diff --git a/README.md b/README.md
index 5481d6b..247d77d 100644
--- a/README.md
+++ b/README.md
@@ -12,7 +12,8 @@ Runtime debugging for AI agents, and for people. An app built with Crafter.Debug
 Breakpoints and memory stay with a debugger; `crafter-debug debugger` prints how to attach one.
 
 ```console
-$ crafter-build --debug-api -r &              # the app's debug build, in the background
+$ crafter-build --debug-api                   # the app's debug build, and the client with it
+$ crafter-build --debug-api -r &              # the app, in the background
 $ ./build/crafter-debug ls --wait 60s
 game  id 4f1c09a2b7e3d851  pid 3 (sandbox 48211)  up 4s  port 41207
 $ ./build/crafter-debug call Lobby_Start && ./build/crafter-debug wait --frames 30
diff --git a/examples/Basic/implementations/Basic.World.cpp b/examples/Basic/implementations/Basic.World.cpp
index 14459f5..eb27403 100644
--- a/examples/Basic/implementations/Basic.World.cpp
+++ b/examples/Basic/implementations/Basic.World.cpp
@@ -16,6 +16,7 @@ void Basic::World::Reset() {
 
 void Basic::World::Clear() {
     balls.clear();
+    nextId = 1;
     time = 0;
     fastest = 0;
 }
diff --git a/examples/Basic/interfaces/Basic.World.cppm b/examples/Basic/interfaces/Basic.World.cppm
index 3ec2b06..892f5c7 100644
--- a/examples/Basic/interfaces/Basic.World.cppm
+++ b/examples/Basic/interfaces/Basic.World.cppm
@@ -43,8 +43,9 @@ export namespace Basic {
         Physics physics;
         Floor floor;
 
-        // Removes every ball and drops the scene's five.
+        // Removes every ball and drops the scene's five, as balls 1 to 5.
         void Reset();
+        // Removes every ball; ids start again from 1.
         void Clear();
         // Returns the new ball's id.
         std::int32_t Spawn(float x, float y, float vy, float radius);
diff --git a/implementations/Crafter.Debug.Cli-Client.cpp b/implementations/Crafter.Debug.Cli-Client.cpp
index 3cbb467..bc4d041 100644
--- a/implementations/Crafter.Debug.Cli-Client.cpp
+++ b/implementations/Crafter.Debug.Cli-Client.cpp
@@ -974,13 +974,15 @@ memory are a debugger's job; `crafter-debug debugger` prints how to attach one.
 
 ## The loop
 
-1. Build and start the app from its debug build, in the background (it does
-   not exit): `crafter-build --debug-api -r` (use the project's own flag).
-2. `./build/crafter-debug ls --wait 60s` until it is listed.
-3. `cmds` and `help <command>` to see what it offers, `get '*'` for its state.
-4. Act and observe: `call`, `set`, `pause --when`, `wait`, `step`, `trace`,
+1. Build with the debug flag, in the foreground: `crafter-build --debug-api`
+   (use the project's own flag). That build compiles this client too.
+2. Start the app in the background, since it does not exit:
+   `crafter-build --debug-api -r`.
+3. `./build/crafter-debug ls --wait 60s` until it is listed.
+4. `cmds` and `help <command>` to see what it offers, `get '*'` for its state.
+5. Act and observe: `call`, `set`, `pause --when`, `wait`, `step`, `trace`,
    `log --level warn`, `screenshot` (open the PNG it prints with Read).
-5. `quit` when done. Killing the background task may leave the app running
+6. `quit` when done. Killing the background task may leave the app running
    if crafter-build's alias lacks --die-with-parent; `ls` shows leftovers.
 
 ## Commands
diff --git a/tooling/AGENTS.consumer.md b/tooling/AGENTS.consumer.md
index 3d4e544..f44536b 100644
--- a/tooling/AGENTS.consumer.md
+++ b/tooling/AGENTS.consumer.md
@@ -4,7 +4,8 @@ This app can be driven while it runs: call its commands, read and set its state,
 
 ### Driving it
 
-- Start the debug build in the background, since it does not exit: `crafter-build <debug flag> -r`.
+- Build with the debug flag first, in the foreground: `crafter-build <debug flag>`. That build also compiles the client `./build/crafter-debug` runs. The first one takes a few minutes.
+- Then start the app in the background, since it does not exit: `crafter-build <debug flag> -r`.
 - From the project directory, use `./build/crafter-debug`:
   - `ls --wait 60s` until it is listed; `status`, `cmds`, `help <command>`, `get '*'`
   - `call <command> key=value ...`, `set <path> <value>`
diff --git a/tooling/interfaces/Crafter.Debug.Build.cppm b/tooling/interfaces/Crafter.Debug.Build.cppm
index 0c2aee6..00b8b43 100644
--- a/tooling/interfaces/Crafter.Debug.Build.cppm
+++ b/tooling/interfaces/Crafter.Debug.Build.cppm
@@ -87,7 +87,7 @@ namespace Crafter::Debug {
             "# project with {0}: runs the crafter-debug client that build compiled.\n"
             "client={1}\n"
             "if [ ! -x \"$client\" ]; then\n"
-            "    echo \"crafter-debug: the client is not built yet; build with: crafter-build {0}\" >&2\n"
+            "    echo \"crafter-debug: the client is not built yet; let crafter-build {0} finish first, which builds it with the app\" >&2\n"
             "    exit 2\n"
             "fi\n",
             flag, ShellQuote(client.string()));
@@ -113,7 +113,7 @@ namespace Crafter::Debug {
         return std::format(
             "#!/bin/sh\n"
             "# Written by Crafter.Debug (Debug::Use): this project has no debug build yet.\n"
-            "echo \"crafter-debug: no debug build yet; build with: crafter-build {}\" >&2\n"
+            "echo \"crafter-debug: no debug build yet; build with: crafter-build {0}, then start the app in the background with: crafter-build {0} -r\" >&2\n"
             "exit 2\n",
             flag);
     }