diff --git a/Test/Common.lean b/Test/Common.lean
index 3cad256..5274bad 100644
--- a/Test/Common.lean
+++ b/Test/Common.lean
@@ -48,6 +48,12 @@ namespace Condensed
 deriving instance BEq, Repr for LocalDecl
 deriving instance BEq, Repr for Goal
 
+-- Enable string interpolation
+instance : ToString FVarId where
+  toString id := id.name.toString
+instance : ToString MVarId where
+  toString id := id.name.toString
+
 protected def LocalDecl.devolatilize (decl: LocalDecl): LocalDecl :=
   {
     decl with fvarId := { name := .anonymous }
diff --git a/Test/Integration.lean b/Test/Integration.lean
index dce7e65..7864515 100644
--- a/Test/Integration.lean
+++ b/Test/Integration.lean
@@ -90,27 +90,27 @@ def test_automatic_mode (automatic: Bool): Test :=
     ],
   }
   let goal2l: Protocol.Goal := {
-    name := "_uniq.59",
+    name := "_uniq.61",
     userName? := .some "inl",
     target := { pp? := .some "q ∨ p" },
     vars := varsPQ ++ #[
-      { name := "_uniq.47", userName := "h✝", type? := .some { pp? := .some "p" }, isInaccessible := true}
+      { name := "_uniq.49", userName := "h✝", type? := .some { pp? := .some "p" }, isInaccessible := true}
     ],
   }
   let goal2r: Protocol.Goal := {
-    name := "_uniq.72",
+    name := "_uniq.74",
     userName? := .some "inr",
     target := { pp? := .some "q ∨ p" },
     vars := varsPQ ++ #[
-      { name := "_uniq.60", userName := "h✝", type? := .some { pp? := .some "q" }, isInaccessible := true}
+      { name := "_uniq.62", userName := "h✝", type? := .some { pp? := .some "q" }, isInaccessible := true}
     ],
   }
   let goal3l: Protocol.Goal := {
-    name := "_uniq.78",
+    name := "_uniq.80",
     userName? := .some "inl.h",
     target := { pp? := .some "p" },
     vars := varsPQ ++ #[
-      { name := "_uniq.47", userName := "h✝", type? := .some { pp? := .some "p" }, isInaccessible := true}
+      { name := "_uniq.49", userName := "h✝", type? := .some { pp? := .some "p" }, isInaccessible := true}
     ],
   }
   [
diff --git a/Test/Metavar.lean b/Test/Metavar.lean
index c6fc4f0..276004b 100644
--- a/Test/Metavar.lean
+++ b/Test/Metavar.lean
@@ -239,7 +239,7 @@ def test_partial_continuation: TestM Unit := do
       return ()
     | .ok state => pure state
   addTest $ LSpec.check "(continue)" ((← state1b.serializeGoals (options := ← read)).map (·.target.pp?) =
-    #[.some "2 ≤ ?m.succ", .some "?m.succ ≤ 5", .some "Nat"])
+    #[.some "2 ≤ Nat.succ ?m", .some "Nat.succ ?m ≤ 5", .some "Nat"])
   addTest $ LSpec.test "(2 root)" state1b.rootExpr?.isNone
 
   -- Roundtrip
@@ -253,7 +253,7 @@ def test_partial_continuation: TestM Unit := do
       return ()
     | .ok state => pure state
   addTest $ LSpec.check "(continue)" ((← state1b.serializeGoals (options := ← read)).map (·.target.pp?) =
-    #[.some "2 ≤ ?m.succ", .some "?m.succ ≤ 5", .some "Nat"])
+    #[.some "2 ≤ Nat.succ ?m", .some "Nat.succ ?m ≤ 5", .some "Nat"])
   addTest $ LSpec.test "(2 root)" state1b.rootExpr?.isNone
 
   -- Continuation should fail if the state does not exist:
diff --git a/Test/Proofs.lean b/Test/Proofs.lean
index d7722e2..e13e528 100644
--- a/Test/Proofs.lean
+++ b/Test/Proofs.lean
@@ -241,13 +241,15 @@ def test_or_comm: TestM Unit := do
     | other => do
       addTest $ assertUnreachable $ other.toString
       return ()
-  let fvP := "_uniq.10"
-  let fvQ := "_uniq.13"
-  let fvH := "_uniq.16"
-  let state1g0 := "_uniq.17"
+  let [state1g0] := state1.goals | fail "Should have 1 goal"
+  let (fvP, fvQ, fvH) ← state1.withContext state1g0 do
+    let lctx ← getLCtx
+    let #[fvP, fvQ, fvH] := lctx.getFVarIds.map (toString ·.name) |
+      panic! "Incorrect number of decls"
+    pure (fvP, fvQ, fvH)
   addTest $ LSpec.check tactic ((← state1.serializeGoals (options := ← read)) =
     #[{
-      name := state1g0,
+      name := state1g0.name.toString,
       target := { pp? := .some "q ∨ p" },
       vars := #[
         { name := fvP, userName := "p", type? := .some { pp? := .some "Prop" } },
@@ -269,7 +271,9 @@ def test_or_comm: TestM Unit := do
       return ()
   addTest $ LSpec.check tactic ((← state2.serializeGoals (options := ← read)).map (·.devolatilize) =
     #[branchGoal "inl" "p", branchGoal "inr" "q"])
-  let (caseL, caseR) := ("_uniq.64", "_uniq.77")
+  let [state2g0, state2g1] := state2.goals |
+    fail s!"Should have 2 goals, but it has {state2.goals.length}"
+  let (caseL, caseR) := (state2g0.name.toString, state2g1.name.toString)
   addTest $ LSpec.check tactic ((← state2.serializeGoals (options := ← read)).map (·.name) =
     #[caseL, caseR])
   addTest $ LSpec.check "(2 parent exists)" state2.parentExpr?.isSome
@@ -293,7 +297,8 @@ def test_or_comm: TestM Unit := do
       return ()
   let state3_1parent ← state3_1.withParentContext do
     serializeExpressionSexp (← instantiateAll state3_1.parentExpr?.get!)
-  addTest $ LSpec.test "(3_1 parent)" (state3_1parent == s!"((:c Or.inr) (:fv {fvQ}) (:fv {fvP}) (:mv _uniq.91))")
+  let [state3_1goal0] := state3_1.goals | fail "Should have 1 goal"
+  addTest $ LSpec.test "(3_1 parent)" (state3_1parent == s!"((:c Or.inr) (:fv {fvQ}) (:fv {fvP}) (:mv {state3_1goal0}))")
   addTest $ LSpec.check "· apply Or.inr" (state3_1.goals.length = 1)
   let state4_1 ← match ← state3_1.tacticOn (goalId := 0) (tactic := "assumption") with
     | .success state => pure state
@@ -559,12 +564,15 @@ def test_nat_zero_add: TestM Unit := do
     | other => do
       addTest $ assertUnreachable $ other.toString
       return ()
+  let [mvarMotive, mvarMajor, mvarInduct, mvarConduit] := state2.goals |
+      fail "Incorrect number of goals"
+  let .num _ major := mvarMajor.name | fail "Incorrect form of mvar id"
   addTest $ LSpec.check s!"mapply {recursor}" ((← state2.serializeGoals (options := ← read)).map (·.devolatilizeVars) =
     #[
-      buildNamedGoal "_uniq.71" [("n", "Nat")] "Nat → Prop" (.some "motive"),
-      buildNamedGoal "_uniq.72" [("n", "Nat")] "Nat",
-      buildNamedGoal "_uniq.73" [("n", "Nat")] "∀ (t : Nat), Nat.below t → ?motive t",
-      buildNamedGoal "_uniq.74" [("n", "Nat")] "?motive ?m.72 = (n + 0 = n)" (.some "conduit")
+      buildNamedGoal mvarMotive.name.toString  [("n", "Nat")] "Nat → Prop" (.some "motive"),
+      buildNamedGoal mvarMajor.name.toString   [("n", "Nat")] "Nat",
+      buildNamedGoal mvarInduct.name.toString  [("n", "Nat")] "∀ (t : Nat), Nat.below t → ?motive t",
+      buildNamedGoal mvarConduit.name.toString [("n", "Nat")] s!"?motive ?m.{major} = (n + 0 = n)" (.some "conduit")
     ])
 
   let tactic := "exact n"
@@ -647,13 +655,15 @@ def test_nat_zero_add_alt: TestM Unit := do
     | other => do
       addTest $ assertUnreachable $ other.toString
       return ()
-  let major := "_uniq.72"
+  let [mvarMotive, mvarMajor, mvarInduct, mvarConduit] := state2.goals |
+      fail "Incorrect number of goals"
+  let .num _ major := mvarMajor.name | fail "Incorrect form of mvar id"
   addTest $ LSpec.check s!"mapply {recursor}" ((← state2.serializeGoals (options := ← read)).map (·.devolatilizeVars) =
     #[
-      buildNamedGoal "_uniq.71" [("n", "Nat")] "Nat → Prop" (.some "motive"),
-      buildNamedGoal major [("n", "Nat")] "Nat",
-      buildNamedGoal "_uniq.73" [("n", "Nat")] "∀ (t : Nat), Nat.below t → ?motive t",
-      buildNamedGoal "_uniq.74" [("n", "Nat")] "?motive ?m.72 = (n + 0 = n)" (.some "conduit")
+      buildNamedGoal mvarMotive.name.toString [("n", "Nat")] "Nat → Prop" (.some "motive"),
+      buildNamedGoal mvarMajor.name.toString [("n", "Nat")] "Nat",
+      buildNamedGoal mvarInduct.name.toString [("n", "Nat")] "∀ (t : Nat), Nat.below t → ?motive t",
+      buildNamedGoal mvarConduit.name.toString [("n", "Nat")] s!"?motive ?m.{major} = (n + 0 = n)" (.some "conduit")
     ])
 
   let tactic := "intro x"
@@ -670,8 +680,7 @@ def test_nat_zero_add_alt: TestM Unit := do
     | other => do
       addTest $ assertUnreachable $ other.toString
       return ()
-  let (eqL, eqR, eqT) := ("_uniq.92", "_uniq.93", "_uniq.91")
-  addTest $ LSpec.check tactic $ state3m2.goals.map (·.name.toString) = [eqL, eqR, eqT]
+  let [eqL, eqR, eqT] := state3m2.goals | fail "Incorrect number of goals"
   let [_motive, _major, _step, conduit] := state2.goals | panic! "Goals conflict"
   let state2b ← match state3m2.resume [conduit] with
     | .ok state => pure state
@@ -681,20 +690,26 @@ def test_nat_zero_add_alt: TestM Unit := do
 
   let cNatAdd := "(:c HAdd.hAdd) (:c Nat) (:c Nat) (:c Nat) ((:c instHAdd) (:c Nat) (:c instAddNat))"
   let cNat0 := "((:c OfNat.ofNat) (:c Nat) (:lit 0) ((:c instOfNatNat) (:lit 0)))"
-  let fvN := "_uniq.67"
+  let fvN ← state2b.withContext conduit do
+    let lctx ← getLCtx
+    pure $ lctx.getFVarIds.get! 0 |>.name
   let conduitRight := s!"((:c Eq) (:c Nat) ({cNatAdd} (:fv {fvN}) {cNat0}) (:fv {fvN}))"
-  let substOf (mv: String) := s!"(:subst (:mv {mv}) (:fv {fvN}) (:mv {major}))"
+  let substOf (mvarId: MVarId) := s!"(:subst (:mv {mvarId.name}) (:fv {fvN}) (:mv {mvarMajor}))"
+  let .num _ nL := eqL.name | fail "Incorrect form of mvar id"
+  let .num _ nR := eqR.name | fail "Incorrect form of mvar id"
+  let nL' := nL + 4
+  let nR' := nR + 5
   addTest $ LSpec.check "resume" ((← state2b.serializeGoals (options := { ← read with printExprAST := true })) =
     #[
       {
-        name := "_uniq.74",
+        name := mvarConduit.name.toString,
         userName? := .some "conduit",
         target := {
-          pp? := .some "(?m.96 ?m.72 = ?m.98 ?m.72) = (n + 0 = n)",
+          pp? := .some s!"(?m.{nL'} ?m.{major} = ?m.{nR'} ?m.{major}) = (n + 0 = n)",
           sexp? := .some s!"((:c Eq) (:sort 0) ((:c Eq) {substOf eqT} {substOf eqL} {substOf eqR}) {conduitRight})",
         },
         vars := #[{
-          name := fvN,
+          name := fvN.toString,
           userName := "n",
           type? := .some { pp? := .some "Nat", sexp? := .some "(:c Nat)" },
         }],
diff --git a/Test/Tactic/Congruence.lean b/Test/Tactic/Congruence.lean
index 180c2f4..e861b2f 100644
--- a/Test/Tactic/Congruence.lean
+++ b/Test/Tactic/Congruence.lean
@@ -28,7 +28,7 @@ def test_congr_arg_list : TestT Elab.TermElabM Unit := do
     let results ← Meta.withAssignableSyntheticOpaque do f.apply (← parseSentence "List.reverse")
     addTest $ LSpec.check "apply" (results.length = 0)
     addTest $ LSpec.check "h" ((← exprToStr $ ← h.getType) = "?a₁ = ?a₂")
-    addTest $ LSpec.check "conduit" ((← exprToStr $ ← c.getType) = "(?a₁.reverse = ?a₂.reverse) = (l1.reverse = l2.reverse)")
+    addTest $ LSpec.check "conduit" ((← exprToStr $ ← c.getType) = "(List.reverse ?a₁ = List.reverse ?a₂) = (l1.reverse = l2.reverse)")
 def test_congr_arg : TestT Elab.TermElabM Unit := do
   let expr := "λ (n m: Nat) (h: n = m) => n * n = m * m"
   let expr ← parseSentence expr
@@ -37,7 +37,7 @@ def test_congr_arg : TestT Elab.TermElabM Unit := do
     let newGoals ← runTacticOnMVar Tactic.evalCongruenceArg target.mvarId!
     addTest $  LSpec.check "goals" ((← newGoals.mapM (λ x => mvarUserNameAndType x)) =
       [
-        (`α, "Sort ?u.70"),
+        (`α, "Sort ?u.73"),
         (`a₁, "?α"),
         (`a₂, "?α"),
         (`f, "?α → Nat"),
@@ -52,7 +52,7 @@ def test_congr_fun : TestT Elab.TermElabM Unit := do
     let newGoals ← runTacticOnMVar Tactic.evalCongruenceFun target.mvarId!
     addTest $ LSpec.check "goals" ((← newGoals.mapM (λ x => mvarUserNameAndType x)) =
       [
-        (`α, "Sort ?u.159"),
+        (`α, "Sort ?u.165"),
         (`f₁, "?α → Nat"),
         (`f₂, "?α → Nat"),
         (`h, "?f₁ = ?f₂"),
diff --git a/Test/Tactic/MotivatedApply.lean b/Test/Tactic/MotivatedApply.lean
index 66bb336..2da643e 100644
--- a/Test/Tactic/MotivatedApply.lean
+++ b/Test/Tactic/MotivatedApply.lean
@@ -40,7 +40,7 @@ def test_nat_brec_on : TestT Elab.TermElabM Unit := do
         "Nat → Prop",
         "Nat",
         "∀ (t : Nat), Nat.below t → ?motive t",
-        "?motive ?m.71 = (n + 0 = n)",
+        "?motive ?m.74 = (n + 0 = n)",
       ])
     addTest test
 
@@ -83,7 +83,7 @@ def test_partial_motive_instantiation : TestT Elab.TermElabM Unit := do
     let target ← Meta.mkFreshExprSyntheticOpaqueMVar body
     let tactic := Tactic.evalMotivatedApply recursor
     let newGoals ← runTacticOnMVar tactic target.mvarId!
-    let majorId := 71
+    let majorId := 74
     addTest $ (LSpec.check "goals" ((← newGoals.mapM (λ g => do exprToStr (← g.getType))) =
       [
         "Nat → Prop",
@@ -100,7 +100,7 @@ def test_partial_motive_instantiation : TestT Elab.TermElabM Unit := do
 
     addTest $ ← conduit.withContext do
       let t := toString (← Meta.ppExpr $ ← conduit.getType)
-      return LSpec.check "conduit" (t = s!"(?m.{majorId}.add + 0 = ?m.146 ?m.{majorId}) = (n + 0 = n)")
+      return LSpec.check "conduit" (t = s!"(Nat.add ?m.{majorId} + 0 = ?m.149 ?m.{majorId}) = (n + 0 = n)")
 
 def suite (env: Environment): List (String × IO LSpec.TestSeq) :=
   [