diff --git a/zig/src/server/cli.zig b/zig/src/server/cli.zig
index 0e2da51172..d36a933aa7 100644
--- a/zig/src/server/cli.zig
+++ b/zig/src/server/cli.zig
@@ -571,17 +571,8 @@ pub fn request(a: Allocator, dir: []const u8, model_type: []const u8, args: Args
     });
 }
 
-/// What ``capabilities --json`` reports about the engine side: its version, chip, backends and families.
-pub const Engines = struct {
-    version: []const u8,
-    chip: ?[]const u8 = null,
-    optional_libraries: []const @import("sys").optional_libraries.Status = &.{},
-    backends: []const []const u8 = &.{},
-    /// model_type to the weight formats it reads, as gate entries name them.
-    families: []const api.Family = &.{},
-};
-
-/// The native capabilities document: the table's native flags and the honoured variables.
+/// ``capabilities --json`` (cli_capabilities.zig): the engine side, then the table's native flags and variables.
+pub const Engines = @import("cli_capabilities.zig").Engines;
 pub const capabilities = @import("cli_capabilities.zig").capabilities;
 
 const cli = @This();
diff --git a/zig/src/server/cli_capabilities.zig b/zig/src/server/cli_capabilities.zig
index 7ee1fd2283..4c5d8607d1 100644
--- a/zig/src/server/cli_capabilities.zig
+++ b/zig/src/server/cli_capabilities.zig
@@ -1,8 +1,20 @@
-//! The native capabilities document: the table's native flags and the honoured variables.
+//! ``capabilities --json``: the engine's version, chip, backends and families, then the native flags and variables.
 const std = @import("std");
+const api = @import("engine_api");
 const cli = @import("cli.zig");
 
-pub fn capabilities(w: *std.Io.Writer, e: cli.Engines) !void {
+/// What ``capabilities --json`` reports about the engine side: its version, chip, backends and families.
+pub const Engines = struct {
+    version: []const u8,
+    chip: ?[]const u8 = null,
+    optional_libraries: []const @import("sys").optional_libraries.Status = &.{},
+    backends: []const []const u8 = &.{},
+    /// model_type to the weight formats it reads, as gate entries name them.
+    families: []const api.Family = &.{},
+};
+
+/// The native capabilities document: the table's native flags and the honoured variables.
+pub fn capabilities(w: *std.Io.Writer, e: Engines) !void {
     try w.print("{{\"schema\": 1, \"engine\": \"zig\", \"version\": \"{s}\", \"chip\": ", .{e.version});
     if (e.chip) |c| try w.print("\"{s}\"", .{c}) else try w.writeAll("null");
     try w.writeAll(", \"backends\": [");