diff --git a/src/discover/registry.rs b/src/discover/registry.rs
index 4fd716828..a133c4f48 100644
--- a/src/discover/registry.rs
+++ b/src/discover/registry.rs
@@ -3972,4 +3972,105 @@ mod tests {
             std::borrow::Cow::<str>::Borrowed("git diff HEAD~1"),
         );
     }
+
+    // --- PHP (#1892) ---
+
+    #[test]
+    fn test_classify_php_bare_is_passthrough() {
+        assert!(matches!(
+            classify_command("php"),
+            Classification::Supported {
+                rtk_equivalent: "rtk php",
+                estimated_savings_pct: 0.0,
+                status: RtkStatus::Passthrough,
+                ..
+            }
+        ));
+    }
+
+    #[test]
+    fn test_classify_php_artisan_is_passthrough() {
+        assert!(matches!(
+            classify_command("php artisan migrate"),
+            Classification::Supported {
+                rtk_equivalent: "rtk php",
+                estimated_savings_pct: 0.0,
+                status: RtkStatus::Passthrough,
+                ..
+            }
+        ));
+    }
+
+    #[test]
+    fn test_classify_php_script_is_passthrough() {
+        assert!(matches!(
+            classify_command("php script.php"),
+            Classification::Supported {
+                rtk_equivalent: "rtk php",
+                estimated_savings_pct: 0.0,
+                status: RtkStatus::Passthrough,
+                ..
+            }
+        ));
+    }
+
+    #[test]
+    fn test_classify_phpunit_not_php() {
+        // phpunit is a different tool (PHPUnit test runner) — must not be misclassified
+        // as the php interpreter rule (#1892 regression guard).
+        // Unsupported / Ignored are both fine — we only forbid a php-rule match.
+        if let Classification::Supported { rtk_equivalent, .. } = classify_command("phpunit tests/")
+        {
+            assert_ne!(
+                rtk_equivalent, "rtk php",
+                "phpunit must not be rewritten via the php rule"
+            );
+        }
+    }
+
+    #[test]
+    fn test_rewrite_php_bare() {
+        assert_eq!(
+            rewrite_command_no_prefixes("php", &[]),
+            Some("rtk php".into())
+        );
+    }
+
+    #[test]
+    fn test_rewrite_php_artisan_migrate() {
+        assert_eq!(
+            rewrite_command_no_prefixes("php artisan migrate", &[]),
+            Some("rtk php artisan migrate".into())
+        );
+    }
+
+    #[test]
+    fn test_rewrite_php_artisan_serve() {
+        assert_eq!(
+            rewrite_command_no_prefixes("php artisan serve", &[]),
+            Some("rtk php artisan serve".into())
+        );
+    }
+
+    #[test]
+    fn test_rewrite_php_script_file() {
+        assert_eq!(
+            rewrite_command_no_prefixes("php script.php --opt", &[]),
+            Some("rtk php script.php --opt".into())
+        );
+    }
+
+    #[test]
+    fn test_rewrite_phpunit_not_rewritten_as_php() {
+        // phpunit must NOT be rewritten to `rtk php unit` or `rtk php …`.
+        // (It may be left unchanged, or rewritten via its own future rule —
+        // but the php rule must not steal it.)
+        let result = rewrite_command_no_prefixes("phpunit tests/", &[]);
+        if let Some(ref rewritten) = result {
+            assert!(
+                !rewritten.starts_with("rtk php "),
+                "phpunit should not be rewritten via php rule, got: {rewritten}"
+            );
+        }
+    }
 }
diff --git a/src/discover/rules.rs b/src/discover/rules.rs
index df7c72d03..6fcd9ceef 100644
--- a/src/discover/rules.rs
+++ b/src/discover/rules.rs
@@ -581,6 +581,20 @@ pub const RULES: &[RtkRule] = &[
         subcmd_savings: &[],
         subcmd_status: &[],
     },
+    // PHP interpreter (artisan, scripts, -v, etc.). This is intentionally
+    // passthrough-only: there is no built-in PHP TOML/Rust filter, but routing
+    // through `rtk php` lets the hook preserve RTK history/tracking for #1892.
+    // Pattern uses a word boundary so it matches `php` and `php ...`, but never
+    // adjacent PHP tools like `phpunit`, `phpcs`, or `phpstan`.
+    RtkRule {
+        pattern: r"^(php)(?:\s|$)",
+        rtk_cmd: "rtk php",
+        rewrite_prefixes: &["php"],
+        category: "Build",
+        savings_pct: 0.0,
+        subcmd_savings: &[],
+        subcmd_status: &[("php", RtkStatus::Passthrough)],
+    },
     RtkRule {
         pattern: r"^df(\s|$)",
         rtk_cmd: "rtk df",