diff --git a/src/ModelingToolkit.jl b/src/ModelingToolkit.jl
index d0f427bd14..992690cfe0 100644
--- a/src/ModelingToolkit.jl
+++ b/src/ModelingToolkit.jl
@@ -142,6 +142,7 @@ function var_derivative_graph! end
 include("bipartite_graph.jl")
 using .BipartiteGraphs
 
+export EvalAt
 include("variables.jl")
 include("parameters.jl")
 include("independent_variables.jl")
diff --git a/src/systems/diffeqs/odesystem.jl b/src/systems/diffeqs/odesystem.jl
index 01b0ca5fbb..50655d0074 100644
--- a/src/systems/diffeqs/odesystem.jl
+++ b/src/systems/diffeqs/odesystem.jl
@@ -247,7 +247,7 @@ end
 function ODESystem(deqs::AbstractVector{<:Equation}, iv, dvs, ps;
         controls = Num[],
         observed = Equation[],
-        constraintsystem = nothing,
+        constraints = Any[],
         costs = Num[],
         consolidate = nothing,
         systems = ODESystem[],
@@ -276,11 +276,29 @@ function ODESystem(deqs::AbstractVector{<:Equation}, iv, dvs, ps;
     name === nothing &&
         throw(ArgumentError("The `name` keyword must be provided. Please consider using the `@named` macro"))
     @assert all(control -> any(isequal.(control, ps)), controls) "All controls must also be parameters."
+
+    constraintsystem = nothing
+    if !isempty(constraints)
+        constraintsystem = process_constraint_system(constraints, dvs, ps, iv)
+        for p in parameters(constraintsystem)
+            !in(p, Set(ps)) && push!(ps, p)
+        end
+    end
+
+    if !isempty(costs)
+        coststs, costps = process_costs(costs, dvs, ps, iv)
+        for p in costps
+            !in(p, Set(ps)) && push!(ps, p)
+        end
+    end
+    costs = wrap.(costs)
+
     iv′ = value(iv)
     ps′ = value.(ps)
     ctrl′ = value.(controls)
     dvs′ = value.(dvs)
     dvs′ = filter(x -> !isdelay(x, iv), dvs′)
+
     parameter_dependencies, ps′ = process_parameter_dependencies(
         parameter_dependencies, ps′)
     if !(isempty(default_u0) && isempty(default_p))
@@ -350,7 +368,7 @@ function ODESystem(deqs::AbstractVector{<:Equation}, iv, dvs, ps;
         metadata, gui_metadata, is_dde, tstops, checks = checks)
 end
 
-function ODESystem(eqs, iv; constraints = Equation[], costs = Num[], kwargs...)
+function ODESystem(eqs, iv; kwargs...)
     diffvars, allunknowns, ps, eqs = process_equations(eqs, iv)
 
     for eq in get(kwargs, :parameter_dependencies, Equation[])
@@ -382,30 +400,8 @@ function ODESystem(eqs, iv; constraints = Equation[], costs = Num[], kwargs...)
     end
     algevars = setdiff(allunknowns, diffvars)
 
-    consvars = OrderedSet()
-    constraintsystem = nothing
-    if !isempty(constraints)
-        constraintsystem = process_constraint_system(constraints, allunknowns, new_ps, iv)
-        for st in get_unknowns(constraintsystem)
-            iscall(st) ?
-            !in(operation(st)(iv), allunknowns) && push!(consvars, st) :
-            !in(st, allunknowns) && push!(consvars, st)
-        end
-        for p in parameters(constraintsystem)
-            !in(p, new_ps) && push!(new_ps, p)
-        end
-    end
-
-    if !isempty(costs)
-        coststs, costps = process_costs(costs, allunknowns, new_ps, iv)
-        for p in costps
-            !in(p, new_ps) && push!(new_ps, p)
-        end
-    end
-    costs = wrap.(costs)
-
-    return ODESystem(eqs, iv, collect(Iterators.flatten((diffvars, algevars, consvars))),
-        collect(new_ps); constraintsystem, costs, kwargs...)
+    return ODESystem(eqs, iv, collect(Iterators.flatten((diffvars, algevars))),
+        collect(new_ps); kwargs...)
 end
 
 # NOTE: equality does not check cached Jacobian
@@ -760,7 +756,7 @@ end
 Build the constraint system for the ODESystem.
 """
 function process_constraint_system(
-        constraints::Vector{Equation}, sts, ps, iv; consname = :cons)
+        constraints::Vector, sts, ps, iv; consname = :cons)
     isempty(constraints) && return nothing
 
     constraintsts = OrderedSet()
@@ -800,7 +796,7 @@ Return the set of additional parameters found in the system, e.g. in x(p) ~ 3 th
 parameter of the system.
 """
 function validate_vars_and_find_ps!(auxvars, auxps, sysvars, iv)
-    sts = sysvars
+    sts = Set(sysvars)
 
     for var in auxvars
         if !iscall(var)
diff --git a/src/systems/discrete_system/discrete_system.jl b/src/systems/discrete_system/discrete_system.jl
index 5f7c986659..075aa27e4d 100644
--- a/src/systems/discrete_system/discrete_system.jl
+++ b/src/systems/discrete_system/discrete_system.jl
@@ -121,7 +121,7 @@ struct DiscreteSystem <: AbstractDiscreteSystem
             tearing_state = nothing, substitutions = nothing, namespacing = true,
             complete = false, index_cache = nothing, parent = nothing,
             isscheduled = false;
-            checks::Union{Bool, Int} = true)
+            checks::Union{Bool, Int} = true, kwargs...)
         if checks == true || (checks & CheckComponents) > 0
             check_independent_variables([iv])
             check_variables(dvs, iv)
@@ -199,7 +199,7 @@ function DiscreteSystem(eqs::AbstractVector{<:Equation}, iv, dvs, ps;
     DiscreteSystem(Threads.atomic_add!(SYSTEM_COUNT, UInt(1)),
         eqs, iv′, dvs′, ps′, tspan, var_to_name, observed, name, description, systems,
         defaults, guesses, initializesystem, initialization_eqs, preface, connector_type,
-        parameter_dependencies, metadata, gui_metadata, kwargs...)
+        parameter_dependencies, metadata, gui_metadata)
 end
 
 function DiscreteSystem(eqs, iv; kwargs...)
diff --git a/src/systems/model_parsing.jl b/src/systems/model_parsing.jl
index 195b02118e..024c249363 100644
--- a/src/systems/model_parsing.jl
+++ b/src/systems/model_parsing.jl
@@ -65,6 +65,8 @@ function _model_macro(mod, fullname::Union{Expr, Symbol}, expr, isconnector)
     ps, sps, vs, = [], [], []
     c_evts = []
     d_evts = []
+    cons = []
+    costs = []
     kwargs = OrderedCollections.OrderedSet()
     where_types = Union{Symbol, Expr}[]
 
@@ -80,7 +82,7 @@ function _model_macro(mod, fullname::Union{Expr, Symbol}, expr, isconnector)
     for arg in expr.args
         if arg.head == :macrocall
             parse_model!(exprs.args, comps, ext, eqs, icon, vs, ps,
-                sps, c_evts, d_evts, dict, mod, arg, kwargs, where_types)
+                sps, c_evts, d_evts, cons, costs, dict, mod, arg, kwargs, where_types)
         elseif arg.head == :block
             push!(exprs.args, arg)
         elseif arg.head == :if
@@ -120,13 +122,15 @@ function _model_macro(mod, fullname::Union{Expr, Symbol}, expr, isconnector)
     gui_metadata = isassigned(icon) > 0 ? GUIMetadata(GlobalRef(mod, name), icon[]) :
                    GUIMetadata(GlobalRef(mod, name))
 
+    consolidate = get(dict, :consolidate, nothing)
     description = get(dict, :description, "")
 
     @inline pop_structure_dict!.(
         Ref(dict), [:constants, :defaults, :kwargs, :structural_parameters])
 
     sys = :($type($(flatten_equations)(equations), $iv, variables, parameters;
-        name, description = $description, systems, gui_metadata = $gui_metadata, defaults))
+        name, description = $description, systems, gui_metadata = $gui_metadata, defaults,
+        costs = [$(costs...)], constraints = [$(cons...)], consolidate = $consolidate))
 
     if length(ext) == 0
         push!(exprs.args, :(var"#___sys___" = $sys))
@@ -610,7 +614,7 @@ function get_var(mod::Module, b)
 end
 
 function parse_model!(exprs, comps, ext, eqs, icon, vs, ps, sps, c_evts, d_evts,
-        dict, mod, arg, kwargs, where_types)
+        cons, costs, dict, mod, arg, kwargs, where_types)
     mname = arg.args[1]
     body = arg.args[end]
     if mname == Symbol("@description")
@@ -638,6 +642,12 @@ function parse_model!(exprs, comps, ext, eqs, icon, vs, ps, sps, c_evts, d_evts,
         parse_icon!(body, dict, icon, mod)
     elseif mname == Symbol("@defaults")
         parse_system_defaults!(exprs, arg, dict)
+    elseif mname == Symbol("@constraints")
+        parse_costs!(cons, dict, body)
+    elseif mname == Symbol("@costs")
+        parse_constraints!(costs, dict, body)
+    elseif mname == Symbol("@consolidate")
+        parse_consolidate!(body, dict)
     else
         error("$mname is not handled.")
     end
@@ -1149,6 +1159,32 @@ function parse_discrete_events!(d_evts, dict, body)
     end
 end
 
+function parse_constraints!(cons, dict, body)
+    dict[:constraints] = []
+    Base.remove_linenums!(body)
+    for arg in body.args
+        push!(cons, arg)
+        push!(dict[:constraints], readable_code.(cons)...)
+    end
+end
+
+function parse_costs!(costs, dict, body)
+    dict[:costs] = []
+    Base.remove_linenums!(body)
+    for arg in body.args
+        push!(costs, arg)
+        push!(dict[:costs], readable_code.(costs)...)
+    end
+end
+
+function parse_consolidate!(body, dict)
+    if !(occursin("->", string(body)) || occursin("=", string(body)))
+        error("Consolidate must be a function definition.")
+    else
+        dict[:consolidate] = body
+    end
+end
+
 function parse_icon!(body::String, dict, icon, mod)
     icon_dir = get(ENV, "MTK_ICONS_DIR", joinpath(DEPOT_PATH[1], "mtk_icons"))
     dict[:icon] = icon[] = if isfile(body)
diff --git a/src/systems/unit_check.jl b/src/systems/unit_check.jl
index 5035a22b5e..83a5ac5483 100644
--- a/src/systems/unit_check.jl
+++ b/src/systems/unit_check.jl
@@ -272,7 +272,7 @@ function validate(jumps::ArrayPartition{<:Union{Any, Vector{<:JumpType}}}, t::Sy
     all([validate(jumps.x[idx], t, info = labels[idx]) for idx in 1:3])
 end
 
-function validate(eq::Equation; info::String = "")
+function validate(eq::Union{Inequality, Equation}; info::String = "")
     if typeof(eq.lhs) == Connection
         _validate(eq.rhs; info)
     else
diff --git a/src/variables.jl b/src/variables.jl
index f3dd16819d..83e72cea35 100644
--- a/src/variables.jl
+++ b/src/variables.jl
@@ -612,3 +612,43 @@ getunshifted(x::Symbolic) = Symbolics.getmetadata(x, VariableUnshifted, nothing)
 
 getshift(x::Num) = getshift(unwrap(x))
 getshift(x::Symbolic) = Symbolics.getmetadata(x, VariableShift, 0)
+
+###################
+### Evaluate at ###
+###################
+struct EvalAt <: Symbolics.Operator
+    t::Union{Symbolic, Number}
+end
+
+function (A::EvalAt)(x::Symbolic)
+    if symbolic_type(x) == NotSymbolic() || !iscall(x)
+        if x isa Symbolics.CallWithMetadata
+            return x(A.t)
+        else
+            return x
+        end
+    end
+
+    if iscall(x) && operation(x) == getindex
+        arr = arguments(x)[1]
+        term(getindex, A(arr), arguments(x)[2:end]...)
+    elseif operation(x) isa Differential
+        x = default_toterm(x)
+        A(x)
+    else
+        length(arguments(x)) !== 1 &&
+            error("Variable $x has too many arguments. EvalAt can only be applied to one-argument variables.")
+        (symbolic_type(only(arguments(x))) !== ScalarSymbolic()) && return x
+        return operation(x)(A.t)
+    end
+end
+
+function (A::EvalAt)(x::Union{Num, Symbolics.Arr})
+    wrap(A(unwrap(x)))
+end
+SymbolicUtils.isbinop(::EvalAt) = false
+
+Base.nameof(::EvalAt) = :EvalAt
+Base.show(io::IO, A::EvalAt) = print(io, "EvalAt(", A.t, ")")
+Base.:(==)(A1::EvalAt, A2::EvalAt) = isequal(A1.t, A2.t)
+Base.hash(A::EvalAt, u::UInt) = hash(A.t, u)
diff --git a/test/model_parsing.jl b/test/model_parsing.jl
index e8464707de..fe2bcbfca6 100644
--- a/test/model_parsing.jl
+++ b/test/model_parsing.jl
@@ -1026,3 +1026,35 @@ end
     @named sys = Float2Bool()
     @test typeof(sys) == DiscreteSystem
 end
+
+@testset "Constraints, costs, consolidate" begin
+    @mtkmodel Example begin
+        @variables begin
+            x(t)
+            y(t)
+        end
+        @equations begin
+            x ~ y
+        end
+        @constraints begin
+            EvalAt(0.3)(x) ~ 3
+            y ≲ 4
+        end
+        @costs begin
+            x + y
+            EvalAt(1)(y)^2
+        end
+        @consolidate f(u) = u[1]^2 + log(u[2])
+    end
+
+    @named ex = Example()
+    ex = complete(ex)
+
+    costs = ModelingToolkit.get_costs(ex)
+    constrs = ModelingToolkit.get_constraints(ModelingToolkit.get_constraintsystem(ex))
+    @test isequal(costs[1], ex.x + ex.y)
+    @test isequal(costs[2], EvalAt(1)(ex.y)^2)
+    @test isequal(constrs[1], -3 + EvalAt(0.3)(ex.x) ~ 0)
+    @test isequal(constrs[2], -4 + ex.y ≲ 0)
+    @test ModelingToolkit.get_consolidate(ex)([1, 2]) ≈ 1 + log(2)
+end
diff --git a/test/variable_utils.jl b/test/variable_utils.jl
index 3204d28836..1dc45e11ef 100644
--- a/test/variable_utils.jl
+++ b/test/variable_utils.jl
@@ -158,3 +158,29 @@ end
     @test !isinitial(c)
     @test !isinitial(x)
 end
+
+@testset "At" begin
+    @independent_variables u
+    @variables x(t) v(..) w(t)[1:3]
+    @parameters y z(u, t) r[1:3]
+
+    @test EvalAt(1)(x) isa Num
+    @test isequal(EvalAt(1)(y), y)
+    @test_throws ErrorException EvalAt(1)(z)
+    @test isequal(EvalAt(1)(v), v(1))
+    @test isequal(EvalAt(1)(v(t)), v(1))
+    @test isequal(EvalAt(1)(v(2)), v(2))
+
+    arr = EvalAt(1)(w)
+    var = EvalAt(1)(w[1])
+    @test arr isa Symbolics.Arr
+    @test var isa Num
+
+    @test isequal(EvalAt(1)(r), r)
+    @test isequal(EvalAt(1)(r[2]), r[2])
+
+    _x = ModelingToolkit.unwrap(x)
+    @test EvalAt(1)(_x) isa Symbolics.BasicSymbolic
+    @test only(arguments(EvalAt(1)(_x))) == 1
+    @test EvalAt(1)(D(x)) isa Num
+end