diff --git a/AGENTS.md b/AGENTS.md
index 5b458d3..071d772 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -99,7 +99,8 @@
 - When creating a pull request from a worktree-specific development branch, create a dedicated pull-request branch
   separate from the branch that names or anchors the worktree.
   Do not open pull requests directly from the worktree branch.
-- Ariadne uses a flat Rust source layout under `src/ariadne/`.
+- Ariadne separates Rust library code and binary entry-point code under `src/ariadne/core/` and
+  `src/ariadne/bin/`.
   Do not add a Cargo-default nested `src/ariadne/src/` source directory.
 - Use `bazel build` for non-test targets when no Bazel test target is part of the validation set.
   `bazel test` exits non-zero when it finds no test targets.
diff --git a/Cargo.lock b/Cargo.lock
index 413061d..c62239c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -10,6 +10,13 @@ dependencies = [
  "serde_json",
 ]
 
+[[package]]
+name = "ariadne-bin"
+version = "0.1.0"
+dependencies = [
+ "ariadne",
+]
+
 [[package]]
 name = "itoa"
 version = "1.0.18"
diff --git a/Cargo.toml b/Cargo.toml
index 10b9230..5b8731f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,7 @@
 [workspace]
 members = [
-    "src/ariadne",
+    "src/ariadne/bin",
+    "src/ariadne/core",
     "src/machoke",
 ]
 resolver = "3"
diff --git a/src/ariadne/BUILD b/src/ariadne/BUILD
index 273ae04..bca2a4a 100644
--- a/src/ariadne/BUILD
+++ b/src/ariadne/BUILD
@@ -1,20 +1,6 @@
-load("@rules_rust//rust:defs.bzl", "rust_binary", "rust_library")
-
-rust_library(
-    name = "ariadne_lib",
-    crate_name = "ariadne",
-    crate_root = "lib.rs",
-    srcs = [
-        "graph.rs",
-        "lib.rs",
-    ],
-)
-
-rust_binary(
+alias(
     name = "ariadne",
-    crate_name = "ariadne_cli",
-    srcs = ["main.rs"],
-    deps = [":ariadne_lib"],
+    actual = "//src/ariadne/bin:ariadne",
 )
 
 sh_binary(
diff --git a/src/ariadne/bin/BUILD b/src/ariadne/bin/BUILD
new file mode 100644
index 0000000..efa77be
--- /dev/null
+++ b/src/ariadne/bin/BUILD
@@ -0,0 +1,9 @@
+load("@rules_rust//rust:defs.bzl", "rust_binary")
+
+rust_binary(
+    name = "ariadne",
+    crate_name = "ariadne_cli",
+    visibility = ["//src/ariadne:__pkg__"],
+    srcs = ["main.rs"],
+    deps = ["//src/ariadne/core:ariadne_lib"],
+)
diff --git a/src/ariadne/bin/Cargo.toml b/src/ariadne/bin/Cargo.toml
new file mode 100644
index 0000000..18559a3
--- /dev/null
+++ b/src/ariadne/bin/Cargo.toml
@@ -0,0 +1,11 @@
+[package]
+name = "ariadne-bin"
+version = "0.1.0"
+edition = "2024"
+
+[[bin]]
+name = "ariadne"
+path = "main.rs"
+
+[dependencies]
+ariadne = { path = "../core" }
diff --git a/src/ariadne/main.rs b/src/ariadne/bin/main.rs
similarity index 100%
rename from src/ariadne/main.rs
rename to src/ariadne/bin/main.rs
diff --git a/src/ariadne/core/BUILD b/src/ariadne/core/BUILD
new file mode 100644
index 0000000..258a2b4
--- /dev/null
+++ b/src/ariadne/core/BUILD
@@ -0,0 +1,16 @@
+load("@rules_rust//rust:defs.bzl", "rust_library")
+
+rust_library(
+    name = "ariadne_lib",
+    crate_name = "ariadne",
+    crate_root = "lib.rs",
+    visibility = ["//src/ariadne:__subpackages__"],
+    srcs = [
+        "graph.rs",
+        "lib.rs",
+    ],
+    deps = [
+        "//third_party/crates:serde",
+        "//third_party/crates:serde_json",
+    ],
+)
diff --git a/src/ariadne/Cargo.toml b/src/ariadne/core/Cargo.toml
similarity index 79%
rename from src/ariadne/Cargo.toml
rename to src/ariadne/core/Cargo.toml
index 49de630..cfc2504 100644
--- a/src/ariadne/Cargo.toml
+++ b/src/ariadne/core/Cargo.toml
@@ -6,10 +6,6 @@ edition = "2024"
 [lib]
 path = "lib.rs"
 
-[[bin]]
-name = "ariadne"
-path = "main.rs"
-
 [dependencies]
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
diff --git a/src/ariadne/graph.rs b/src/ariadne/core/graph.rs
similarity index 100%
rename from src/ariadne/graph.rs
rename to src/ariadne/core/graph.rs
diff --git a/src/ariadne/lib.rs b/src/ariadne/core/lib.rs
similarity index 100%
rename from src/ariadne/lib.rs
rename to src/ariadne/core/lib.rs
diff --git a/third_party/crates/crates.bzl b/third_party/crates/crates.bzl
index 41e4c7a..d225fa8 100644
--- a/third_party/crates/crates.bzl
+++ b/third_party/crates/crates.bzl
@@ -310,12 +310,15 @@ def aliases(
 ###############################################################################
 
 _CRATE_EDITIONS = {
-    "src/ariadne": "2024",
+    "src/ariadne/bin": "2024",
+    "src/ariadne/core": "2024",
     "src/machoke": "2024",
 }
 
 _NORMAL_DEPENDENCIES = {
-    "src/ariadne": {
+    "src/ariadne/bin": {
+    },
+    "src/ariadne/core": {
         _COMMON_CONDITION: {
             "serde": Label("//third_party/crates/serde-1.0.229:serde"),
             "serde_json": Label("//third_party/crates/serde_json-1.0.151:serde_json"),
@@ -326,7 +329,9 @@ _NORMAL_DEPENDENCIES = {
 }
 
 _NORMAL_ALIASES = {
-    "src/ariadne": {
+    "src/ariadne/bin": {
+    },
+    "src/ariadne/core": {
         _COMMON_CONDITION: {
         },
     },
@@ -335,70 +340,90 @@ _NORMAL_ALIASES = {
 }
 
 _NORMAL_DEV_DEPENDENCIES = {
-    "src/ariadne": {
+    "src/ariadne/bin": {
+    },
+    "src/ariadne/core": {
     },
     "src/machoke": {
     },
 }
 
 _NORMAL_DEV_ALIASES = {
-    "src/ariadne": {
+    "src/ariadne/bin": {
+    },
+    "src/ariadne/core": {
     },
     "src/machoke": {
     },
 }
 
 _PROC_MACRO_DEPENDENCIES = {
-    "src/ariadne": {
+    "src/ariadne/bin": {
+    },
+    "src/ariadne/core": {
     },
     "src/machoke": {
     },
 }
 
 _PROC_MACRO_ALIASES = {
-    "src/ariadne": {
+    "src/ariadne/bin": {
+    },
+    "src/ariadne/core": {
     },
     "src/machoke": {
     },
 }
 
 _PROC_MACRO_DEV_DEPENDENCIES = {
-    "src/ariadne": {
+    "src/ariadne/bin": {
+    },
+    "src/ariadne/core": {
     },
     "src/machoke": {
     },
 }
 
 _PROC_MACRO_DEV_ALIASES = {
-    "src/ariadne": {
+    "src/ariadne/bin": {
+    },
+    "src/ariadne/core": {
     },
     "src/machoke": {
     },
 }
 
 _BUILD_DEPENDENCIES = {
-    "src/ariadne": {
+    "src/ariadne/bin": {
+    },
+    "src/ariadne/core": {
     },
     "src/machoke": {
     },
 }
 
 _BUILD_ALIASES = {
-    "src/ariadne": {
+    "src/ariadne/bin": {
+    },
+    "src/ariadne/core": {
     },
     "src/machoke": {
     },
 }
 
 _BUILD_PROC_MACRO_DEPENDENCIES = {
-    "src/ariadne": {
+    "src/ariadne/bin": {
+    },
+    "src/ariadne/core": {
     },
     "src/machoke": {
     },
 }
 
 _BUILD_PROC_MACRO_ALIASES = {
-    "src/ariadne": {
+    "src/ariadne/bin": {
+    },
+    "src/ariadne/core": {
     },
     "src/machoke": {
     },