diff --git a/CHANGELOG.md b/CHANGELOG.md
index 67ac924..f3fac62 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,9 @@
 
 ## 0.13.5 - Unreleased
 
+### JSON-RPC
+- fix: let non-interactive RPC startup proceed without a Contacts prompt while rejecting ambiguous name targets when Contacts is unavailable (#186, #187, thanks @SebTardif).
+
 ## 0.13.4 - 2026-07-27
 
 ### Highlights
diff --git a/Sources/imsg/ChatTargetResolver.swift b/Sources/imsg/ChatTargetResolver.swift
index af8b966..628ede0 100644
--- a/Sources/imsg/ChatTargetResolver.swift
+++ b/Sources/imsg/ChatTargetResolver.swift
@@ -114,6 +114,11 @@ enum ChatTargetResolver {
     contacts: any ContactResolving
   ) throws -> String {
     guard looksLikeContactName(recipient) else { return recipient }
+    guard !contacts.contactsUnavailable else {
+      throw IMsgError.invalidChatTarget(
+        "Contacts access is unavailable; specify a phone number or email instead."
+      )
+    }
     let matches = contacts.searchByName(recipient)
     switch matches.count {
     case 0:
diff --git a/Sources/imsg/Commands/RpcCommand.swift b/Sources/imsg/Commands/RpcCommand.swift
index bff73ee..c94dcae 100644
--- a/Sources/imsg/Commands/RpcCommand.swift
+++ b/Sources/imsg/Commands/RpcCommand.swift
@@ -2,7 +2,28 @@ import Commander
 import Foundation
 import IMsgCore
 
+#if canImport(Darwin)
+  import Darwin
+#elseif canImport(Glibc)
+  import Glibc
+#endif
+
 enum RpcCommand {
+  /// Contacts policy for RPC startup.
+  ///
+  /// Headless RPC (stdin not a TTY: LaunchAgent, pipes, automation) must not
+  /// block on a Contacts prompt that will never resolve while authorization
+  /// remains `.notDetermined`. Interactive terminals keep the prompt-capable
+  /// path so Contacts-backed name resolution still works.
+  static var startupContactsAccessPolicy: ContactsAccessPolicy {
+    contactsAccessPolicy(stdinIsTTY: isatty(STDIN_FILENO) != 0)
+  }
+
+  /// Pure policy helper for tests and callers that already know interactivity.
+  static func contactsAccessPolicy(stdinIsTTY: Bool) -> ContactsAccessPolicy {
+    stdinIsTTY ? .requestIfNeeded : .skipIfNotDetermined
+  }
+
   static let spec = CommandSpec(
     name: "rpc",
     abstract: "Run JSON-RPC over stdin/stdout",
@@ -15,6 +36,16 @@ enum RpcCommand {
       "imsg rpc --db ~/Library/Messages/chat.db",
     ]
   ) { values, runtime in
+    try await run(values: values, runtime: runtime)
+  }
+
+  static func run(
+    values: ParsedValues,
+    runtime: RuntimeOptions,
+    contactResolverFactory: @escaping () async -> any ContactResolving = {
+      await ContactResolver.create(accessPolicy: startupContactsAccessPolicy)
+    }
+  ) async throws {
     let dbPath = values.option("db") ?? MessageStore.defaultPath
     let store: MessageStore
     do {
@@ -23,7 +54,7 @@ enum RpcCommand {
       await RPCStartupErrorServer(error: error).run()
       throw CommandOutputEmittedError()
     }
-    let contacts = await ContactResolver.create()
+    let contacts = await contactResolverFactory()
     let server = RPCServer(store: store, verbose: runtime.verbose, contactResolver: contacts)
     try await server.run()
   }
diff --git a/Tests/imsgTests/ContactResolutionTests.swift b/Tests/imsgTests/ContactResolutionTests.swift
index 2d5865e..df3cb4e 100644
--- a/Tests/imsgTests/ContactResolutionTests.swift
+++ b/Tests/imsgTests/ContactResolutionTests.swift
@@ -25,6 +25,14 @@ func contactNameResolutionPassesThroughUnknownNames() throws {
   #expect(resolved == "Unknown Person")
 }
 
+@Test
+func contactNameResolutionRejectsNamesWhenContactsAreUnavailable() {
+  let resolver = MockContactResolver(contactsUnavailable: true)
+  #expect(throws: (any Error).self) {
+    try ChatTargetResolver.resolveRecipientName("Unknown Person", contacts: resolver)
+  }
+}
+
 @Test
 func contactNameResolutionReturnsUniqueMatch() throws {
   let resolver = MockContactResolver(
diff --git a/Tests/imsgTests/RPCServerTests.swift b/Tests/imsgTests/RPCServerTests.swift
index 3ca80d1..ceb30ef 100644
--- a/Tests/imsgTests/RPCServerTests.swift
+++ b/Tests/imsgTests/RPCServerTests.swift
@@ -222,6 +222,28 @@ func rpcSendRejectsAmbiguousContactName() async throws {
   #expect(int64Value(error?["code"]) == -32602)
 }
 
+@Test
+func rpcSendRejectsContactNameWhenContactsAreUnavailable() async throws {
+  let store = try CommandTestDatabase.makeStoreForRPC()
+  let output = TestRPCOutput()
+  let resolver = MockContactResolver(contactsUnavailable: true)
+  var didSend = false
+  let server = RPCServer(
+    store: store,
+    verbose: false,
+    output: output,
+    sendMessage: { _ in didSend = true },
+    contactResolver: resolver
+  )
+
+  let line = #"{"jsonrpc":"2.0","id":"3u","method":"send","params":{"to":"Alice","text":"yo"}}"#
+  await server.handleLineForTesting(line)
+
+  let error = output.errors.first?["error"] as? [String: Any]
+  #expect(int64Value(error?["code"]) == -32602)
+  #expect(didSend == false)
+}
+
 @Test
 func rpcSendReturnsSentMessageIdentifiersWhenResolved() async throws {
   let store = try CommandTestDatabase.makeStoreForRPC()
diff --git a/Tests/imsgTests/RpcCommandContactsPolicyTests.swift b/Tests/imsgTests/RpcCommandContactsPolicyTests.swift
new file mode 100644
index 0000000..16c4bbc
--- /dev/null
+++ b/Tests/imsgTests/RpcCommandContactsPolicyTests.swift
@@ -0,0 +1,17 @@
+import Foundation
+import IMsgCore
+import Testing
+@testable import imsg
+
+@Suite("RpcCommand Contacts policy")
+struct RpcCommandContactsPolicyTests {
+  @Test("headless stdin uses skipIfNotDetermined")
+  func headlessSkipsUndetermined() {
+    #expect(RpcCommand.contactsAccessPolicy(stdinIsTTY: false) == .skipIfNotDetermined)
+  }
+
+  @Test("interactive stdin keeps requestIfNeeded")
+  func interactiveRequestsIfNeeded() {
+    #expect(RpcCommand.contactsAccessPolicy(stdinIsTTY: true) == .requestIfNeeded)
+  }
+}