2) return fail(ast)
+  return z.union(items as [z.ZodTypeAny, z.ZodTypeAny, ...Array<z.ZodTypeAny>])
+}
+
+function object(ast: SchemaAST.Objects): z.ZodTypeAny {
+  if (ast.propertySignatures.length === 0 && ast.indexSignatures.length === 1) {
+    const sig = ast.indexSignatures[0]
+    if (sig.parameter._tag !== "String") return fail(ast)
+    return z.record(z.string(), walk(sig.type))
+  }
+
+  if (ast.indexSignatures.length > 0) return fail(ast)
+
+  return z.object(Object.fromEntries(ast.propertySignatures.map((sig) => [String(sig.name), walk(sig.type)])))
+}
+
+function array(ast: SchemaAST.Arrays): z.ZodTypeAny {
+  if (ast.elements.length > 0) return fail(ast)
+  if (ast.rest.length !== 1) return fail(ast)
+  return z.array(walk(ast.rest[0]))
+}
+
+function decl(ast: SchemaAST.Declaration): z.ZodTypeAny {
+  if (ast.typeParameters.length !== 1) return fail(ast)
+  return walk(ast.typeParameters[0])
+}
+
+function fail(ast: SchemaAST.AST): never {
+  const ref = SchemaAST.resolveIdentifier(ast)
+  throw new Error(`unsupported effect schema: ${ref ?? ast._tag}`)
+}
diff --git a/packages/opencode/test/util/effect-zod.test.ts b/packages/opencode/test/util/effect-zod.test.ts
new file mode 100644
index 00000000000..4004ca2d231
--- /dev/null
+++ b/packages/opencode/test/util/effect-zod.test.ts
@@ -0,0 +1,61 @@
+import { describe, expect, test } from "bun:test"
+import { Schema } from "effect"
+
+import { zod } from "../../src/util/effect-zod"
+
+describe("util.effect-zod", () => {
+  test("converts class schemas for route dto shapes", () => {
+    class Method extends Schema.Class<Method>("ProviderAuthMethod")({
+      type: Schema.Union([Schema.Literal("oauth"), Schema.Literal("api")]),
+      label: Schema.String,
+    }) {}
+
+    const out = zod(Method)
+
+    expect(out.meta()?.ref).toBe("ProviderAuthMethod")
+    expect(
+      out.parse({
+        type: "oauth",
+        label: "OAuth",
+      }),
+    ).toEqual({
+      type: "oauth",
+      label: "OAuth",
+    })
+  })
+
+  test("converts structs with optional fields, arrays, and records", () => {
+    const out = zod(
+      Schema.Struct({
+        foo: Schema.optional(Schema.String),
+        bar: Schema.Array(Schema.Number),
+        baz: Schema.Record(Schema.String, Schema.Boolean),
+      }),
+    )
+
+    expect(
+      out.parse({
+        bar: [1, 2],
+        baz: { ok: true },
+      }),
+    ).toEqual({
+      bar: [1, 2],
+      baz: { ok: true },
+    })
+    expect(
+      out.parse({
+        foo: "hi",
+        bar: [1],
+        baz: { ok: false },
+      }),
+    ).toEqual({
+      foo: "hi",
+      bar: [1],
+      baz: { ok: false },
+    })
+  })
+
+  test("throws for unsupported tuple schemas", () => {
+    expect(() => zod(Schema.Tuple([Schema.String, Schema.Number]))).toThrow("unsupported effect schema")
+  })
+})