diff --git a/spacy/syntax/arc_eager.pyx b/spacy/syntax/arc_eager.pyx
index afa05bd9a..f1dbcf426 100644
--- a/spacy/syntax/arc_eager.pyx
+++ b/spacy/syntax/arc_eager.pyx
@@ -1,6 +1,9 @@
 # cython: profile=True
 from __future__ import unicode_literals
 
+import ctypes
+import os
+
 from ._state cimport State
 from ._state cimport has_head, get_idx, get_s0, get_n0, get_left, get_right
 from ._state cimport is_final, at_eol, pop_stack, push_stack, add_dep
@@ -15,6 +18,12 @@ from .transition_system cimport move_cost_func_t, label_cost_func_t
 from ..gold cimport GoldParse
 from ..gold cimport GoldParseC
 
+from libc.stdint cimport uint32_t
+from libc.string cimport memcpy
+
+from cymem.cymem cimport Pool
+from ..stateclass cimport StateClass
+
 
 DEF NON_MONOTONIC = True
 DEF USE_BREAK = True
@@ -78,7 +87,6 @@ cdef int arc_cost(const State* st, const GoldParseC* gold, int head, int child)
         return 0
 
 
-
 cdef bint arc_is_gold(const GoldParseC* gold, int head, int child) except -1:
     if gold.labels[child] == -1:
         return True
@@ -110,6 +118,11 @@ cdef class Shift:
     cdef bint is_valid(const State* s, int label) except -1:
         return not at_eol(s)
 
+    @staticmethod
+    cdef bint _new_is_valid(StateClass st, int label) except -1:
+        return not st.eol()
+
+
     @staticmethod
     cdef int transition(State* state, int label) except -1:
         # Set the dep label, in case we need it after we reduce
@@ -133,6 +146,13 @@ cdef class Shift:
 
 
 cdef class Reduce:
+    @staticmethod
+    cdef bint _new_is_valid(StateClass st, int label) except -1:
+        if NON_MONOTONIC:
+            return st.stack_depth() >= 2 #and not missing_brackets(s)
+        else:
+            return st.stack_depth() >= 2 and st.has_head(st.S(0))
+
     @staticmethod
     cdef bint is_valid(const State* s, int label) except -1:
         if NON_MONOTONIC:
@@ -165,6 +185,13 @@ cdef class Reduce:
 
 
 cdef class LeftArc:
+    @staticmethod
+    cdef bint _new_is_valid(StateClass st, int label) except -1:
+        if NON_MONOTONIC:
+            return st.stack_depth() >= 1 #and not missing_brackets(s)
+        else:
+            return st.stack_depth() >= 1 and not st.has_head(st.S(0))
+
     @staticmethod
     cdef bint is_valid(const State* s, int label) except -1:
         if NON_MONOTONIC:
@@ -206,6 +233,10 @@ cdef class RightArc:
     cdef bint is_valid(const State* s, int label) except -1:
         return s.stack_len >= 1 and not at_eol(s)
 
+    @staticmethod
+    cdef bint _new_is_valid(StateClass st, int label) except -1:
+        return st.stack_depth() >= 1 and not st.eol()
+
     @staticmethod
     cdef int transition(State* state, int label) except -1:
         add_dep(state, state.stack[0], state.i, label)
@@ -230,6 +261,32 @@ cdef class RightArc:
 
 
 cdef class Break:
+    @staticmethod
+    cdef bint _new_is_valid(StateClass st, int label) except -1:
+        cdef int i
+        if not USE_BREAK:
+            return False
+        elif st.eol():
+            return False
+        elif st.stack_depth() < 1:
+            return False
+        elif NON_MONOTONIC:
+            return True
+        else:
+            # In the Break transition paper, they have this constraint that prevents
+            # Break if stack is disconnected. But, if we're doing non-monotonic parsing,
+            # we prefer to relax this constraint. This is helpful in parsing whole
+            # documents, because then we don't get stuck with words on the stack.
+            seen_headless = False
+            for i in range(st.stack_depth()):
+                if not st.has_head(st.S(i)):
+                    if seen_headless:
+                        return False
+                    else:
+                        seen_headless = True
+            # TODO: Constituency constraints
+            return True
+
     @staticmethod
     cdef bint is_valid(const State* s, int label) except -1:
         cdef int i
@@ -584,14 +641,17 @@ cdef class ArcEager(TransitionSystem):
             output[i] = move_costs[move] + label_cost_funcs[move](s, &gold.c, label)
 
     cdef Transition best_valid(self, const weight_t* scores, const State* s) except *:
+        cdef Pool mem = Pool()
+        cdef StateClass stcls = StateClass.from_struct(mem, s)
         cdef bint[N_MOVES] is_valid
-        is_valid[SHIFT] = Shift.is_valid(s, -1)
-        is_valid[REDUCE] = Reduce.is_valid(s, -1)
-        is_valid[LEFT] = LeftArc.is_valid(s, -1)
-        is_valid[RIGHT] = RightArc.is_valid(s, -1)
-        is_valid[BREAK] = Break.is_valid(s, -1)
-        is_valid[CONSTITUENT] = Constituent.is_valid(s, -1)
-        is_valid[ADJUST] = Adjust.is_valid(s, -1)
+        #is_valid[SHIFT] = Shift.is_valid(s, -1)
+        is_valid[SHIFT] = Shift._new_is_valid(stcls, -1)
+        is_valid[REDUCE] = Reduce._new_is_valid(stcls, -1)
+        is_valid[LEFT] = LeftArc._new_is_valid(stcls, -1)
+        is_valid[RIGHT] = RightArc._new_is_valid(stcls, -1)
+        is_valid[BREAK] = Break._new_is_valid(stcls, -1)
+        is_valid[CONSTITUENT] = False # Constituent._new_is_valid(s, -1)
+        is_valid[ADJUST] = False # Adjust._new_is_valid(s, -1)
         cdef Transition best
         cdef weight_t score = MIN_SCORE
         cdef int i