diff --git a/scripts/api_client.gd b/scripts/api_client.gd
index d5961a7..6182f3a 100644
--- a/scripts/api_client.gd
+++ b/scripts/api_client.gd
@@ -456,6 +456,31 @@ func report_message(message_id: int, conversation_type: String, reason: String,
 	return await SocialApiClient.report_message(self, message_id, conversation_type, reason, context_text)
 
 
+# ---------------------------------------------------------------------------
+# Discovery Features
+# ---------------------------------------------------------------------------
+
+## List public worlds for discovery with optional search, tags, category, and sort.
+func get_discovery_worlds(
+	q: String = "",
+	tags: Array = [],
+	category: String = "",
+	sort: String = "newest",
+	skip: int = 0,
+	limit: int = 50
+) -> Dictionary:
+	return await DiscoveryApiClient.get_worlds(self, q, tags, category, sort, skip, limit)
+
+## Get distinct categories of public worlds.
+func get_discovery_categories() -> Dictionary:
+	return await DiscoveryApiClient.get_categories(self)
+
+## Record a visit to a world.
+func record_world_visit(world_id: int, anonymous_token: String = "") -> Dictionary:
+	return await DiscoveryApiClient.record_visit(self, world_id, anonymous_token)
+
+
+
 
 # ---------------------------------------------------------------------------
 # Internals
diff --git a/scripts/discovery_api_client.gd b/scripts/discovery_api_client.gd
new file mode 100644
index 0000000..4c331d9
--- /dev/null
+++ b/scripts/discovery_api_client.gd
@@ -0,0 +1,140 @@
+extends RefCounted
+class_name DiscoveryApiClient
+## Helper client for AGP Discovery REST endpoints (Browse, Search, Categories, Visit tracking).
+##
+## docs/planning/discovery.md (task 56c49440d0a6).
+
+class WorldSummary extends RefCounted:
+	var id: int = 0
+	var name: String = ""
+	var description: String = ""
+	var category: String = ""
+	var tags: Array = []
+	var play_count: int = 0
+	var created_at: String = ""
+	var owner_id: int = 0
+	var owner_username: String = ""
+
+	static func from_dict(d: Dictionary) -> WorldSummary:
+		var w := WorldSummary.new()
+		w.id = int(d.get("id", 0))
+		w.name = str(d.get("name", ""))
+		w.description = str(d.get("description", "")) if d.get("description") != null else ""
+		w.category = str(d.get("category", "")) if d.get("category") != null else ""
+		var raw_tags = d.get("tags", [])
+		w.tags = raw_tags if raw_tags is Array else []
+		w.play_count = int(d.get("play_count", 0))
+		w.created_at = str(d.get("created_at", "")) if d.get("created_at") != null else ""
+		var owner: Dictionary = d.get("owner", {}) if d.get("owner") is Dictionary else {}
+		w.owner_id = int(owner.get("id", 0))
+		w.owner_username = str(owner.get("username", ""))
+		return w
+
+
+class DiscoveryResult extends RefCounted:
+	var items: Array[WorldSummary] = []
+	var total: int = 0
+	var skip: int = 0
+	var limit: int = 50
+
+	static func from_dict(d: Dictionary) -> DiscoveryResult:
+		var res := DiscoveryResult.new()
+		res.total = int(d.get("total", 0))
+		res.skip = int(d.get("skip", 0))
+		res.limit = int(d.get("limit", 50))
+		var raw_items = d.get("items", [])
+		if raw_items is Array:
+			for item in raw_items:
+				if item is Dictionary:
+					res.items.append(WorldSummary.from_dict(item))
+		return res
+
+
+static func get_api_client(node: Node) -> Node:
+	if node.has_node("/root/ApiClient"):
+		return node.get_node("/root/ApiClient")
+	return null
+
+
+## Fetch worlds with search, tags, category filter, sort, and pagination.
+## Attaches JWT token if client has one; works anonymously without token.
+## Surfaces transport/HTTP errors in the standard result dictionary.
+static func get_worlds(
+	api: Node,
+	q: String = "",
+	tags: Array = [],
+	category: String = "",
+	sort: String = "newest",
+	skip: int = 0,
+	limit: int = 50
+) -> Dictionary:
+	var params: Array[String] = []
+	if q != "":
+		params.append("q=" + q.uri_encode())
+	if tags.size() > 0:
+		var tag_strs: Array[String] = []
+		for t in tags:
+			tag_strs.append(str(t))
+		params.append("tags=" + ",".join(tag_strs).uri_encode())
+	if category != "":
+		params.append("category=" + category.uri_encode())
+	if sort != "":
+		params.append("sort=" + sort.uri_encode())
+	params.append("skip=%d" % skip)
+	params.append("limit=%d" % limit)
+
+	var url := "/api/discovery/worlds"
+	if params.size() > 0:
+		url += "?" + "&".join(params)
+
+	var custom_headers := PackedStringArray()
+	if api != null and api.has_method("has_token") and api.has_token():
+		custom_headers.append("Authorization: " + api.bearer_token)
+
+	var res: Dictionary = await api.request(
+		HTTPClient.METHOD_GET,
+		url,
+		"",
+		"application/json",
+		false,
+		custom_headers
+	)
+	if res.ok and res.data is Dictionary:
+		res["parsed"] = DiscoveryResult.from_dict(res.data)
+	return res
+
+
+## Fetch distinct categories of public worlds.
+static func get_categories(api: Node) -> Dictionary:
+	var custom_headers := PackedStringArray()
+	if api != null and api.has_method("has_token") and api.has_token():
+		custom_headers.append("Authorization: " + api.bearer_token)
+
+	return await api.request(
+		HTTPClient.METHOD_GET,
+		"/api/discovery/categories",
+		"",
+		"application/json",
+		false,
+		custom_headers
+	)
+
+
+## Record a visit to a world. Supports optional anonymous token or logged in user.
+static func record_visit(api: Node, world_id: int, anonymous_token: String = "") -> Dictionary:
+	var custom_headers := PackedStringArray()
+	if api != null and api.has_method("has_token") and api.has_token():
+		custom_headers.append("Authorization: " + api.bearer_token)
+
+	var payload := {}
+	if anonymous_token != "":
+		payload["anonymous_token"] = anonymous_token
+
+	return await api.request(
+		HTTPClient.METHOD_POST,
+		"/api/discovery/worlds/%d/visit" % world_id,
+		JSON.stringify(payload) if payload.size() > 0 else "",
+		"application/json",
+		false,
+		custom_headers
+	)
diff --git a/scripts/smoke_test_discovery_client.gd b/scripts/smoke_test_discovery_client.gd
new file mode 100644
index 0000000..d1f7ba1
--- /dev/null
+++ b/scripts/smoke_test_discovery_client.gd
@@ -0,0 +1,62 @@
+extends SceneTree
+## Headless smoke test for DiscoveryApiClient.
+
+func _init() -> void:
+	print("[SMOKE] Starting DiscoveryApiClient smoke test...")
+
+	# 1. Test WorldSummary parsing
+	var test_dict := {
+		"id": 42,
+		"name": "Neon Arcade",
+		"description": "Retro gaming lounge",
+		"category": "Arcade",
+		"tags": ["retro", "multiplayer"],
+		"play_count": 128,
+		"created_at": "2026-09-15T12:00:00Z",
+		"owner": {
+			"id": 7,
+			"username": "arcadegamer"
+		}
+	}
+
+	var summary := DiscoveryApiClient.WorldSummary.from_dict(test_dict)
+	assert(summary.id == 42, "summary id mismatch")
+	assert(summary.name == "Neon Arcade", "summary name mismatch")
+	assert(summary.category == "Arcade", "summary category mismatch")
+	assert(summary.tags.size() == 2, "summary tags size mismatch")
+	assert(summary.play_count == 128, "summary play_count mismatch")
+	assert(summary.owner_id == 7, "summary owner_id mismatch")
+	assert(summary.owner_username == "arcadegamer", "summary owner_username mismatch")
+	print("[PASS] WorldSummary parsing verified")
+
+	# 2. Test DiscoveryResult parsing
+	var page_dict := {
+		"items": [test_dict],
+		"total": 1,
+		"skip": 0,
+		"limit": 50
+	}
+	var res := DiscoveryApiClient.DiscoveryResult.from_dict(page_dict)
+	assert(res.total == 1, "res total mismatch")
+	assert(res.items.size() == 1, "res items size mismatch")
+	assert(res.items[0].id == 42, "res items[0] id mismatch")
+	print("[PASS] DiscoveryResult parsing verified")
+
+	# 3. Test ApiClient integration
+	var api_script = load("res://scripts/api_client.gd")
+	if not api_script:
+		printerr("[FAIL] Could not load api_client.gd")
+		quit(1)
+		return
+
+	var api: Node = api_script.new()
+	root.add_child(api)
+
+	assert(api.has_method("get_discovery_worlds"), "Missing get_discovery_worlds on ApiClient")
+	assert(api.has_method("get_discovery_categories"), "Missing get_discovery_categories on ApiClient")
+	assert(api.has_method("record_world_visit"), "Missing record_world_visit on ApiClient")
+	print("[PASS] ApiClient discovery methods verified")
+
+	api.queue_free()
+	print("[SMOKE] DiscoveryApiClient smoke test PASSED")
+	quit(0)