diff --git a/crates/hi-agent/src/steering/implementation.rs b/crates/hi-agent/src/steering/implementation.rs
index cf3387b2..e06c0426 100644
--- a/crates/hi-agent/src/steering/implementation.rs
+++ b/crates/hi-agent/src/steering/implementation.rs
@@ -182,8 +182,8 @@ fn tool_result_is_failure(output: &str) -> bool {
     let trimmed = output.trim_start();
     trimmed.starts_with("Error:")
         || trimmed.starts_with("⚠ refused:")
-        || trimmed.contains("[exit code ")
-        || trimmed.contains("[timed out")
+        || trimmed.contains(hi_tools::markers::EXIT_CODE_PREFIX)
+        || trimmed.contains(hi_tools::markers::TIMED_OUT_PREFIX)
 }
 
 fn filesystem_mutation_result_landed(name: &str, output: &str) -> bool {
diff --git a/crates/hi-tools/src/lib.rs b/crates/hi-tools/src/lib.rs
index 5225a724..59624cf6 100644
--- a/crates/hi-tools/src/lib.rs
+++ b/crates/hi-tools/src/lib.rs
@@ -140,6 +140,31 @@ pub enum TruncationState {
     },
 }
 
+/// Model-facing tool-result markers. Steering (hi-agent) string-matches on
+/// these, so emitters and matchers must share one definition — a matcher
+/// drifting from the emitted text is exactly the bug class that left the
+/// timed-out matcher dead ("[timed out after " vs the emitted string).
+/// Tests deliberately keep verbatim literals as canaries: changing a marker
+/// must be a conscious, test-breaking decision.
+pub mod markers {
+    /// Fallback for an empty result whose status carries no exit code.
+    pub const NO_OUTPUT: &str = "[no output]";
+    /// Empty stdout+stderr on a successful command.
+    pub const NO_OUTPUT_SUCCESS: &str = "[no output — command succeeded (exit 0)]";
+    /// Successful command whose only output went to stderr.
+    pub const STDERR_ONLY_SUCCESS: &str = "[command succeeded (exit 0) — output above is stderr]";
+    /// Prefix of every failure exit-code annotation. Success annotations must
+    /// never contain it — steering classifies on this prefix.
+    pub const EXIT_CODE_PREFIX: &str = "[exit code ";
+    /// Prefix shared by all timeout annotations.
+    pub const TIMED_OUT_PREFIX: &str = "[timed out";
+    /// The full timeout annotation.
+    pub const TIMED_OUT_KILLED: &str = "[timed out — process killed]";
+    /// Just-in-time reminder appended to successful commands containing `cd`.
+    pub const CWD_RESET_NOTE: &str =
+        "[note: the working directory resets to the workspace root before the next command]";
+}
+
 /// The result of a tool call, split into `content` shown to the model and an
 /// optional richer `display` for the UI (e.g. a colored diff). This keeps
 /// edit/write feedback terse for the model while showing the user what changed.
diff --git a/crates/hi-tools/src/process.rs b/crates/hi-tools/src/process.rs
index 65fdbb03..1aa6759e 100644
--- a/crates/hi-tools/src/process.rs
+++ b/crates/hi-tools/src/process.rs
@@ -62,10 +62,11 @@ impl ProcessExecution {
                     }
                     if stdout_empty && stderr_empty {
                         out.push_str(&format!(
-                            "[exit code {code} — no output on stdout or stderr]"
+                            "{}{code} — no output on stdout or stderr]",
+                            crate::markers::EXIT_CODE_PREFIX
                         ));
                     } else {
-                        out.push_str(&format!("[exit code {code}]"));
+                        out.push_str(&format!("{}{code}]", crate::markers::EXIT_CODE_PREFIX));
                     }
                 }
             }
@@ -73,25 +74,25 @@ impl ProcessExecution {
                 if !out.is_empty() && !out.ends_with('\n') {
                     out.push('\n');
                 }
-                out.push_str("[timed out — process killed]");
+                out.push_str(crate::markers::TIMED_OUT_KILLED);
             }
             // Empty and stderr-only results are where models form false
             // premises ("did it work?" / "stderr means it failed") — state
             // the verdict explicitly instead of leaving it implied.
             ToolStatus::Succeeded => {
                 if stdout_empty && stderr_empty {
-                    out.push_str("[no output — command succeeded (exit 0)]");
+                    out.push_str(crate::markers::NO_OUTPUT_SUCCESS);
                 } else if stdout_empty {
                     if !out.ends_with('\n') {
                         out.push('\n');
                     }
-                    out.push_str("[command succeeded (exit 0) — output above is stderr]");
+                    out.push_str(crate::markers::STDERR_ONLY_SUCCESS);
                 }
             }
             _ => {}
         }
         if out.is_empty() {
-            out.push_str("[no output]");
+            out.push_str(crate::markers::NO_OUTPUT);
         }
         out
     }
diff --git a/crates/hi-tools/src/tools.rs b/crates/hi-tools/src/tools.rs
index ff76629c..91ad3d86 100644
--- a/crates/hi-tools/src/tools.rs
+++ b/crates/hi-tools/src/tools.rs
@@ -1982,10 +1982,7 @@ async fn run_bash_tool(
                 if !content.ends_with('\n') {
                     content.push('\n');
                 }
-                content.push_str(
-                    "[note: the working directory resets to the workspace root before the \
-                     next command]",
-                );
+                content.push_str(crate::markers::CWD_RESET_NOTE);
             }
             let mut outcome = ToolOutcome::plain(content);
             outcome.status = execution.status;