diff --git a/crates/mind-body/tests/self_run.rs b/crates/mind-body/tests/self_run.rs
index ddfc2f1..98f014f 100644
--- a/crates/mind-body/tests/self_run.rs
+++ b/crates/mind-body/tests/self_run.rs
@@ -46,6 +46,44 @@ fn the_run_cap_must_be_a_positive_number_of_seconds_and_the_runtime_directory_mu
     assert!(!message.contains("MIND_SELF_RUN_CAP_S") && message.contains("RUNTIME_DIRECTORY is not set"), "{message}");
 }
 
+/// The hook `claude` runs in the session: `mind-self-run inject --spool <dir>` reads the hook's
+/// JSON on stdin and prints what the spool holds as context, exit 0; with `--pre-compact` it
+/// blocks the compaction with exit 2; without a spool it is a usage error.
+#[test]
+fn inject_prints_the_spooled_briefs_as_hook_context_and_blocks_a_compaction() {
+    use std::io::Write;
+    use std::process::Stdio;
+    let spool = std::env::temp_dir().join(format!("mind-self-run-inject-{}", std::process::id()));
+    std::fs::create_dir_all(&spool).unwrap();
+    std::fs::write(
+        spool.join("00000000000000000007-b7.json"),
+        r#"{"id":"eureka-body:follow_up:b7","campaign":"eureka-body","repo":"GameCult/Huginn","item":"Wire the thing.","ordinal":7}"#,
+    )
+    .unwrap();
+    let inject = |extra: &[&str], input: &str| {
+        let mut child = Command::new(env!("CARGO_BIN_EXE_mind-self-run"))
+            .args(["inject", "--spool", spool.to_str().unwrap()])
+            .args(extra)
+            .stdin(Stdio::piped())
+            .stdout(Stdio::piped())
+            .stderr(Stdio::piped())
+            .spawn()
+            .unwrap();
+        child.stdin.take().unwrap().write_all(input.as_bytes()).unwrap();
+        child.wait_with_output().unwrap()
+    };
+    let blocked = inject(&["--pre-compact"], "{}");
+    assert_eq!((blocked.status.code(), blocked.stdout.is_empty()), (Some(2), true));
+    let printed = inject(&[], r#"{"hook_event_name":"PostToolBatch"}"#);
+    assert_eq!(printed.status.code(), Some(0));
+    let text = String::from_utf8_lossy(&printed.stdout);
+    assert!(text.contains("hookSpecificOutput") && text.contains("eureka-body:follow_up:b7") && text.contains("Wire the thing."), "{text}");
+    assert!(inject(&[], "{}").stdout.is_empty(), "claimed once");
+    let bare = Command::new(env!("CARGO_BIN_EXE_mind-self-run")).arg("inject").stdin(Stdio::null()).output().unwrap();
+    assert_eq!(bare.status.code(), Some(2));
+    std::fs::remove_dir_all(&spool).unwrap();
+}
+
 #[test]
 fn without_an_instance_or_with_a_stray_argument_it_exits_2_with_the_usage_and_echoes_nothing() {
     let canary = "canary-argument-3f9a";
@@ -321,7 +359,7 @@ mod lane {
         let body = format!(
             "read -r -u \"$CLAUDE_CODE_OAUTH_TOKEN_FILE_DESCRIPTOR\" cred
 echo journal-line >&2
-echo '{first}'\necho '{second}'\nread -t 5 start\nread -t 5 flush\necho \"$start\" >> {record}\necho \"$flush\" >> {record}\necho \"$SELF_RUN_ENV_CANARY\" >> {record}\necho \"$cred\" >> {record}\necho '{{\"type\":\"result\"}}'\nwhile read more; do :; done\nexit 0",
+echo '{first}'\necho '{second}'\nread -t 5 start\nread -t 5 flush\necho \"$start\" >> {record}\necho \"$flush\" >> {record}\necho \"$SELF_RUN_ENV_CANARY\" >> {record}\necho \"$cred\" >> {record}\necho '{{\"type\":\"result\"}}'\necho '{{\"type\":\"result\"}}'\nwhile read more; do :; done\nexit 0",
             first = request("msg_1", 100),
             second = request("msg_2", 299_999),
             record = bin.path().join("record").display(),
@@ -333,7 +371,8 @@ echo '{first}'\necho '{second}'\nread -t 5 start\nread -t 5 flush\necho \"$start
 
         let stdout = String::from_utf8_lossy(&output.stdout).to_string();
         assert_eq!(output.status.code(), Some(0), "{stdout}\n{}", String::from_utf8_lossy(&output.stderr));
-        assert_eq!(stdout, "request 1 prefix 101\nrequest 2 prefix 300000\nended: flush-requested code 0 requests 2 prefix 300000\n");
+        let printed: String = stdout.lines().filter(|line| !line.starts_with("decision ") && !line.starts_with("result")).map(|line| format!("{line}\n")).collect();
+        assert_eq!(printed, "request 1 prefix 101\nrequest 2 prefix 300000\nended: flush-requested code 0 requests 2 prefix 300000\n");
         assert!(!all_output(&output).contains(ENV_CANARY), "the unit environment is not echoed");
         assert!(String::from_utf8_lossy(&output.stderr).contains("journal-line"), "the child's stderr is the unit's journal");