Main now runs Steep, so the sources, sync and new model columns get
signatures. The JSON columns are parsed by hand: Sequel's serialization
plugin passes json 3.1 a create_additions option it no longer accepts.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LG4iASZnHb1yEM1JAASiWn

diff --git a/Steepfile b/Steepfile
index ae41aec..5f3fdfb 100644
--- a/Steepfile
+++ b/Steepfile
@@ -11,4 +11,5 @@ target :lib do
   signature "sig"
 
   library "securerandom"
+  library "json"
 end
diff --git a/lib/rank_king/models.rb b/lib/rank_king/models.rb
index 14fc9bb..8cad246 100644
--- a/lib/rank_king/models.rb
+++ b/lib/rank_king/models.rb
@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require "json"
+
 require_relative "db"
 require_relative "sources"
 
@@ -13,14 +15,22 @@ module RankKing
     one_to_many :items, class: "RankKing::Item", conditions: { archived_at: nil }
     one_to_many :axes, class: "RankKing::Axis"
 
-    plugin :serialization, :json, :source_config
+    def source_config = JSON.parse(super)
+    def source_config=(value)
+      super(JSON.generate(value))
+    end
 
     def source = Sources.fetch(source_kind).new(source_config)
   end
 
   # @rbs skip
   class Item < Sequel::Model(DB[:items])
-    plugin :serialization, :json, :metadata
+    # JSON by hand rather than Sequel's serialization plugin, which passes
+    # json 3.1 an option it no longer takes.
+    def metadata = JSON.parse(super)
+    def metadata=(value)
+      super(JSON.generate(value))
+    end
 
     many_to_one :list, class: "RankKing::List"
   end
diff --git a/lib/rank_king/sources.rb b/lib/rank_king/sources.rb
index 9e65d66..f728529 100644
--- a/lib/rank_king/sources.rb
+++ b/lib/rank_king/sources.rb
@@ -4,11 +4,9 @@ module RankKing
   module Sources
     # What every source produces: one entry per item currently in the source.
     # external_id is how sync recognizes the same item across snapshots.
-    Entry = Data.define(:external_id, :name, :url, :metadata) do
-      def initialize(external_id:, name:, url: nil, metadata: {})
-        super
-      end
-    end
+    # Signed in sig/rank_king/sources.rbs: a Data class.
+    # @rbs skip
+    Entry = Data.define(:external_id, :name, :url, :metadata)
   end
 end
 
@@ -18,8 +16,9 @@ module RankKing
   module Sources
     ALL = {
       Text.kind => Text,
-    }.freeze
+    }.freeze #: Hash[String, _SourceClass]
 
+    #: (String kind) -> _SourceClass
     def self.fetch(kind) = ALL.fetch(kind)
   end
 end
diff --git a/lib/rank_king/sources/text.rb b/lib/rank_king/sources/text.rb
index 875136a..8f274a6 100644
--- a/lib/rank_king/sources/text.rb
+++ b/lib/rank_king/sources/text.rb
@@ -4,16 +4,23 @@ module RankKing
   module Sources
     # A push source: the snapshot is pasted text, one item per line.
     class Text
+      # @rbs @config: Hash[String, untyped]
+
+      #: () -> String
       def self.kind = "text"
+
+      #: () -> bool
       def self.push? = true
 
+      #: (?Hash[String, untyped] config) -> void
       def initialize(config = {})
         @config = config
       end
 
+      #: (untyped snapshot) -> Array[Entry]
       def entries(snapshot)
         snapshot.to_s.lines.map(&:strip).reject(&:empty?).uniq.map {|line|
-          Entry.new(external_id: line, name: line)
+          Entry.new(external_id: line, name: line, url: nil, metadata: {})
         }
       end
     end
diff --git a/lib/rank_king/sync.rb b/lib/rank_king/sync.rb
index 9aa76f7..344fb8c 100644
--- a/lib/rank_king/sync.rb
+++ b/lib/rank_king/sync.rb
@@ -8,8 +8,11 @@ module RankKing
   # so their results survive, and come back with their history if they
   # reappear.
   module Sync
+    # Signed in sig/rank_king/sync.rbs: a Data class.
+    # @rbs skip
     Summary = Data.define(:added, :restored, :archived)
 
+    #: (List list, Array[Sources::Entry] entries, ?now: Time) -> Summary
     def self.call(list, entries, now: Time.now)
       DB.transaction do
         existing = Item.where(list_id: list.id).exclude(external_id: nil).to_hash(:external_id)
@@ -19,9 +22,9 @@ module RankKing
           attrs = { name: entry.name, url: entry.url, metadata: entry.metadata, archived_at: nil }
           if (item = existing.delete(entry.external_id))
             restored += 1 if item.archived_at
-            item.update(attrs)
+            item.update(**attrs)
           else
-            Item.create(attrs.merge(list_id: list.id, external_id: entry.external_id))
+            Item.create(**attrs, list_id: list.id, external_id: entry.external_id)
             added += 1
           end
         end
diff --git a/sig/gems/sequel.rbs b/sig/gems/sequel.rbs
index 54ae822..fcb1bec 100644
--- a/sig/gems/sequel.rbs
+++ b/sig/gems/sequel.rbs
@@ -25,11 +25,16 @@ module Sequel
   class Dataset[out T]
     def where: (*untyped conditions) -> Dataset[T]
 
+    def exclude: (*untyped conditions) -> Dataset[T]
+
+    # Rows keyed by one column's value.
+    def to_hash: (Symbol key) -> Hash[untyped, T]
+
     def first: () -> T?
   end
 
   class Model
-    def self.plugin: (Symbol name, **untyped options) -> void
+    def self.plugin: (Symbol name, *untyped args, **untyped options) -> void
 
     def self.one_to_many: (Symbol name, **untyped options) -> void
 
@@ -39,10 +44,15 @@ module Sequel
 
     def self.all: () -> Array[instance]
 
+    def self.where: (*untyped conditions) -> Dataset[instance]
+
     # The row with this primary key, or nil.
     def self.[]: (untyped id) -> instance?
 
     def id: () -> Integer
+
+    # Sets the columns given and saves the row.
+    def update: (**untyped values) -> self
   end
 
   # Applies the migrations in a directory that the database has not run
diff --git a/sig/rank_king/models.rbs b/sig/rank_king/models.rbs
index 4c373f5..68b688f 100644
--- a/sig/rank_king/models.rbs
+++ b/sig/rank_king/models.rbs
@@ -8,12 +8,22 @@ module RankKing
     def axes: () -> Array[Axis]
     def items_dataset: () -> Sequel::Dataset[Item]
     def axes_dataset: () -> Sequel::Dataset[Axis]
+    def source_kind: () -> String
+    def source_config: () -> Hash[String, untyped]
+    def source_config=: (Hash[String, untyped] value) -> void
+    def synced_at: () -> Time?
+    def source: () -> Sources::_Source
   end
 
   class Item < Sequel::Model
     def name: () -> String
     def list_id: () -> Integer
     def list: () -> List
+    def external_id: () -> String?
+    def url: () -> String?
+    def metadata: () -> Hash[String, untyped]
+    def metadata=: (Hash[String, untyped] value) -> void
+    def archived_at: () -> Time?
   end
 
   class Axis < Sequel::Model
diff --git a/sig/rank_king/sources.rbs b/sig/rank_king/sources.rbs
new file mode 100644
index 0000000..f389c79
--- /dev/null
+++ b/sig/rank_king/sources.rbs
@@ -0,0 +1,28 @@
+# Entry is a Data class, whose members the inline parser cannot read, and
+# the interfaces every source kind meets are named here so Sources::ALL
+# and List#source can be typed by them.
+module RankKing
+  module Sources
+    class Entry
+      attr_reader external_id: String
+      attr_reader name: String
+      attr_reader url: String?
+      attr_reader metadata: Hash[String, untyped]
+
+      def self.new: (external_id: String, name: String, url: String?, metadata: Hash[String, untyped]) -> instance
+    end
+
+    # A source instance: turns a snapshot (the pasted text for a push
+    # source, ignored by a pull source) into entries.
+    interface _Source
+      def entries: (untyped snapshot) -> Array[Entry]
+    end
+
+    # A source kind, the class registered in Sources::ALL.
+    interface _SourceClass
+      def kind: () -> String
+      def push?: () -> bool
+      def new: (Hash[String, untyped] config) -> _Source
+    end
+  end
+end
diff --git a/sig/rank_king/sync.rbs b/sig/rank_king/sync.rbs
new file mode 100644
index 0000000..798b1e6
--- /dev/null
+++ b/sig/rank_king/sync.rbs
@@ -0,0 +1,12 @@
+# Summary is a Data class, whose members the inline parser cannot read.
+module RankKing
+  module Sync
+    class Summary
+      attr_reader added: Integer
+      attr_reader restored: Integer
+      attr_reader archived: Integer
+
+      def self.new: (added: Integer, restored: Integer, archived: Integer) -> instance
+    end
+  end
+end
diff --git a/test/test_sync.rb b/test/test_sync.rb
index 571a8e6..2801442 100644
--- a/test/test_sync.rb
+++ b/test/test_sync.rb
@@ -47,7 +47,7 @@ class TestSync < Minitest::Test
   end
 
   def test_refreshes_name_url_and_metadata
-    Sync.call(@list, [Sources::Entry.new(external_id: "v1", name: "Old")])
+    Sync.call(@list, [Sources::Entry.new(external_id: "v1", name: "Old", url: nil, metadata: {})])
     Sync.call(@list, [Sources::Entry.new(external_id: "v1", name: "New", url: "https://example.com/v1", metadata: { "thumb" => "t.jpg" })])
 
     item = Item.first(external_id: "v1")