diff --git a/src/core/rules.c b/src/core/rules.c
index 7201584..a739c56 100644
--- a/src/core/rules.c
+++ b/src/core/rules.c
@@ -1,5 +1,9 @@
 #include "core/rules.h"
 
+#include <stddef.h>
+#include <string.h>
+#include <zdwm/types.h>
+
 #include "base/memory.h"
 #include "core/types.h"
 
@@ -35,3 +39,43 @@ void rules_cleanup(rules_t *rules) {
   rules->capacity = 0;
   rules->count = 0;
 }
+
+static inline bool str_match(const char *pattern, const char *value) {
+  return !pattern || (value && strcmp(pattern, value) == 0);
+}
+
+static bool rule_match_window(const rule_match_t *match,
+                              const window_metadata_t *meta) {
+  return str_match(match->app_id, meta->app_id) &&
+         str_match(match->role, meta->role) &&
+         str_match(match->class_name, meta->class_name) &&
+         str_match(match->instance_name, meta->instance_name);
+}
+
+static void rule_action_merge(const rule_action_t *src, rule_action_t *dest) {
+  if (!src || !dest) return;
+
+  if (src->workspace != ZDWM_WORKSPACE_ID_INVALID) {
+    dest->workspace = src->workspace;
+  }
+  dest->switch_to_workspace |= src->switch_to_workspace;
+  dest->fullscreen |= src->fullscreen;
+  dest->maximize |= src->maximize;
+  dest->floating |= src->floating;
+}
+
+bool rules_resolve(const rules_t *rules, const window_metadata_t *metadata,
+                   rule_action_t *action_out) {
+  if (!action_out) return false;
+
+  bool matched = false;
+
+  for (size_t i = 0; i < rules->count; ++i) {
+    if (!rule_match_window(&rules->items[i].match, metadata)) continue;
+
+    matched = true;
+    rule_action_merge(&rules->items[i].action, action_out);
+  }
+
+  return matched;
+}
diff --git a/src/core/rules.h b/src/core/rules.h
index d26e4ae..de9a6a7 100644
--- a/src/core/rules.h
+++ b/src/core/rules.h
@@ -3,6 +3,7 @@
 #include <stddef.h>
 
 #include "core/types.h"
+#include "core/window.h"
 
 typedef struct rule_item_t {
   rule_match_t match;
@@ -17,3 +18,6 @@ typedef struct rules_t {
 
 bool rules_move(rules_t *src, rules_t *dest);
 void rules_cleanup(rules_t *rules);
+
+bool rules_resolve(const rules_t *rules, const window_metadata_t *metadata,
+                   rule_action_t *action_out);