diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 3f1a04f..02e6a3e 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -13,10 +13,10 @@ jobs:
     with:
       linux_5_9_enabled: false
       linux_5_10_enabled: false
-      linux_6_0_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -warnings-as-errors"
-      linux_6_1_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -warnings-as-errors"
-      linux_nightly_next_arguments_override: "--explicit-target-dependency-import-check error"
-      linux_nightly_main_arguments_override: "--explicit-target-dependency-import-check error"
+      linux_6_0_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -warnings-as-errors -Xswiftc -require-explicit-availability"
+      linux_6_1_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -warnings-as-errors -Xswiftc -require-explicit-availability"
+      linux_nightly_next_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -require-explicit-availability"
+      linux_nightly_main_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -require-explicit-availability"
 
   construct-plugin-tests-matrix:
     name: Construct plugin tests matrix
diff --git a/.github/workflows/pull_request.yml b/.github/workflows/pull_request.yml
index cdbf6de..9916556 100644
--- a/.github/workflows/pull_request.yml
+++ b/.github/workflows/pull_request.yml
@@ -25,10 +25,10 @@ jobs:
     with:
       linux_5_9_enabled: false
       linux_5_10_enabled: false
-      linux_6_0_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -warnings-as-errors"
-      linux_6_1_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -warnings-as-errors"
-      linux_nightly_next_arguments_override: "--explicit-target-dependency-import-check error"
-      linux_nightly_main_arguments_override: "--explicit-target-dependency-import-check error"
+      linux_6_0_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -warnings-as-errors -Xswiftc -require-explicit-availability"
+      linux_6_1_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -warnings-as-errors -Xswiftc -require-explicit-availability"
+      linux_nightly_next_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -require-explicit-availability"
+      linux_nightly_main_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -require-explicit-availability"
 
   construct-plugin-tests-matrix:
     name: Construct plugin tests matrix
diff --git a/Package.swift b/Package.swift
index 978748e..2337c52 100644
--- a/Package.swift
+++ b/Package.swift
@@ -39,7 +39,7 @@ let products: [Product] = [
 let dependencies: [Package.Dependency] = [
   .package(
     url: "https://github.com/grpc/grpc-swift.git",
-    from: "2.2.0"
+    from: "2.2.1"
   ),
   .package(
     url: "https://github.com/apple/swift-protobuf.git",
@@ -47,12 +47,28 @@ let dependencies: [Package.Dependency] = [
   ),
 ]
 
-let defaultSwiftSettings: [SwiftSetting] = [
-  .swiftLanguageMode(.v6),
-  .enableUpcomingFeature("ExistentialAny"),
-  .enableUpcomingFeature("InternalImportsByDefault"),
-  .enableUpcomingFeature("MemberImportVisibility"),
-]
+// -------------------------------------------------------------------------------------------------
+
+// This adds some build settings which allow us to map "@available(gRPCSwiftProtobuf 1.x, *)" to
+// the appropriate OS platforms.
+let nextMinorVersion = 3
+let availabilitySettings: [SwiftSetting] = (0 ... nextMinorVersion).map { minor in
+  let name = "gRPCSwiftProtobuf"
+  let version = "1.\(minor)"
+  let platforms = "macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0"
+  let setting = "AvailabilityMacro=\(name) \(version):\(platforms)"
+  return .enableExperimentalFeature(setting)
+}
+
+let defaultSwiftSettings: [SwiftSetting] =
+  availabilitySettings + [
+    .swiftLanguageMode(.v6),
+    .enableUpcomingFeature("ExistentialAny"),
+    .enableUpcomingFeature("InternalImportsByDefault"),
+    .enableUpcomingFeature("MemberImportVisibility"),
+  ]
+
+// -------------------------------------------------------------------------------------------------
 
 var targets: [Target] = [
   // protoc plugin for grpc-swift
@@ -190,13 +206,6 @@ if Context.buildCGRPCProtobuf {
 
 let package = Package(
   name: "grpc-swift-protobuf",
-  platforms: [
-    .macOS(.v15),
-    .iOS(.v18),
-    .tvOS(.v18),
-    .watchOS(.v11),
-    .visionOS(.v2),
-  ],
   products: products,
   dependencies: dependencies,
   targets: targets
diff --git a/Sources/GRPCProtobuf/Coding.swift b/Sources/GRPCProtobuf/Coding.swift
index 3160c08..90d15ab 100644
--- a/Sources/GRPCProtobuf/Coding.swift
+++ b/Sources/GRPCProtobuf/Coding.swift
@@ -18,6 +18,7 @@ public import GRPCCore
 public import SwiftProtobuf
 
 /// Serializes a Protobuf message into a sequence of bytes.
+@available(gRPCSwiftProtobuf 1.0, *)
 public struct ProtobufSerializer<Message: SwiftProtobuf.Message>: GRPCCore.MessageSerializer {
   public init() {}
 
@@ -41,6 +42,7 @@ public struct ProtobufSerializer<Message: SwiftProtobuf.Message>: GRPCCore.Messa
 }
 
 /// Deserializes a sequence of bytes into a Protobuf message.
+@available(gRPCSwiftProtobuf 1.0, *)
 public struct ProtobufDeserializer<Message: SwiftProtobuf.Message>: GRPCCore.MessageDeserializer {
   public init() {}
 
diff --git a/Sources/GRPCProtobuf/ContiguousBytesAdapter.swift b/Sources/GRPCProtobuf/ContiguousBytesAdapter.swift
index ee6db77..54df2f5 100644
--- a/Sources/GRPCProtobuf/ContiguousBytesAdapter.swift
+++ b/Sources/GRPCProtobuf/ContiguousBytesAdapter.swift
@@ -24,6 +24,7 @@ public import SwiftProtobuf  // internal but @usableFromInline
 /// it'd require a dependency on Protobuf in the core package), and `GRPCContiguousBytes` can't
 /// refine `SwiftProtobufContiguousBytes` for the same reason.
 @usableFromInline
+@available(gRPCSwiftProtobuf 1.0, *)
 struct ContiguousBytesAdapter<
   Bytes: GRPCContiguousBytes
 >: GRPCContiguousBytes, SwiftProtobufContiguousBytes {
diff --git a/Sources/GRPCProtobuf/Errors/ErrorDetails+AnyPacking.swift b/Sources/GRPCProtobuf/Errors/ErrorDetails+AnyPacking.swift
index 1fe4ee5..d3bd45c 100644
--- a/Sources/GRPCProtobuf/Errors/ErrorDetails+AnyPacking.swift
+++ b/Sources/GRPCProtobuf/Errors/ErrorDetails+AnyPacking.swift
@@ -61,6 +61,7 @@ extension Google_Protobuf_Any {
   }
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorDetails {
   // Note: this type isn't packable into an 'Any' protobuf so doesn't conform
   // to 'GoogleProtobufAnyPackable' despite holding types which are packable.
diff --git a/Sources/GRPCProtobuf/Errors/ErrorDetails+CustomStringConvertible.swift b/Sources/GRPCProtobuf/Errors/ErrorDetails+CustomStringConvertible.swift
index c781aaa..daee37a 100644
--- a/Sources/GRPCProtobuf/Errors/ErrorDetails+CustomStringConvertible.swift
+++ b/Sources/GRPCProtobuf/Errors/ErrorDetails+CustomStringConvertible.swift
@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorDetails: CustomStringConvertible {
   public var description: String {
     switch self.wrapped {
@@ -46,54 +47,63 @@ extension ErrorDetails: CustomStringConvertible {
 // Some errors use protobuf messages as their storage so the default description isn't
 // representative
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorDetails.ErrorInfo: CustomStringConvertible {
   public var description: String {
     "\(Self.self)(reason: \"\(self.reason)\", domain: \"\(self.domain)\", metadata: \(self.metadata))"
   }
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorDetails.DebugInfo: CustomStringConvertible {
   public var description: String {
     "\(Self.self)(stack: \(self.stack), detail: \"\(self.detail)\")"
   }
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorDetails.QuotaFailure.Violation: CustomStringConvertible {
   public var description: String {
     "\(Self.self)(subject: \"\(self.subject)\", violationDescription: \"\(self.violationDescription)\")"
   }
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorDetails.PreconditionFailure.Violation: CustomStringConvertible {
   public var description: String {
     "\(Self.self)(subject: \"\(self.subject)\", type: \"\(self.type)\", violationDescription: \"\(self.violationDescription)\")"
   }
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorDetails.BadRequest.FieldViolation: CustomStringConvertible {
   public var description: String {
     "\(Self.self)(field: \"\(self.field)\", violationDescription: \"\(self.violationDescription)\")"
   }
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorDetails.RequestInfo: CustomStringConvertible {
   public var description: String {
     "\(Self.self)(requestID: \"\(self.requestID)\", servingData: \"\(self.servingData)\")"
   }
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorDetails.ResourceInfo: CustomStringConvertible {
   public var description: String {
     "\(Self.self)(name: \"\(self.name)\", owner: \"\(self.owner)\", type: \"\(self.type)\", errorDescription: \"\(self.errorDescription)\")"
   }
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorDetails.Help.Link: CustomStringConvertible {
   public var description: String {
     "\(Self.self)(url: \"\(self.url)\", linkDescription: \"\(self.linkDescription)\")"
   }
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorDetails.LocalizedMessage: CustomStringConvertible {
   public var description: String {
     "\(Self.self)(locale: \"\(self.locale)\", message: \"\(self.message)\")"
diff --git a/Sources/GRPCProtobuf/Errors/ErrorDetails+Types.swift b/Sources/GRPCProtobuf/Errors/ErrorDetails+Types.swift
index 1a7f6b4..ba876d8 100644
--- a/Sources/GRPCProtobuf/Errors/ErrorDetails+Types.swift
+++ b/Sources/GRPCProtobuf/Errors/ErrorDetails+Types.swift
@@ -16,6 +16,7 @@
 
 internal import SwiftProtobuf
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorDetails {
   /// Describes the cause of the error with structured details.
   ///
diff --git a/Sources/GRPCProtobuf/Errors/ErrorDetails.swift b/Sources/GRPCProtobuf/Errors/ErrorDetails.swift
index 9619762..31bfcdb 100644
--- a/Sources/GRPCProtobuf/Errors/ErrorDetails.swift
+++ b/Sources/GRPCProtobuf/Errors/ErrorDetails.swift
@@ -24,6 +24,7 @@ public import SwiftProtobuf
 ///
 /// This type also allows you to provide wrap your own error details up as an "Any"
 /// protobuf (`Google_Protobuf_Any`).
+@available(gRPCSwiftProtobuf 1.0, *)
 public struct ErrorDetails: Sendable, Hashable {
   enum Wrapped: Sendable, Hashable {
     case errorInfo(ErrorInfo)
@@ -198,6 +199,7 @@ public struct ErrorDetails: Sendable, Hashable {
   }
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorDetails {
   /// Returns error info if set.
   public var errorInfo: ErrorInfo? {
diff --git a/Sources/GRPCProtobuf/Errors/GoogleRPCStatus.swift b/Sources/GRPCProtobuf/Errors/GoogleRPCStatus.swift
index 63ba327..6df2d46 100644
--- a/Sources/GRPCProtobuf/Errors/GoogleRPCStatus.swift
+++ b/Sources/GRPCProtobuf/Errors/GoogleRPCStatus.swift
@@ -35,6 +35,7 @@ public import SwiftProtobuf
 /// > inserted into the metadata keyed by "grpc-status-details-bin". The value of the metadata is
 /// > the serialized bytes of a "google.rpc.Status" protocol buffers message containing the status
 /// > code, message, and details.
+@available(gRPCSwiftProtobuf 1.0, *)
 public struct GoogleRPCStatus: Error, Hashable {
   /// A code representing the high-level domain of the error.
   public var code: RPCError.Code
@@ -73,6 +74,7 @@ public struct GoogleRPCStatus: Error, Hashable {
   }
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension GoogleRPCStatus {
   /// Creates a new message by decoding the given `SwiftProtobufContiguousBytes` value
   /// containing a serialized message in Protocol Buffer binary format.
@@ -133,6 +135,7 @@ extension GoogleRPCStatus {
   }
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension GoogleRPCStatus: RPCErrorConvertible {
   public var rpcErrorCode: RPCError.Code { self.code }
   public var rpcErrorMessage: String { self.message }
diff --git a/Sources/GRPCProtobuf/Errors/RPCError+GoogleRPCStatus.swift b/Sources/GRPCProtobuf/Errors/RPCError+GoogleRPCStatus.swift
index 56e9025..7a6e122 100644
--- a/Sources/GRPCProtobuf/Errors/RPCError+GoogleRPCStatus.swift
+++ b/Sources/GRPCProtobuf/Errors/RPCError+GoogleRPCStatus.swift
@@ -17,10 +17,12 @@
 public import GRPCCore
 internal import SwiftProtobuf
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension Metadata {
   static let statusDetailsBinKey = "grpc-status-details-bin"
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension RPCError {
   /// Unpack a ``GoogleRPCStatus`` error from the error metadata.
   ///
diff --git a/Sources/GRPCProtobufCodeGen/ProtobufCodeGenParser.swift b/Sources/GRPCProtobufCodeGen/ProtobufCodeGenParser.swift
index 3c4d9bc..6f61d76 100644
--- a/Sources/GRPCProtobufCodeGen/ProtobufCodeGenParser.swift
+++ b/Sources/GRPCProtobufCodeGen/ProtobufCodeGenParser.swift
@@ -32,6 +32,7 @@ internal import struct Foundation.IndexPath
 #endif
 
 /// Parses a ``FileDescriptor`` object into a ``CodeGenerationRequest`` object.
+@available(gRPCSwiftProtobuf 1.0, *)
 package struct ProtobufCodeGenParser {
   let extraModuleImports: [String]
   let protoToModuleMappings: ProtoFileToModuleMappings
@@ -99,6 +100,7 @@ package struct ProtobufCodeGenParser {
   }
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ProtobufCodeGenParser {
   fileprivate func codeDependencies(file: FileDescriptor) -> [Dependency] {
     guard file.services.count > 0 else {
@@ -141,6 +143,7 @@ extension ProtobufCodeGenParser {
   }
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension GRPCCodeGen.ServiceDescriptor {
   fileprivate init(
     descriptor: SwiftProtobufPluginLibrary.ServiceDescriptor,
@@ -168,6 +171,7 @@ extension GRPCCodeGen.ServiceDescriptor {
   }
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension GRPCCodeGen.MethodDescriptor {
   fileprivate init(
     descriptor: SwiftProtobufPluginLibrary.MethodDescriptor,
diff --git a/Sources/GRPCProtobufCodeGen/ProtobufCodeGenerator.swift b/Sources/GRPCProtobufCodeGen/ProtobufCodeGenerator.swift
index 55307c7..ef15404 100644
--- a/Sources/GRPCProtobufCodeGen/ProtobufCodeGenerator.swift
+++ b/Sources/GRPCProtobufCodeGen/ProtobufCodeGenerator.swift
@@ -17,6 +17,7 @@
 package import GRPCCodeGen
 package import SwiftProtobufPluginLibrary
 
+@available(gRPCSwiftProtobuf 1.0, *)
 package struct ProtobufCodeGenerator {
   internal var config: ProtobufCodeGenerator.Config
 
@@ -66,6 +67,7 @@ package struct ProtobufCodeGenerator {
   }
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ProtobufCodeGenerator {
   package struct Config {
     package var accessLevel: GRPCCodeGen.CodeGenerator.Config.AccessLevel
diff --git a/Sources/protoc-gen-grpc-swift/GenerateGRPC.swift b/Sources/protoc-gen-grpc-swift/GenerateGRPC.swift
index b6299b2..2272e65 100644
--- a/Sources/protoc-gen-grpc-swift/GenerateGRPC.swift
+++ b/Sources/protoc-gen-grpc-swift/GenerateGRPC.swift
@@ -26,6 +26,7 @@ import Foundation
 #endif
 
 @main
+@available(gRPCSwiftProtobuf 1.0, *)
 final class GenerateGRPC: SwiftProtobufPluginLibrary.CodeGenerator {
   var version: String? {
     Version.versionString
@@ -81,6 +82,7 @@ final class GenerateGRPC: SwiftProtobufPluginLibrary.CodeGenerator {
   }
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension GenerateGRPC {
   private func uniqueOutputFileName(
     fileDescriptor: FileDescriptor,
diff --git a/Sources/protoc-gen-grpc-swift/Options.swift b/Sources/protoc-gen-grpc-swift/Options.swift
index 5907ab1..f32f2e6 100644
--- a/Sources/protoc-gen-grpc-swift/Options.swift
+++ b/Sources/protoc-gen-grpc-swift/Options.swift
@@ -48,6 +48,7 @@ enum FileNaming: String {
   case dropPath = "DropPath"
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 struct GeneratorOptions {
   private(set) var protoToModuleMappings = ProtoFileToModuleMappings()
   private(set) var fileNaming = FileNaming.fullPath
@@ -191,6 +192,7 @@ struct GeneratorOptions {
   }
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension String.SubSequence {
   func trimmingWhitespaceAndNewlines() -> String {
     let trimmedSuffix = self.drop(while: { $0.isNewline || $0.isWhitespace })
@@ -199,6 +201,7 @@ extension String.SubSequence {
   }
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension GRPCCodeGen.CodeGenerator.Config.AccessLevel {
   fileprivate init?(protocOption value: String) {
     switch value {
diff --git a/Tests/GRPCProtobufCodeGenTests/ProtobufCodeGenParserTests.swift b/Tests/GRPCProtobufCodeGenTests/ProtobufCodeGenParserTests.swift
index c447588..13ee37e 100644
--- a/Tests/GRPCProtobufCodeGenTests/ProtobufCodeGenParserTests.swift
+++ b/Tests/GRPCProtobufCodeGenTests/ProtobufCodeGenParserTests.swift
@@ -27,20 +27,23 @@ struct ProtobufCodeGenParserTests {
     static let descriptorSetName = "test-service"
     static let fileDescriptorName = "test-service"
 
-    let codeGen: CodeGenerationRequest
-
-    init() throws {
-      let descriptor = try Self.fileDescriptor
-      self.codeGen = try parseDescriptor(descriptor)
+    @available(gRPCSwiftProtobuf 1.0, *)
+    var codeGen: CodeGenerationRequest {
+      get throws {
+        let descriptor = try Self.fileDescriptor
+        return try parseDescriptor(descriptor)
+      }
     }
 
     @Test("Filename")
-    func fileName() {
-      #expect(self.codeGen.fileName == "test-service.proto")
+    @available(gRPCSwiftProtobuf 1.0, *)
+    func fileName() throws {
+      #expect(try self.codeGen.fileName == "test-service.proto")
     }
 
     @Test("Leading trivia")
-    func leadingTrivia() {
+    @available(gRPCSwiftProtobuf 1.0, *)
+    func leadingTrivia() throws {
       let expected = """
         /// Leading trivia.
 
@@ -56,95 +59,112 @@ struct ProtobufCodeGenParserTests {
 
         """
 
-      #expect(self.codeGen.leadingTrivia == expected)
+      #expect(try self.codeGen.leadingTrivia == expected)
     }
 
     @Test("Dependencies")
-    func dependencies() {
+    @available(gRPCSwiftProtobuf 1.0, *)
+    func dependencies() throws {
       let expected: [GRPCCodeGen.Dependency] = [
         .init(module: "GRPCProtobuf", accessLevel: .internal),  // Always an internal import
         .init(module: "SwiftProtobuf", accessLevel: .internal),
       ]
-      #expect(self.codeGen.dependencies == expected)
+      #expect(try self.codeGen.dependencies == expected)
     }
 
     @Suite("Service")
     struct Service {
-      let service: GRPCCodeGen.ServiceDescriptor
-
-      init() throws {
-        let request = try parseDescriptor(try TestService.fileDescriptor)
-        try #require(request.services.count == 1)
-        self.service = try #require(request.services.first)
+      @available(gRPCSwiftProtobuf 1.0, *)
+      var service: GRPCCodeGen.ServiceDescriptor {
+        get throws {
+          let request = try parseDescriptor(try TestService.fileDescriptor)
+          try #require(request.services.count == 1)
+          return try #require(request.services.first)
+        }
       }
 
       @Test("Name")
-      func name() {
-        #expect(self.service.name.identifyingName == "test.TestService")
+      @available(gRPCSwiftProtobuf 1.0, *)
+      func name() throws {
+        #expect(try self.service.name.identifyingName == "test.TestService")
       }
 
       @Suite("Methods")
       struct Methods {
-        let unary: GRPCCodeGen.MethodDescriptor
-        let clientStreaming: GRPCCodeGen.MethodDescriptor
-        let serverStreaming: GRPCCodeGen.MethodDescriptor
-        let bidiStreaming: GRPCCodeGen.MethodDescriptor
-
-        init() throws {
-          let request = try parseDescriptor(try TestService.fileDescriptor)
-          #expect(request.services.count == 1)
-          let service = try #require(request.services.first)
+        @available(gRPCSwiftProtobuf 1.0, *)
+        var service: GRPCCodeGen.ServiceDescriptor {
+          get throws {
+            let request = try parseDescriptor(try TestService.fileDescriptor)
+            try #require(request.services.count == 1)
+            return try #require(request.services.first)
+          }
+        }
 
-          self.unary = service.methods[0]
-          self.clientStreaming = service.methods[1]
-          self.serverStreaming = service.methods[2]
-          self.bidiStreaming = service.methods[3]
+        @available(gRPCSwiftProtobuf 1.0, *)
+        var unary: GRPCCodeGen.MethodDescriptor {
+          get throws { try self.service.methods[0] }
+        }
+        @available(gRPCSwiftProtobuf 1.0, *)
+        var clientStreaming: GRPCCodeGen.MethodDescriptor {
+          get throws { try self.service.methods[1] }
+        }
+        @available(gRPCSwiftProtobuf 1.0, *)
+        var serverStreaming: GRPCCodeGen.MethodDescriptor {
+          get throws { try self.service.methods[2] }
+        }
+        @available(gRPCSwiftProtobuf 1.0, *)
+        var bidiStreaming: GRPCCodeGen.MethodDescriptor {
+          get throws { try self.service.methods[3] }
         }
 
         @Test("Documentation")
-        func documentation() {
-          #expect(self.unary.documentation == "/// Unary docs.\n")
-          #expect(self.clientStreaming.documentation == "/// Client streaming docs.\n")
-          #expect(self.serverStreaming.documentation == "/// Server streaming docs.\n")
-          #expect(self.bidiStreaming.documentation == "/// Bidirectional streaming docs.\n")
+        @available(gRPCSwiftProtobuf 1.0, *)
+        func documentation() throws {
+          #expect(try self.unary.documentation == "/// Unary docs.\n")
+          #expect(try self.clientStreaming.documentation == "/// Client streaming docs.\n")
+          #expect(try self.serverStreaming.documentation == "/// Server streaming docs.\n")
+          #expect(try self.bidiStreaming.documentation == "/// Bidirectional streaming docs.\n")
         }
 
         @Test("Name")
-        func name() {
-          #expect(self.unary.name.identifyingName == "Unary")
-          #expect(self.clientStreaming.name.identifyingName == "ClientStreaming")
-          #expect(self.serverStreaming.name.identifyingName == "ServerStreaming")
-          #expect(self.bidiStreaming.name.identifyingName == "BidirectionalStreaming")
+        @available(gRPCSwiftProtobuf 1.0, *)
+        func name() throws {
+          try #expect(self.unary.name.identifyingName == "Unary")
+          try #expect(self.clientStreaming.name.identifyingName == "ClientStreaming")
+          try #expect(self.serverStreaming.name.identifyingName == "ServerStreaming")
+          try #expect(self.bidiStreaming.name.identifyingName == "BidirectionalStreaming")
         }
 
         @Test("Input")
-        func input() {
-          #expect(self.unary.inputType == "Test_TestInput")
-          #expect(!self.unary.isInputStreaming)
+        @available(gRPCSwiftProtobuf 1.0, *)
+        func input() throws {
+          #expect(try self.unary.inputType == "Test_TestInput")
+          #expect(try !self.unary.isInputStreaming)
 
-          #expect(self.clientStreaming.inputType == "Test_TestInput")
-          #expect(self.clientStreaming.isInputStreaming)
+          #expect(try self.clientStreaming.inputType == "Test_TestInput")
+          #expect(try self.clientStreaming.isInputStreaming)
 
-          #expect(self.serverStreaming.inputType == "Test_TestInput")
-          #expect(!self.serverStreaming.isInputStreaming)
+          #expect(try self.serverStreaming.inputType == "Test_TestInput")
+          #expect(try !self.serverStreaming.isInputStreaming)
 
-          #expect(self.bidiStreaming.inputType == "Test_TestInput")
-          #expect(self.bidiStreaming.isInputStreaming)
+          #expect(try self.bidiStreaming.inputType == "Test_TestInput")
+          #expect(try self.bidiStreaming.isInputStreaming)
         }
 
         @Test("Output")
-        func output() {
-          #expect(self.unary.outputType == "Test_TestOutput")
-          #expect(!self.unary.isOutputStreaming)
+        @available(gRPCSwiftProtobuf 1.0, *)
+        func output() throws {
+          #expect(try self.unary.outputType == "Test_TestOutput")
+          #expect(try !self.unary.isOutputStreaming)
 
-          #expect(self.clientStreaming.outputType == "Test_TestOutput")
-          #expect(!self.clientStreaming.isOutputStreaming)
+          #expect(try self.clientStreaming.outputType == "Test_TestOutput")
+          #expect(try !self.clientStreaming.isOutputStreaming)
 
-          #expect(self.serverStreaming.outputType == "Test_TestOutput")
-          #expect(self.serverStreaming.isOutputStreaming)
+          #expect(try self.serverStreaming.outputType == "Test_TestOutput")
+          #expect(try self.serverStreaming.isOutputStreaming)
 
-          #expect(self.bidiStreaming.outputType == "Test_TestOutput")
-          #expect(self.bidiStreaming.isOutputStreaming)
+          #expect(try self.bidiStreaming.outputType == "Test_TestOutput")
+          #expect(try self.bidiStreaming.isOutputStreaming)
         }
       }
     }
@@ -155,51 +175,58 @@ struct ProtobufCodeGenParserTests {
     static let descriptorSetName = "foo-service"
     static let fileDescriptorName = "foo-service"
 
-    let codeGen: CodeGenerationRequest
-
-    init() throws {
-      let descriptor = try Self.fileDescriptor
-      self.codeGen = try parseDescriptor(descriptor)
+    @available(gRPCSwiftProtobuf 1.0, *)
+    var codeGen: CodeGenerationRequest {
+      get throws {
+        let descriptor = try Self.fileDescriptor
+        return try parseDescriptor(descriptor)
+      }
     }
 
     @Test("Name")
-    func name() {
-      #expect(self.codeGen.fileName == "foo-service.proto")
+    @available(gRPCSwiftProtobuf 1.0, *)
+    func name() throws {
+      #expect(try self.codeGen.fileName == "foo-service.proto")
     }
 
     @Test("Dependencies")
-    func dependencies() {
+    @available(gRPCSwiftProtobuf 1.0, *)
+    func dependencies() throws {
       let expected: [GRPCCodeGen.Dependency] = [
         .init(module: "GRPCProtobuf", accessLevel: .internal)  // Always an internal import
       ]
-      #expect(self.codeGen.dependencies == expected)
+      #expect(try self.codeGen.dependencies == expected)
     }
 
     @Test("Service1")
+    @available(gRPCSwiftProtobuf 1.0, *)
     func service1() throws {
-      let service = self.codeGen.services[0]
+      let service = try self.codeGen.services[0]
       #expect(service.name.identifyingName == "foo.FooService1")
       #expect(service.methods.count == 1)
     }
 
     @Test("Service1.Method")
+    @available(gRPCSwiftProtobuf 1.0, *)
     func service1Method() throws {
-      let method = self.codeGen.services[0].methods[0]
+      let method = try self.codeGen.services[0].methods[0]
       #expect(method.name.identifyingName == "Foo")
       #expect(method.inputType == "Foo_FooInput")
       #expect(method.outputType == "Foo_FooOutput")
     }
 
     @Test("Service2")
+    @available(gRPCSwiftProtobuf 1.0, *)
     func service2() throws {
-      let service = self.codeGen.services[1]
+      let service = try self.codeGen.services[1]
       #expect(service.name.identifyingName == "foo.FooService2")
       #expect(service.methods.count == 1)
     }
 
     @Test("Service2.Method")
+    @available(gRPCSwiftProtobuf 1.0, *)
     func service2Method() throws {
-      let method = self.codeGen.services[1].methods[0]
+      let method = try self.codeGen.services[1].methods[0]
       #expect(method.name.identifyingName == "Foo")
       #expect(method.inputType == "Foo_FooInput")
       #expect(method.outputType == "Foo_FooOutput")
@@ -211,18 +238,14 @@ struct ProtobufCodeGenParserTests {
     static var descriptorSetName: String { "bar-service" }
     static var fileDescriptorName: String { "bar-service" }
 
-    let codeGen: CodeGenerationRequest
-    let service: GRPCCodeGen.ServiceDescriptor
-
-    init() throws {
+    @Test("Service name")
+    @available(gRPCSwiftProtobuf 1.0, *)
+    func serviceName() throws {
       let descriptor = try Self.fileDescriptor
-      self.codeGen = try parseDescriptor(descriptor)
-      self.service = try #require(self.codeGen.services.first)
-    }
+      let codeGen = try parseDescriptor(descriptor)
+      let service = try #require(codeGen.services.first)
 
-    @Test("Service name")
-    func serviceName() {
-      #expect(self.service.name.identifyingName == "BarService")
+      #expect(service.name.identifyingName == "BarService")
     }
   }
 
@@ -231,20 +254,17 @@ struct ProtobufCodeGenParserTests {
     static let descriptorSetName = "wkt-service"
     static let fileDescriptorName = "wkt-service"
 
-    let codeGen: CodeGenerationRequest
-
-    init() throws {
+    @Test("Dependencies")
+    @available(gRPCSwiftProtobuf 1.0, *)
+    func dependencies() throws {
       let descriptor = try Self.fileDescriptor
-      self.codeGen = try parseDescriptor(descriptor)
-    }
+      let codeGen = try parseDescriptor(descriptor)
 
-    @Test("Dependencies")
-    func dependencies() {
       let expected: [Dependency] = [
         Dependency(module: "GRPCProtobuf", accessLevel: .internal),
         Dependency(module: "SwiftProtobuf", accessLevel: .internal),
       ]
-      #expect(self.codeGen.dependencies == expected)
+      #expect(codeGen.dependencies == expected)
     }
   }
 }
diff --git a/Tests/GRPCProtobufCodeGenTests/ProtobufCodeGeneratorTests.swift b/Tests/GRPCProtobufCodeGenTests/ProtobufCodeGeneratorTests.swift
index 86e5ec4..414dd5f 100644
--- a/Tests/GRPCProtobufCodeGenTests/ProtobufCodeGeneratorTests.swift
+++ b/Tests/GRPCProtobufCodeGenTests/ProtobufCodeGeneratorTests.swift
@@ -48,6 +48,7 @@ struct ProtobufCodeGeneratorTests {
       }
     }
 
+    @available(gRPCSwiftProtobuf 1.0, *)
     @Test(
       "Generate",
       arguments: [CodeGenerator.Config.AccessLevel.internal],
@@ -1103,6 +1104,7 @@ struct ProtobufCodeGeneratorTests {
     }
 
     @Test("Generate with different module names")
+    @available(gRPCSwiftProtobuf 1.0, *)
     func generateWithDifferentModuleNames() throws {
       var config = ProtobufCodeGenerator.Config.defaults
       let defaultNames = config.moduleNames
@@ -1138,6 +1140,7 @@ struct ProtobufCodeGeneratorTests {
     static let fileDescriptorName = "foo-messages"
 
     @Test("Generate")
+    @available(gRPCSwiftProtobuf 1.0, *)
     func generate() throws {
       var config: ProtobufCodeGenerator.Config = .defaults
       config.accessLevel = .public
diff --git a/Tests/GRPCProtobufCodeGenTests/Utilities.swift b/Tests/GRPCProtobufCodeGenTests/Utilities.swift
index de227e7..b8c617a 100644
--- a/Tests/GRPCProtobufCodeGenTests/Utilities.swift
+++ b/Tests/GRPCProtobufCodeGenTests/Utilities.swift
@@ -68,6 +68,7 @@ private func loadDescriptorSet(
   return DescriptorSet(proto: descriptorSet)
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 func parseDescriptor(
   _ descriptor: FileDescriptor,
   extraModuleImports: [String] = [],
diff --git a/Tests/GRPCProtobufTests/Errors/DetailedErrorTests.swift b/Tests/GRPCProtobufTests/Errors/DetailedErrorTests.swift
index 7c49075..c9a77da 100644
--- a/Tests/GRPCProtobufTests/Errors/DetailedErrorTests.swift
+++ b/Tests/GRPCProtobufTests/Errors/DetailedErrorTests.swift
@@ -40,6 +40,7 @@ struct DetailedErrorTests {
       (["Help", "Help", "Help"], [.help(.testValue), .help(.testValue), .help(.testValue)]),
     ] as [([String], [ErrorDetails])]
   )
+  @available(gRPCSwiftProtobuf 1.0, *)
   func rpcStatus(details: [String], expected: [ErrorDetails]) async throws {
     let inProcess = InProcessTransport()
     try await withGRPCServer(transport: inProcess.server, services: [ErrorThrowingService()]) { _ in
@@ -95,11 +96,13 @@ struct DetailedErrorTests {
       (.localizedMessage(.testValue), #"LocalizedMessage(locale: "l", message: "m")"#),
     ] as [(ErrorDetails, String)]
   )
+  @available(gRPCSwiftProtobuf 1.0, *)
   func errorInfoDescription(_ details: ErrorDetails, expected: String) {
     #expect(String(describing: details) == expected)
   }
 
   @Test("Round-trip encoding of GoogleRPCStatus")
+  @available(gRPCSwiftProtobuf 1.0, *)
   func googleRPCStatusRoundTripCoding() throws {
     let detail = ErrorDetails.BadRequest(violations: [.init(field: "foo", description: "bar")])
     let status = GoogleRPCStatus(code: .dataLoss, message: "Uh oh", details: [.badRequest(detail)])
@@ -113,6 +116,7 @@ struct DetailedErrorTests {
   }
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 private struct ErrorThrowingService: ErrorService.SimpleServiceProtocol {
   func throwError(
     request: ThrowInput,
@@ -183,14 +187,17 @@ private struct ErrorThrowingService: ErrorService.SimpleServiceProtocol {
   }
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorDetails.ErrorInfo {
   fileprivate static let testValue = Self(reason: "r", domain: "d", metadata: ["k": "v"])
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorDetails.RetryInfo {
   fileprivate static let testValue = Self(delay: .seconds(1))
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorDetails.DebugInfo {
   fileprivate static let testValue = Self(
     stack: ["foo.foo()", "foo.bar()"],
@@ -198,6 +205,7 @@ extension ErrorDetails.DebugInfo {
   )
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorDetails.QuotaFailure {
   fileprivate static let testValue = Self(
     violations: [
@@ -206,6 +214,7 @@ extension ErrorDetails.QuotaFailure {
   )
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorDetails.PreconditionFailure {
   fileprivate static let testValue = Self(
     violations: [
@@ -214,6 +223,7 @@ extension ErrorDetails.PreconditionFailure {
   )
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorDetails.BadRequest {
   fileprivate static let testValue = Self(
     violations: [
@@ -222,14 +232,17 @@ extension ErrorDetails.BadRequest {
   )
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorDetails.RequestInfo {
   fileprivate static let testValue = Self(requestID: "id", servingData: "d")
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorDetails.ResourceInfo {
   fileprivate static let testValue = Self(type: "t", name: "n", errorDescription: "d")
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorDetails.Help {
   fileprivate static let testValue = Self(
     links: [
@@ -238,6 +251,7 @@ extension ErrorDetails.Help {
   )
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorDetails.LocalizedMessage {
   fileprivate static let testValue = Self(locale: "l", message: "m")
 }
diff --git a/Tests/GRPCProtobufTests/Errors/Generated/error-service.grpc.swift b/Tests/GRPCProtobufTests/Errors/Generated/error-service.grpc.swift
index 9096079..c675a71 100644
--- a/Tests/GRPCProtobufTests/Errors/Generated/error-service.grpc.swift
+++ b/Tests/GRPCProtobufTests/Errors/Generated/error-service.grpc.swift
@@ -30,7 +30,7 @@ internal import SwiftProtobuf
 // MARK: - ErrorService
 
 /// Namespace containing generated types for the "ErrorService" service.
-@available(macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0, *)
+@available(gRPCSwiftProtobuf 1.0, *)
 internal enum ErrorService {
     /// Service descriptor for the "ErrorService" service.
     internal static let descriptor = GRPCCore.ServiceDescriptor(fullyQualifiedService: "ErrorService")
@@ -55,7 +55,7 @@ internal enum ErrorService {
     }
 }
 
-@available(macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0, *)
+@available(gRPCSwiftProtobuf 1.0, *)
 extension GRPCCore.ServiceDescriptor {
     /// Service descriptor for the "ErrorService" service.
     internal static let ErrorService = GRPCCore.ServiceDescriptor(fullyQualifiedService: "ErrorService")
@@ -63,7 +63,7 @@ extension GRPCCore.ServiceDescriptor {
 
 // MARK: ErrorService (server)
 
-@available(macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0, *)
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorService {
     /// Streaming variant of the service protocol for the "ErrorService" service.
     ///
@@ -137,7 +137,7 @@ extension ErrorService {
 }
 
 // Default implementation of 'registerMethods(with:)'.
-@available(macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0, *)
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorService.StreamingServiceProtocol {
     internal func registerMethods<Transport>(with router: inout GRPCCore.RPCRouter<Transport>) where Transport: GRPCCore.ServerTransport {
         router.registerHandler(
@@ -155,7 +155,7 @@ extension ErrorService.StreamingServiceProtocol {
 }
 
 // Default implementation of streaming methods from 'StreamingServiceProtocol'.
-@available(macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0, *)
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorService.ServiceProtocol {
     internal func throwError(
         request: GRPCCore.StreamingServerRequest<ThrowInput>,
@@ -170,7 +170,7 @@ extension ErrorService.ServiceProtocol {
 }
 
 // Default implementation of methods from 'ServiceProtocol'.
-@available(macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0, *)
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorService.SimpleServiceProtocol {
     internal func throwError(
         request: GRPCCore.ServerRequest<ThrowInput>,
@@ -188,7 +188,7 @@ extension ErrorService.SimpleServiceProtocol {
 
 // MARK: ErrorService (client)
 
-@available(macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0, *)
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorService {
     /// Generated client protocol for the "ErrorService" service.
     ///
@@ -264,7 +264,7 @@ extension ErrorService {
 }
 
 // Helpers providing default arguments to 'ClientProtocol' methods.
-@available(macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0, *)
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorService.ClientProtocol {
     /// Call the "ThrowError" method.
     ///
@@ -293,7 +293,7 @@ extension ErrorService.ClientProtocol {
 }
 
 // Helpers providing sugared APIs for 'ClientProtocol' methods.
-@available(macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0, *)
+@available(gRPCSwiftProtobuf 1.0, *)
 extension ErrorService.ClientProtocol {
     /// Call the "ThrowError" method.
     ///
diff --git a/Tests/GRPCProtobufTests/ProtobufCodingTests.swift b/Tests/GRPCProtobufTests/ProtobufCodingTests.swift
index 6f30adf..9306238 100644
--- a/Tests/GRPCProtobufTests/ProtobufCodingTests.swift
+++ b/Tests/GRPCProtobufTests/ProtobufCodingTests.swift
@@ -19,6 +19,7 @@ import GRPCProtobuf
 import SwiftProtobuf
 import XCTest
 
+@available(gRPCSwiftProtobuf 1.0, *)
 final class ProtobufCodingTests: XCTestCase {
   func testSerializeDeserializeRoundtrip() throws {
     let message = Google_Protobuf_Timestamp.with {
@@ -73,6 +74,7 @@ final class ProtobufCodingTests: XCTestCase {
   }
 }
 
+@available(gRPCSwiftProtobuf 1.0, *)
 struct TestMessage: SwiftProtobuf.Message {
   var text: String = ""
   var unknownFields = SwiftProtobuf.UnknownStorage()
diff --git a/dev/protos/generate.sh b/dev/protos/generate.sh
index e9244aa..5af02e8 100755
--- a/dev/protos/generate.sh
+++ b/dev/protos/generate.sh
@@ -94,7 +94,7 @@ function generate_error_service {
   output="$root/Tests/GRPCProtobufTests/Errors/Generated"
 
   generate_message "$proto" "$(dirname "$proto")" "$output" "Visibility=Internal" "UseAccessLevelOnImports=true"
-  generate_grpc "$proto" "$(dirname "$proto")" "$output" "Visibility=Internal" "UseAccessLevelOnImports=true"
+  generate_grpc "$proto" "$(dirname "$proto")" "$output" "Visibility=Internal" "UseAccessLevelOnImports=true" "Availability=gRPCSwiftProtobuf 1.0"
 }
 
 #- DESCRIPTOR SETS ------------------------------------------------------------