diff --git a/.rubocop.yml b/.rubocop.yml
index dd69bab0..83a79869 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -42,6 +42,7 @@ Naming/FileName:
   Exclude:
     - Gemfile
     - Rakefile
+    - Steepfile
 
 Layout/EndAlignment:
   EnforcedStyleAlignWith: variable
diff --git a/lib/httpx/response.rb b/lib/httpx/response.rb
index 66268177..ef30234e 100644
--- a/lib/httpx/response.rb
+++ b/lib/httpx/response.rb
@@ -173,7 +173,7 @@ module HTTPX
           rescue ArgumentError
             @buffer.string
           end
-        when Tempfile, File
+        when Tempfile
           rewind
           content = _with_same_buffer_pos { @buffer.read }
           begin
@@ -253,6 +253,7 @@ module HTTPX
             @buffer = StringIO.new("".b)
           end
         when :memory
+          # @type ivar @buffer: StringIO | Tempfile
           if @length > @threshold_size
             aux = @buffer
             @buffer = Tempfile.new("httpx", encoding: Encoding::BINARY, mode: File::RDWR)
@@ -272,11 +273,12 @@ module HTTPX
       def _with_same_buffer_pos
         return yield unless @buffer && @buffer.respond_to?(:pos)
 
+        # @type ivar @buffer: StringIO | Tempfile
         current_pos = @buffer.pos
         @buffer.rewind
         begin
           yield
-        rescue StandardError
+        ensure
           @buffer.pos = current_pos
         end
       end
diff --git a/lib/httpx/timers.rb b/lib/httpx/timers.rb
index 532a6738..213d3384 100644
--- a/lib/httpx/timers.rb
+++ b/lib/httpx/timers.rb
@@ -64,7 +64,7 @@ module HTTPX
       end
 
       def to_f
-        @interval
+        Float(@interval)
       end
 
       def <<(callback)
diff --git a/lib/httpx/transcoder/chunker.rb b/lib/httpx/transcoder/chunker.rb
index ca98076c..16618ff9 100644
--- a/lib/httpx/transcoder/chunker.rb
+++ b/lib/httpx/transcoder/chunker.rb
@@ -40,7 +40,6 @@ module HTTPX::Transcoder
 
       def initialize(buffer, trailers = false)
         @buffer = buffer
-        @chunk_length = nil
         @chunk_buffer = "".b
         @finished = false
         @state = :length
diff --git a/sig/errors.rbs b/sig/errors.rbs
index fd96899c..74c026a7 100644
--- a/sig/errors.rbs
+++ b/sig/errors.rbs
@@ -26,6 +26,14 @@ module HTTPX
   class ResolveError < Error
   end
 
+  class HTTPError < Error
+    attr_reader response: Response
+
+    private
+
+    def initialize: (Response response) -> void
+  end
+
   class NativeResolveError < ResolveError
     attr_reader connection: Connection
     attr_reader host: String
diff --git a/sig/parser/http1.rbs b/sig/parser/http1.rbs
index d666ff57..37deccab 100644
--- a/sig/parser/http1.rbs
+++ b/sig/parser/http1.rbs
@@ -1,5 +1,8 @@
 module HTTPX
   module Parser
+    class Error < HTTPX::Error
+    end
+
     type parsed_headers = Hash[String, Array[String]]
 
     interface _HTTP1Events
@@ -14,16 +17,22 @@ module HTTPX
     class HTTP1
       VERSIONS: Array[String]
 
+      attr_reader status_code: Integer
+      attr_reader http_version: [Integer, Integer]
+      attr_reader headers: parsed_headers
+
+      @observer: _HTTP1Events
+      @state: Symbol
+      @buffer: String
+      @content_type: String?
+      @content_length: Integer
+      @_has_trailers: bool
+      @upgrade: bool
+
       def <<: (String chunk) -> void
 
-      def headers: () -> parsed_headers
-
-      def http_version: () -> Array[1 | 0]
-
       def reset!: () -> void
 
-      def status_code: () -> Integer
-
       def upgrade?: () -> bool
 
       def upgrade_data: () -> String
diff --git a/sig/registry.rbs b/sig/registry.rbs
index 2148a916..0b4a6adc 100644
--- a/sig/registry.rbs
+++ b/sig/registry.rbs
@@ -1,4 +1,7 @@
 module HTTPX::Registry[T, V]
+  class Error < HTTPX::Error
+  end
+
   # type registrable = Symbol | String | Class
 
   def self.registry: (T tag) -> Class
diff --git a/sig/request.rbs b/sig/request.rbs
index 65ccff1f..1c1f30aa 100644
--- a/sig/request.rbs
+++ b/sig/request.rbs
@@ -15,6 +15,11 @@ module HTTPX
     attr_reader response: response?
     attr_reader drain_error: StandardError?
 
+    @trailers: Headers?
+    @informational_status: Integer?
+    @query: String?
+    @drainer: Enumerator[String, void]?
+
     def initialize: (Symbol | String, generic_uri, ?options) -> untyped
 
     def interests: () -> (:r | :w)
@@ -46,6 +51,10 @@ module HTTPX
     def trailers?: () -> boolish
 
     class Body
+      @headers: Headers
+      @body: body_encoder?
+      @unbounded_body: bool
+
       def initialize: (Headers, Options) -> untyped
       def each: () { (String) -> void } -> void
               | () -> Enumerable[String]
@@ -61,6 +70,8 @@ module HTTPX
     end
 
     class ProcIO
+      @block: ^(String) -> void
+
       def initialize: (^(String) -> void) -> untyped
 
       def write: (String data) -> Integer
diff --git a/sig/resolver.rbs b/sig/resolver.rbs
index 5e16273b..c54f18e1 100644
--- a/sig/resolver.rbs
+++ b/sig/resolver.rbs
@@ -2,12 +2,11 @@ module HTTPX
   type ipaddr = IPAddr | String
 
   module Resolver
+    extend Registry[Symbol, Class]
+
     RESOLVE_TIMEOUT: Integer | Float
 
-    def self.registry: (Symbol tag) -> Class
-    | () -> Hash[Symbol, Class]
-
-    def self.register: (Symbol tag,  Class handler) -> void
+    @lookup_mutex: Thread::Mutex
 
     type dns_resource = singleton(Resolv::DNS::Resource)
 
diff --git a/sig/response.rbs b/sig/response.rbs
index 235e7bba..712e0262 100644
--- a/sig/response.rbs
+++ b/sig/response.rbs
@@ -19,6 +19,7 @@ module HTTPX
 
     @options: Options
     @request: Request
+    @content_type: ContentType
 
     def copy_to: (_ToPath | _Writer destination) -> void
     def close: () -> void
@@ -45,9 +46,15 @@ module HTTPX
       include _ToS
       include _ToStr
 
+      @response: Response
+      @headers: Headers
+      @options: Options
       @state: :idle | :memory | :buffer | :closed
       @threshold_size: Integer
       @window_size: Integer
+      @encoding: String
+      @length: Integer
+      @buffer: StringIO | Tempfile | nil
 
       def write:(String chunk) -> Integer?
 
@@ -65,6 +72,7 @@ module HTTPX
       def initialize: (Response, Options) -> untyped
       def rewind: () -> void
       def transition: () -> void
+      def _with_same_buffer_pos: [A] () { () -> A } -> A
     end
   end
 
@@ -72,12 +80,13 @@ module HTTPX
     MIME_TYPE_RE: Regexp
     CHARSET_RE: Regexp
 
-    attr_reader mime_type: String?
-    attr_reader charset: String?
+    @header_value: String?
+    @mime_type: String?
+    @charset: String?
 
-    def self.parse: (_ToS) -> ContentType
-    def self.mime_type: (_ToS) -> String?
-    def self.charset: (_ToS) -> String?
+    def mime_type: () -> String?
+
+    def charset: () -> String?
 
     private
 
@@ -89,6 +98,7 @@ module HTTPX
     include Loggable
 
     @options: Options
+    @error: Exception
 
     attr_reader request: Request
 
diff --git a/sig/timers.rbs b/sig/timers.rbs
index 77a0598f..ed98fb1e 100644
--- a/sig/timers.rbs
+++ b/sig/timers.rbs
@@ -1,12 +1,13 @@
 module HTTPX
   class Timers
-    @interval: Array[Interval]
+    @intervals: Array[Interval]
+    @next_interval_at: Numeric
 
     def after: (Numeric interval_in_secs) { () -> void } -> void
 
     def wait_interval: () -> Numeric?
 
-    def fire: (?StandardError error) -> void
+    def fire: (?TimeoutError error) -> void
 
     def cancel: () -> void
 
@@ -19,6 +20,8 @@ module HTTPX
 
       attr_reader interval: Numeric
 
+      @callbacks: Array[^() -> void]
+
       def to_f: () -> Float
 
       def <<: (^() -> void) -> void
diff --git a/sig/transcoder.rbs b/sig/transcoder.rbs
index d40aad5e..087de6d5 100644
--- a/sig/transcoder.rbs
+++ b/sig/transcoder.rbs
@@ -1,6 +1,8 @@
 module HTTPX
   type bodyIO = _Reader | _Each[[String, untyped]] | _ToS
 
+  type body_encoder = Transcoder::_Encoder | _Each[String]
+
   module Transcoder
     def self?.registry: (String tag) -> _Encode
                    | () -> Hash[String, _Encode]
@@ -12,7 +14,7 @@ module HTTPX
     def self?.normalize_query: (Hash[String, untyped] params, String name, String v, Integer depth) -> void
 
     interface _Encode
-      def encode: (untyped payload) -> (_Encoder | _Each[String])
+      def encode: (untyped payload) -> body_encoder
     end
 
     interface _Encoder
diff --git a/sig/transcoder/chunker.rbs b/sig/transcoder/chunker.rbs
index c94da421..f148d7ea 100644
--- a/sig/transcoder/chunker.rbs
+++ b/sig/transcoder/chunker.rbs
@@ -10,27 +10,38 @@ module HTTPX::Transcoder
     class Encoder
       @raw: _Each[String]
 
-      include _Each[String]
+      def each: () { (String) -> void } -> void
+              | () -> Enumerator[String, void]
 
       private
 
-      def initialize: (_Each[String] chunks) -> untyped
+      def initialize: (_Each[String] chunks) -> void
     end
 
     class Decoder
       extend Forwardable
       include _ToS
-      include _Each[String]
+
+      @buffer: String
+      @chunk_length: Integer
+      @chunk_buffer: String
+      @finished: bool
+      @state: Symbol
+      @trailers: bool
+
+      def each: () { (String) -> void } -> void
 
       def finished?: () -> bool
+
       def empty?: () -> bool
+
       def <<: (string) -> void
+
       def clear: () -> void
 
       private
 
-      def initialize: (String, bool) -> untyped
-                    | (String) -> untyped
+      def initialize: (String, ?bool) -> void
 
       def nextstate: (Symbol) -> void
     end
diff --git a/sig/transcoder/json.rbs b/sig/transcoder/json.rbs
index 27fbe209..a53ccf7a 100644
--- a/sig/transcoder/json.rbs
+++ b/sig/transcoder/json.rbs
@@ -1,5 +1,7 @@
 module HTTPX::Transcoder
   module JSON
+    JSON_REGEX: Regexp
+
     def self?.encode: (_ToJson json) -> Encoder
     def self?.decode: (HTTPX::Response response) -> _Decoder
 
@@ -8,6 +10,9 @@ module HTTPX::Transcoder
       include _Encoder
       include _ToS
 
+      @raw: String
+      @charset: String
+
       def content_type: () -> String
 
       private