diff --git a/src/Framework/Framework.jl b/src/Framework/Framework.jl
index 193868c8a..a7c3979ab 100644
--- a/src/Framework/Framework.jl
+++ b/src/Framework/Framework.jl
@@ -147,18 +147,39 @@ using Crayons
 using MacroTools
 using OrderedCollections
 
+# Convenience aliases.
 argerr(m) = throw(ArgumentError(m))
 const Option{T} = Union{T,Nothing}
 struct PhantomData{T} end
+const imap = Iterators.map
+const ifilter = Iterators.filter
+
+# ==========================================================================================
+# Early small types declarations to avoid circular dependencies among code files.
 
 # Abstract over various exception thrown during inconsistent use of the system.
 abstract type SystemException <: Exception end
 
+# The parametric type 'V' for the component
+# is the type of the value wrapped by the system.
+abstract type Component{V} end
+abstract type Blueprint{V} end
+
+export Component
+export Blueprint
+
+# Most framework internals work with component types
+# because they can be abstract,
+# most exposed methods work with concrete singleton instance.
+const CompType{V} = Type{<:Component{V}}
+
+# ==========================================================================================
+
 # Base structure.
-include("./component.jl")
+include("./system.jl") #  <- Defines the 'System' type used in the next files..
+include("./component.jl") # <- But better start reading from this file.
 include("./blueprints.jl")
 include("./methods.jl")
-include("./system.jl")
 include("./add.jl")
 include("./plus_operator.jl")
 
diff --git a/src/Framework/blueprint_macro.jl b/src/Framework/blueprint_macro.jl
index 68fd96775..d7f041140 100644
--- a/src/Framework/blueprint_macro.jl
+++ b/src/Framework/blueprint_macro.jl
@@ -12,20 +12,20 @@
 # is automatically considered 'potential brought': the macro invocation makes it work.
 # The following methods are relevant then:
 #
-#   brought(::Name) = generated iterator over the fields, skipping 'nothing' values.
-#   implied_blueprint_for(::Name, ::Type{CompType}) = <assumed implemented by macro invoker>
+#   brought(::Blueprint) = generated iterator over the fields, skipping 'nothing' values.
+#   implied_blueprint_for(::Blueprint, ::Type{CompType}) = <assumed implemented by macro invoker>
 #
 # And for blueprint user convenience, override:
 #
-#   setproperty!(::Name, field, value)
+#   setproperty!(::Blueprint, field, value)
 #
 # When given `nothing` as a value, void the field.
 # When given a blueprint, check its provided components for consistency then embed.
 # When given a comptype or a singleton component instance, make it implied.
 # When given anything else, query the following for a callable blueprint constructor:
 #
-#   constructor_for_embedded(::Name, ::Val{fieldname}) = Component
-#   # (default, not reified/overrideable yet)
+#   constructor_for_embedded(::Blueprint, ::Val{fieldname}) = Component
+#   # (defaults to the provided component if single, not reified/overrideable yet)
 #
 # then pass whatever value to this constructor to get this sugar:
 #
@@ -241,7 +241,7 @@ function blueprint_macro(__module__, __source__, input...)
                         )
                     bp
                 end
-                setfield!(b, prop, val)
+                setfield!(b, prop, BroughtField{expected_C, ValueType}(val))
             end
         end,
     )
diff --git a/src/Framework/blueprints.jl b/src/Framework/blueprints.jl
index 78e51f5ff..4212b7c22 100644
--- a/src/Framework/blueprints.jl
+++ b/src/Framework/blueprints.jl
@@ -32,9 +32,6 @@
 # This blueprint requirement is specified by the 'expands_from' function.
 # Expanding-from an abstract component A is expanding from any component subtyping A.
 
-abstract type Blueprint{V} end
-export Blueprint
-
 # Every blueprint provides only concrete components, and at least one.
 struct UnspecifiedComponents{B<:Blueprint} end
 componentsof(::B) where {B<:Blueprint} = throw(UnspecifiedComponents{B}())
diff --git a/src/Framework/component.jl b/src/Framework/component.jl
index b54f8c812..737897dcf 100644
--- a/src/Framework/component.jl
+++ b/src/Framework/component.jl
@@ -32,16 +32,8 @@
 # This might be implemented in the future for a convincingly motivated need,
 # at the cost of extending @component macro to produce abstract types.
 
-# The parametric type 'V' for the component
-# is the type of the value wrapped by the system.
-abstract type Component{V} end
-export Component
-
-# Most framework internals work with component types
-# because they can be abstract,
-# most exposed methods work with concrete singleton instance.
-const CompType{V} = Type{<:Component{V}}
-Base.convert(::CompType{V}, c::Component{V}) where {V} = typeof(c) # Singleton ergonomy.
+# Singleton component ergonomy.
+Base.convert(::CompType{V}, c::Component{V}) where {V} = typeof(c)
 
 # Component types being singleton, we *can* infer the value from the type at runtime.
 singleton_instance(C::CompType) = throw("No concrete singleton instance of '$C'.")
diff --git a/src/Framework/method_macro.jl b/src/Framework/method_macro.jl
index 46185476d..f9baa6ed8 100644
--- a/src/Framework/method_macro.jl
+++ b/src/Framework/method_macro.jl
@@ -359,23 +359,6 @@ function method_macro(__module__, __source__, input...)
         Framework.depends(::Type{ValueType}, ::Type{typeof(fn)}) = deps
     end)
 
-    # Generate the method checking that required components
-    # are loaded on the system instance.
-    push_res!(
-        quote
-            function Framework.missing_dependency_for(
-                ::Type{ValueType},
-                M::Type{typeof(fn)},
-                s::System,
-            )
-                for dep in depends(ValueType, M)
-                    has_component(s, dep) || return dep
-                end
-                nothing
-            end
-        end,
-    )
-
     # Override the detected methods with checked code receiving system values.
     efn = LOCAL_MACROCALLS ? esc(fn_xp) : Meta.quot(:($__module__.$fn_xp))
     fn_path = Meta.quot(Meta.quot(fn_xp))
@@ -388,7 +371,7 @@ function method_macro(__module__, __source__, input...)
                 xp = quote
                     function $($efn)(; kwargs...)
                         #  function $mod.$fnname(; kwargs...)
-                        $dep = missing_dependency_for($ValueType, $($efn), $receiver)
+                        $dep = missing_dependency_for($($efn), $receiver)
                         if !isnothing($dep)
                             $a = isabstracttype($dep) ? " a" : ""
                             throw(
diff --git a/src/Framework/methods.jl b/src/Framework/methods.jl
index 113a7328a..631dc70e6 100644
--- a/src/Framework/methods.jl
+++ b/src/Framework/methods.jl
@@ -36,12 +36,23 @@
 # The wrapped system value type must always be specified.
 
 # Methods depend on nothing by default.
-depends(V::Type, ::Type{<:Function}) = CompType{V}[]
-missing_dependency_for(::Type, ::Type{<:Function}, _) = nothing
+depends(::Type{V}, ::Type{<:Function}) where {V} = CompType{V}[]
+missing_dependencies_for(fn::Type{<:Function}, s::System{V}) where {V} =
+    Iterators.filter(depends(V, fn)) do dep
+        !has_component(s, dep)
+    end
+# Just pick the first one. Return nothing if dependencies are met.
+function missing_dependency_for(fn::Type{<:Function}, s::System)
+    for dep in missing_dependencies_for(fn, s)
+        return dep
+    end
+    nothing
+end
 
 # Direct call with the functions themselves.
-depends(V::Type, fn::Function) = depends(V, typeof(fn))
-missing_dependency_for(V::Type, fn::Function, s) = missing_dependency_for(V, typeof(fn), s)
+depends(::Type{V}, fn::Function) where {V} = depends(V, typeof(fn))
+missing_dependencies_for(fn::Function, s::System) = missing_dependencies_for(typeof(fn), s)
+missing_dependency_for(fn::Function, s::System) = missing_dependency_for(typeof(fn), s)
 
 # Map wrapped system value and property name to the corresponding function.
 read_property(V::Type, ::Val{name}) where {name} =
diff --git a/src/Framework/system.jl b/src/Framework/system.jl
index 4ff17f81f..60ac0a0ed 100644
--- a/src/Framework/system.jl
+++ b/src/Framework/system.jl
@@ -73,9 +73,9 @@ function Base.getproperty(system::System{V}, p::Symbol) where {V}
     # Search property method.
     fn = read_property(V, Val(p))
     # Check for required components availability.
-    Miss = missing_dependency_for(V, fn, system)
-    if !isnothing(Miss)
-        comp = isabstracttype(Miss) ? "A component $Miss" : "Component $Miss"
+    miss = missing_dependency_for(fn, system)
+    if !isnothing(miss)
+        comp = isabstracttype(miss) ? "A component $miss" : "Component $miss"
         properr(V, p, "$comp is required to read this property.")
     end
     # Forward to method.
@@ -88,9 +88,9 @@ function Base.setproperty!(system::System{V}, p::Symbol, rhs) where {V}
     # Search property method.
     fn = readwrite_property(V, Val(p))
     # Check for required components availability.
-    Miss = missing_dependency_for(V, fn, system)
-    if !isnothing(Miss)
-        comp = isabstracttype(Miss) ? "A component $Miss" : "Component $Miss"
+    miss = missing_dependency_for(fn, system)
+    if !isnothing(miss)
+        comp = isabstracttype(miss) ? "A component $miss" : "Component $miss"
         properr(V, p, "$comp is required to write to this property.")
     end
     # Invoke property method.
@@ -119,8 +119,8 @@ end
 # Query components.
 
 # Iterate over all concrete components.
-component_types(s::System) = Iterators.map(identity, s._concrete)
-components(s::System) = Iterators.map(singleton_instance, component_types(s))
+component_types(s::System) = imap(identity, s._concrete)
+components(s::System) = imap(singleton_instance, component_types(s))
 # Restrict to the given component (super)type.
 components_types(system::System{V}, C::CompType{V}) where {V} =
     if isabstracttype(C)
@@ -131,7 +131,7 @@ components_types(system::System{V}, C::CompType{V}) where {V} =
         C in d ? (C,) : ()
     end
 components(s::System, C::CompType{V}) where {V} =
-    Iterators.map(singleton_instance, components_types(s, C))
+    imap(singleton_instance, components_types(s, C))
 export components, component_types
 
 # Basic check.
@@ -141,10 +141,11 @@ has_concrete_component(s::System{V}, c::Component{V}) where {V} = typeof(c) in s
 export has_component, has_concrete_component
 
 # List all properties and associated functions for this type.
-# Yields (name, fn_read, Option{fn_write}) values.
+# Yields (property_name, fn_read, Option{fn_write}, iterator{dependencies...}).
 function properties(::Type{V}) where {V}
-    Iterators.map(
-        Iterators.filter(methods(read_property, Tuple{Type{V},Val}, Framework)) do mth
+    imap(
+        ifilter(methods(read_property, Tuple{Type{V},Val}, Framework)) do mth
+            mth.sig isa UnionAll && return false # Only consider concrete implementations.
             val = mth.sig.types[end]
             val <: Val ||
                 throw("Unexpected method signature for $read_property: $(mth.sig)")
@@ -153,27 +154,39 @@ function properties(::Type{V}) where {V}
     ) do mth
         val = mth.sig.types[end]
         name = first(val.parameters)
-        (name, read_property(V, Val(name)), possible_write_property(V, Val(name)))
+        read_fn = read_property(V, Val(name))
+        write_fn = possible_write_property(V, Val(name))
+        (name, read_fn, write_fn, imap(identity, depends(V, read_fn)))
     end
 end
+# Also feature for system type directly.
+properties(::Type{System{V}}) where {V} = properties(V)
+export properties
 
-# List properties available for this system type.
-# Returns {:propname => is_writeable}
-function properties(::Type{System{V}}) where {V}
-    Dict(p => isnothing(write) for (p, read, write) in properties(V))
+# List properties available for *this* particular instance.
+# Yields (:propname, read, Option{write})
+function properties(s::System{V}) where {V}
+    imap(ifilter(properties(V)) do (_, read, _, _)
+        isnothing(missing_dependency_for(read, s))
+    end) do (name, read, write, _)
+        (name, read, write)
+    end
 end
 
-# List properties available for this instance.
-function properties(s::System{V}) where {V}
-    Dict(
-        p => isnothing(write) for
-        (p, read, write) in properties(V) if isnothing(missing_dependency_for(V, read, s))
-    )
+# List *unavailable* properties for this instance
+# along with the components missing to support them.
+# Yields (:propname, read, Option{write}, iterator{missing_dependencies...})
+function latent_properties(s::System{V}) where {V}
+    imap(ifilter(properties(V)) do (_, read, _, _)
+        !isnothing(missing_dependency_for(read, s))
+    end) do (name, read, write, deps)
+        (name, read, write, ifilter(d -> !has_component(s, d), deps))
+    end
 end
-export properties
+export latent_properties
 
 # Consistency + REPL completion.
-Base.propertynames(s::System{V}) where {V} = collect(keys(properties(s)))
+Base.propertynames(s::System) = imap(first, properties(s))
 
 #-------------------------------------------------------------------------------------------
 
diff --git a/test/framework/01-regular_use.jl b/test/framework/01-regular_use.jl
index 031c669b6..7ad5b3185 100644
--- a/test/framework/01-regular_use.jl
+++ b/test/framework/01-regular_use.jl
@@ -279,6 +279,33 @@ end
     sr = sa + ReflectFromB()
     @test sr.reflection == collect("12321")
 
+    #---------------------------------------------------------------------------------------
+    # List properties.
+
+    # All possible system properties and their dependencies.
+    props = properties(typeof(sa))
+    @test sort(map(((n, r, w, g),) -> (n, r, w, F.singleton_instance.(g)), props)) == [
+        (:a, get_a, nothing, Component[A]),
+        (:b, get_b, nothing, Component[B]),
+        (:n, get_n, nothing, Component[Size]),
+        (:ref, get_reflection, set_reflection!, Component[Reflection]),
+        (:reflection, get_reflection, set_reflection!, Component[Reflection]),
+        (:sum, get_sum, nothing, Component[A, B]),
+    ]
+
+    # Only the ones available on this instance.
+    props = properties(sa)
+    @test sort(collect(props)) == [(:a, get_a, nothing), (:n, get_n, nothing)]
+
+    # Only the ones *missing* on this instance.
+    props = latent_properties(sa)
+    @test sort(map(((n, r, w, g),) -> (n, r, w, F.singleton_instance.(g)), props)) == [
+        (:b, get_b, nothing, Component[B]),
+        (:ref, get_reflection, set_reflection!, Component[Reflection]),
+        (:reflection, get_reflection, set_reflection!, Component[Reflection]),
+        (:sum, get_sum, nothing, Component[B]),
+    ]
+
 end
 
 # ==========================================================================================
@@ -323,7 +350,7 @@ end
     # Embedded blueprints.
 
     # Explicitly bring it instead of implying.
-    a.size = NLines(2) # HERE: check Base.setproperty! definition in blueprint_macro.jl.
+    a.size = NLines(2)
 
     # The component is also brought.
     s = e + a
@@ -346,7 +373,7 @@ end
 
     # And it is an error to bring it if the component is already there.
     s = e + NLines(2) # (*even* if the data are consistent)
-    @sysfails(s += a, Add(BroughtAlreadyInValue, [NLines, false, A.Raw]))
+    @sysfails(s += a, Add(BroughtAlreadyInValue, Size, [NLines, false, A.Raw]))
 
     #---------------------------------------------------------------------------------------
     # Unbrought blueprints.
@@ -355,7 +382,7 @@ end
     a.size = nothing
 
     # The component is not brought then.
-    @sysfails(e + a, Add(MissingRequiredComponent, Size, [A.Raw], nothing, false))
+    @sysfails(e + a, Add(MissingRequiredComponent, A, Size, [A.Raw], nothing))
 
 end
 
diff --git a/test/framework/runtests.jl b/test/framework/runtests.jl
index 858997c0c..d243ef338 100644
--- a/test/framework/runtests.jl
+++ b/test/framework/runtests.jl
@@ -7,6 +7,7 @@ Framework.LOCAL_MACROCALLS = true
 # Run all numbered -.jl files we can find by default, except the current one.
 only = [
     "./01-regular_use.jl",
+    #  "./02-blueprints.jl",
 ] # Unless some files are specified here, in which case only run these.
 if isempty(only)
     for (folder, _, files) in walkdir(dirname(@__FILE__))
@@ -26,4 +27,6 @@ else
     end
 end
 
+Framework.LOCAL_MACROCALLS = false
+
 end