diff --git a/toolchain/check/eval.cpp b/toolchain/check/eval.cpp
index 3dec0d4fceed..06a133fc071d 100644
--- a/toolchain/check/eval.cpp
+++ b/toolchain/check/eval.cpp
@@ -1893,16 +1893,16 @@ auto TryEvalBlockForSpecific(Context& context, SemIRLoc loc,
   Diagnostics::AnnotationScope annotate_diagnostics(
       &context.emitter(), [&](auto& builder) {
         CARBON_DIAGNOSTIC(ResolvingSpecificHere, Note, "in {0} used here",
-                          InstIdAsType);
-        builder.Note(loc, ResolvingSpecificHere,
-                     GetInstForSpecific(context, specific_id));
+                          SemIR::SpecificId);
+        builder.Note(loc, ResolvingSpecificHere, specific_id);
       });
 
   for (auto [i, inst_id] : llvm::enumerate(eval_block)) {
     auto const_id = TryEvalInstInContext(eval_context, inst_id,
                                          context.insts().Get(inst_id));
     result[i] = context.constant_values().GetInstId(const_id);
-    CARBON_CHECK(result[i].has_value());
+    CARBON_CHECK(result[i].has_value(), "Failed to evaluate {0} in eval block",
+                 context.insts().Get(inst_id));
   }
 
   return context.inst_blocks().Add(result);
diff --git a/toolchain/check/generic.cpp b/toolchain/check/generic.cpp
index 43ff2e366895..0da9d57b4436 100644
--- a/toolchain/check/generic.cpp
+++ b/toolchain/check/generic.cpp
@@ -608,40 +608,6 @@ auto ResolveSpecificDefinition(Context& context, SemIRLoc loc,
   return true;
 }
 
-auto GetInstForSpecific(Context& context, SemIR::SpecificId specific_id)
-    -> SemIR::InstId {
-  CARBON_CHECK(specific_id.has_value());
-  const auto& specific = context.specifics().Get(specific_id);
-  const auto& generic = context.generics().Get(specific.generic_id);
-  auto decl = context.insts().Get(generic.decl_id);
-  CARBON_KIND_SWITCH(decl) {
-    case CARBON_KIND(SemIR::ClassDecl class_decl): {
-      return context.types().GetInstId(
-          GetClassType(context, class_decl.class_id, specific_id));
-    }
-    case CARBON_KIND(SemIR::InterfaceDecl interface_decl): {
-      return context.types().GetInstId(
-          GetInterfaceType(context, interface_decl.interface_id, specific_id));
-    }
-    case SemIR::FunctionDecl::Kind: {
-      return context.constant_values().GetInstId(TryEvalInst(
-          context, SemIR::InstId::None,
-          SemIR::SpecificFunction{
-              .type_id = GetSingletonType(
-                  context, SemIR::SpecificFunctionType::SingletonInstId),
-              .callee_id = generic.decl_id,
-              .specific_id = specific_id}));
-    }
-    case SemIR::AssociatedConstantDecl::Kind: {
-      // TODO: We don't have a good instruction to use here.
-      return generic.decl_id;
-    }
-    default: {
-      CARBON_FATAL("Unknown kind for generic declaration {0}", decl);
-    }
-  }
-}
-
 auto DiagnoseIfGenericMissingExplicitParameters(
     Context& context, SemIR::EntityWithParamsBase& entity_base) -> void {
   if (!entity_base.implicit_param_patterns_id.has_value() ||
diff --git a/toolchain/check/generic.h b/toolchain/check/generic.h
index 22f2884236ae..9abfcb511a4d 100644
--- a/toolchain/check/generic.h
+++ b/toolchain/check/generic.h
@@ -82,11 +82,6 @@ auto ResolveSpecificDeclaration(Context& context, SemIRLoc loc,
 auto ResolveSpecificDefinition(Context& context, SemIRLoc loc,
                                SemIR::SpecificId specific_id) -> bool;
 
-// Returns an instruction describing the entity named by the given specific.
-// This is used to name the entity in diagnostics.
-auto GetInstForSpecific(Context& context, SemIR::SpecificId specific_id)
-    -> SemIR::InstId;
-
 // Diagnoses if an entity has implicit parameters, indicating it's generic, but
 // is missing explicit parameters.
 auto DiagnoseIfGenericMissingExplicitParameters(
diff --git a/toolchain/check/name_lookup.cpp b/toolchain/check/name_lookup.cpp
index c3f057a6d038..edeb8bd5720d 100644
--- a/toolchain/check/name_lookup.cpp
+++ b/toolchain/check/name_lookup.cpp
@@ -349,17 +349,23 @@ static auto DiagnoseMemberNameNotFound(
     llvm::ArrayRef<LookupScope> lookup_scopes) -> void {
   if (lookup_scopes.size() == 1 &&
       lookup_scopes.front().name_scope_id.has_value()) {
-    auto specific_id = lookup_scopes.front().specific_id;
-    auto scope_inst_id = specific_id.has_value()
-                             ? GetInstForSpecific(context, specific_id)
-                             : context.name_scopes()
-                                   .Get(lookup_scopes.front().name_scope_id)
-                                   .inst_id();
-    CARBON_DIAGNOSTIC(MemberNameNotFoundInScope, Error,
-                      "member name `{0}` not found in {1}", SemIR::NameId,
-                      InstIdAsType);
-    context.emitter().Emit(loc, MemberNameNotFoundInScope, name_id,
-                           scope_inst_id);
+    if (auto specific_id = lookup_scopes.front().specific_id;
+        specific_id.has_value()) {
+      CARBON_DIAGNOSTIC(MemberNameNotFoundInSpecificScope, Error,
+                        "member name `{0}` not found in {1}", SemIR::NameId,
+                        SemIR::SpecificId);
+      context.emitter().Emit(loc, MemberNameNotFoundInSpecificScope, name_id,
+                             specific_id);
+    } else {
+      auto scope_inst_id = context.name_scopes()
+                               .Get(lookup_scopes.front().name_scope_id)
+                               .inst_id();
+      CARBON_DIAGNOSTIC(MemberNameNotFoundInInstScope, Error,
+                        "member name `{0}` not found in {1}", SemIR::NameId,
+                        InstIdAsType);
+      context.emitter().Emit(loc, MemberNameNotFoundInInstScope, name_id,
+                             scope_inst_id);
+    }
     return;
   }
 
diff --git a/toolchain/check/sem_ir_loc_diagnostic_emitter.cpp b/toolchain/check/sem_ir_loc_diagnostic_emitter.cpp
index d0c7b05f38a0..b4bdf525ffec 100644
--- a/toolchain/check/sem_ir_loc_diagnostic_emitter.cpp
+++ b/toolchain/check/sem_ir_loc_diagnostic_emitter.cpp
@@ -114,6 +114,9 @@ auto SemIRLocDiagnosticEmitter::ConvertArg(llvm::Any arg) const -> llvm::Any {
            StringifyTypeExpr(*sem_ir_, sem_ir_->types().GetInstId(*type_id)) +
            "`";
   }
+  if (auto* specific_id = llvm::any_cast<SemIR::SpecificId>(&arg)) {
+    return "`" + StringifySpecific(*sem_ir_, *specific_id) + "`";
+  }
   if (auto* typed_int = llvm::any_cast<TypedInt>(&arg)) {
     return llvm::APSInt(typed_int->value,
                         !sem_ir_->types().IsSignedInt(typed_int->type));
diff --git a/toolchain/check/testdata/alias/no_prelude/fail_local_in_namespace.carbon b/toolchain/check/testdata/alias/no_prelude/fail_local_in_namespace.carbon
index 286e74b5884e..3cb22cdb38f9 100644
--- a/toolchain/check/testdata/alias/no_prelude/fail_local_in_namespace.carbon
+++ b/toolchain/check/testdata/alias/no_prelude/fail_local_in_namespace.carbon
@@ -20,7 +20,7 @@ fn F() -> {} {
   // CHECK:STDERR:                ^~
   // CHECK:STDERR:
   alias NS.a = {};
-  // CHECK:STDERR: fail_local_in_namespace.carbon:[[@LINE+4]]:10: error: member name `a` not found in `NS` [MemberNameNotFoundInScope]
+  // CHECK:STDERR: fail_local_in_namespace.carbon:[[@LINE+4]]:10: error: member name `a` not found in `NS` [MemberNameNotFoundInInstScope]
   // CHECK:STDERR:   return NS.a;
   // CHECK:STDERR:          ^~~~
   // CHECK:STDERR:
diff --git a/toolchain/check/testdata/alias/no_prelude/import_access.carbon b/toolchain/check/testdata/alias/no_prelude/import_access.carbon
index f4ae95d08465..31e91b4b9767 100644
--- a/toolchain/check/testdata/alias/no_prelude/import_access.carbon
+++ b/toolchain/check/testdata/alias/no_prelude/import_access.carbon
@@ -47,7 +47,7 @@ package Other library "[[@TEST_NAME]]";
 
 import Test library "def";
 
-// CHECK:STDERR: fail_other_def.carbon:[[@LINE+4]]:11: error: member name `A` not found in `Test` [MemberNameNotFoundInScope]
+// CHECK:STDERR: fail_other_def.carbon:[[@LINE+4]]:11: error: member name `A` not found in `Test` [MemberNameNotFoundInInstScope]
 // CHECK:STDERR: var inst: Test.A = {};
 // CHECK:STDERR:           ^~~~~~
 // CHECK:STDERR:
diff --git a/toolchain/check/testdata/class/adapter/adapt.carbon b/toolchain/check/testdata/class/adapter/adapt.carbon
index 03bf06080e61..b765050ab8fa 100644
--- a/toolchain/check/testdata/class/adapter/adapt.carbon
+++ b/toolchain/check/testdata/class/adapter/adapt.carbon
@@ -39,7 +39,7 @@ class AdaptNotExtend {
 
 fn F(a: AdaptNotExtend) {
   // `Adapted` is not extended, so lookup for `F` finds nothing.
-  // CHECK:STDERR: fail_not_extend.carbon:[[@LINE+4]]:3: error: member name `F` not found in `AdaptNotExtend` [MemberNameNotFoundInScope]
+  // CHECK:STDERR: fail_not_extend.carbon:[[@LINE+4]]:3: error: member name `F` not found in `AdaptNotExtend` [MemberNameNotFoundInInstScope]
   // CHECK:STDERR:   a.F();
   // CHECK:STDERR:   ^~~
   // CHECK:STDERR:
diff --git a/toolchain/check/testdata/class/adapter/extend_adapt.carbon b/toolchain/check/testdata/class/adapter/extend_adapt.carbon
index d38b792a58fc..46e705dc7b4a 100644
--- a/toolchain/check/testdata/class/adapter/extend_adapt.carbon
+++ b/toolchain/check/testdata/class/adapter/extend_adapt.carbon
@@ -95,7 +95,7 @@ class StructAdapter {
 
 fn F(a: StructAdapter) -> i32 {
   // TODO: This should be allowed.
-  // CHECK:STDERR: fail_todo_adapt_struct.carbon:[[@LINE+4]]:10: error: member name `b` not found in `StructAdapter` [MemberNameNotFoundInScope]
+  // CHECK:STDERR: fail_todo_adapt_struct.carbon:[[@LINE+4]]:10: error: member name `b` not found in `StructAdapter` [MemberNameNotFoundInInstScope]
   // CHECK:STDERR:   return a.b;
   // CHECK:STDERR:          ^~~
   // CHECK:STDERR:
@@ -131,7 +131,7 @@ class IntAdapter {
 
 fn F(a: IntAdapter) -> i32 {
   // Builtin types have no member names.
-  // CHECK:STDERR: fail_adapt_builtin.carbon:[[@LINE+4]]:10: error: member name `foo` not found in `IntAdapter` [MemberNameNotFoundInScope]
+  // CHECK:STDERR: fail_adapt_builtin.carbon:[[@LINE+4]]:10: error: member name `foo` not found in `IntAdapter` [MemberNameNotFoundInInstScope]
   // CHECK:STDERR:   return a.foo;
   // CHECK:STDERR:          ^~~~~
   // CHECK:STDERR:
diff --git a/toolchain/check/testdata/class/adapter/fail_adapt_bad_decl.carbon b/toolchain/check/testdata/class/adapter/fail_adapt_bad_decl.carbon
index a2662ce85b69..dd23a0b871ca 100644
--- a/toolchain/check/testdata/class/adapter/fail_adapt_bad_decl.carbon
+++ b/toolchain/check/testdata/class/adapter/fail_adapt_bad_decl.carbon
@@ -23,7 +23,7 @@ class Bad {
   adapt 100;
 }
 
-// CHECK:STDERR: fail_not_type.carbon:[[@LINE+4]]:18: error: member name `F` not found in `Bad` [MemberNameNotFoundInScope]
+// CHECK:STDERR: fail_not_type.carbon:[[@LINE+4]]:18: error: member name `F` not found in `Bad` [MemberNameNotFoundInInstScope]
 // CHECK:STDERR: fn Use(b: Bad) { b.F(); }
 // CHECK:STDERR:                  ^~~
 // CHECK:STDERR:
diff --git a/toolchain/check/testdata/class/fail_base_bad_type.carbon b/toolchain/check/testdata/class/fail_base_bad_type.carbon
index 9d6de7768456..662aff4d8372 100644
--- a/toolchain/check/testdata/class/fail_base_bad_type.carbon
+++ b/toolchain/check/testdata/class/fail_base_bad_type.carbon
@@ -56,7 +56,7 @@ class DeriveFromi32 {
 // but it shouldn't crash.
 fn ConvertToBadBasei32(p: DeriveFromi32*) -> i32* { return p; }
 
-// CHECK:STDERR: fail_derive_from_i32.carbon:[[@LINE+4]]:70: error: member name `n` not found in `DeriveFromi32` [MemberNameNotFoundInScope]
+// CHECK:STDERR: fail_derive_from_i32.carbon:[[@LINE+4]]:70: error: member name `n` not found in `DeriveFromi32` [MemberNameNotFoundInInstScope]
 // CHECK:STDERR: fn AccessMemberWithInvalidBasei32(p: DeriveFromi32*) -> i32 { return (*p).n; }
 // CHECK:STDERR:                                                                      ^~~~~~
 // CHECK:STDERR:
@@ -171,7 +171,7 @@ fn AccessMemberWithInvalidBaseFinal_WithMember(p: DeriveFromFinal*) -> i32 {
 }
 
 fn AccessMemberWithInvalidBaseFinal_NoMember(p: DeriveFromFinal*) -> i32 {
-  // CHECK:STDERR: fail_derive_from_final.carbon:[[@LINE+4]]:10: error: member name `b` not found in `DeriveFromFinal` [MemberNameNotFoundInScope]
+  // CHECK:STDERR: fail_derive_from_final.carbon:[[@LINE+4]]:10: error: member name `b` not found in `DeriveFromFinal` [MemberNameNotFoundInInstScope]
   // CHECK:STDERR:   return (*p).b;
   // CHECK:STDERR:          ^~~~~~
   // CHECK:STDERR:
diff --git a/toolchain/check/testdata/class/fail_unknown_member.carbon b/toolchain/check/testdata/class/fail_unknown_member.carbon
index 35dfded8abb5..236794e00ed3 100644
--- a/toolchain/check/testdata/class/fail_unknown_member.carbon
+++ b/toolchain/check/testdata/class/fail_unknown_member.carbon
@@ -14,7 +14,7 @@ class Class {
 
 fn G(c: Class) -> i32 {
   // TODO: Mention the scope in which we looked for the name.
-  // CHECK:STDERR: fail_unknown_member.carbon:[[@LINE+4]]:10: error: member name `something` not found in `Class` [MemberNameNotFoundInScope]
+  // CHECK:STDERR: fail_unknown_member.carbon:[[@LINE+4]]:10: error: member name `something` not found in `Class` [MemberNameNotFoundInInstScope]
   // CHECK:STDERR:   return c.something;
   // CHECK:STDERR:          ^~~~~~~~~~~
   // CHECK:STDERR:
diff --git a/toolchain/check/testdata/class/generic/member_lookup.carbon b/toolchain/check/testdata/class/generic/member_lookup.carbon
index e4d88724ce3c..dbdd40c6b664 100644
--- a/toolchain/check/testdata/class/generic/member_lookup.carbon
+++ b/toolchain/check/testdata/class/generic/member_lookup.carbon
@@ -47,7 +47,7 @@ class Derived(T:! type) {
 }
 
 fn AccessMissingBase[T:! type](x: Base(T)) -> T {
-  // CHECK:STDERR: fail_no_member.carbon:[[@LINE+4]]:10: error: member name `nonesuch` not found in `Base(T)` [MemberNameNotFoundInScope]
+  // CHECK:STDERR: fail_no_member.carbon:[[@LINE+4]]:10: error: member name `nonesuch` not found in `Base(T)` [MemberNameNotFoundInSpecificScope]
   // CHECK:STDERR:   return x.nonesuch;
   // CHECK:STDERR:          ^~~~~~~~~~
   // CHECK:STDERR:
@@ -55,7 +55,7 @@ fn AccessMissingBase[T:! type](x: Base(T)) -> T {
 }
 
 fn AccessMissingDerived[T:! type](x: Derived(T)) -> T {
-  // CHECK:STDERR: fail_no_member.carbon:[[@LINE+4]]:10: error: member name `nonesuch` not found in `Derived(T)` [MemberNameNotFoundInScope]
+  // CHECK:STDERR: fail_no_member.carbon:[[@LINE+4]]:10: error: member name `nonesuch` not found in `Derived(T)` [MemberNameNotFoundInSpecificScope]
   // CHECK:STDERR:   return x.nonesuch;
   // CHECK:STDERR:          ^~~~~~~~~~
   // CHECK:STDERR:
@@ -63,7 +63,7 @@ fn AccessMissingDerived[T:! type](x: Derived(T)) -> T {
 }
 
 fn AccessMissingConcrete(x: Derived(i32)) -> i32 {
-  // CHECK:STDERR: fail_no_member.carbon:[[@LINE+4]]:10: error: member name `nonesuch` not found in `Derived(i32)` [MemberNameNotFoundInScope]
+  // CHECK:STDERR: fail_no_member.carbon:[[@LINE+4]]:10: error: member name `nonesuch` not found in `Derived(i32)` [MemberNameNotFoundInSpecificScope]
   // CHECK:STDERR:   return x.nonesuch;
   // CHECK:STDERR:          ^~~~~~~~~~
   // CHECK:STDERR:
diff --git a/toolchain/check/testdata/class/no_prelude/import_access.carbon b/toolchain/check/testdata/class/no_prelude/import_access.carbon
index 9cd92aff6837..52ea8bbb6aed 100644
--- a/toolchain/check/testdata/class/no_prelude/import_access.carbon
+++ b/toolchain/check/testdata/class/no_prelude/import_access.carbon
@@ -60,7 +60,7 @@ package Other library "[[@TEST_NAME]]";
 
 import Test library "def";
 
-// CHECK:STDERR: fail_other_def.carbon:[[@LINE+4]]:8: error: member name `Def` not found in `Test` [MemberNameNotFoundInScope]
+// CHECK:STDERR: fail_other_def.carbon:[[@LINE+4]]:8: error: member name `Def` not found in `Test` [MemberNameNotFoundInInstScope]
 // CHECK:STDERR: var c: Test.Def = {};
 // CHECK:STDERR:        ^~~~~~~~
 // CHECK:STDERR:
@@ -90,7 +90,7 @@ package Other library "[[@TEST_NAME]]";
 
 import Test library "forward_with_def";
 
-// CHECK:STDERR: fail_other_forward_with_def.carbon:[[@LINE+4]]:8: error: member name `ForwardWithDef` not found in `Test` [MemberNameNotFoundInScope]
+// CHECK:STDERR: fail_other_forward_with_def.carbon:[[@LINE+4]]:8: error: member name `ForwardWithDef` not found in `Test` [MemberNameNotFoundInInstScope]
 // CHECK:STDERR: var c: Test.ForwardWithDef = {};
 // CHECK:STDERR:        ^~~~~~~~~~~~~~~~~~~
 // CHECK:STDERR:
@@ -122,7 +122,7 @@ package Other library "[[@TEST_NAME]]";
 
 import Test library "forward";
 
-// CHECK:STDERR: fail_other_forward.carbon:[[@LINE+4]]:9: error: member name `Forward` not found in `Test` [MemberNameNotFoundInScope]
+// CHECK:STDERR: fail_other_forward.carbon:[[@LINE+4]]:9: error: member name `Forward` not found in `Test` [MemberNameNotFoundInInstScope]
 // CHECK:STDERR: fn F(c: Test.Forward*) {}
 // CHECK:STDERR:         ^~~~~~~~~~~~
 // CHECK:STDERR:
diff --git a/toolchain/check/testdata/class/no_prelude/name_poisoning.carbon b/toolchain/check/testdata/class/no_prelude/name_poisoning.carbon
index 7a022343becc..56a585cef001 100644
--- a/toolchain/check/testdata/class/no_prelude/name_poisoning.carbon
+++ b/toolchain/check/testdata/class/no_prelude/name_poisoning.carbon
@@ -67,7 +67,7 @@ namespace N;
 fn N.F1() -> C;
 
 // Use `N.C` which was poisoned and not declared.
-// CHECK:STDERR: fail_use_poison.carbon:[[@LINE+4]]:14: error: member name `C` not found in `N` [MemberNameNotFoundInScope]
+// CHECK:STDERR: fail_use_poison.carbon:[[@LINE+4]]:14: error: member name `C` not found in `N` [MemberNameNotFoundInInstScope]
 // CHECK:STDERR: fn N.F2() -> N.C;
 // CHECK:STDERR:              ^~~
 // CHECK:STDERR:
@@ -94,7 +94,7 @@ fn N.F1(x: C);
 class N.C;
 
 // Failure: `N.C` used after declaration failed.
-// CHECK:STDERR: fail_use_declaration_after_poison.carbon:[[@LINE+4]]:12: error: member name `C` not found in `N` [MemberNameNotFoundInScope]
+// CHECK:STDERR: fail_use_declaration_after_poison.carbon:[[@LINE+4]]:12: error: member name `C` not found in `N` [MemberNameNotFoundInInstScope]
 // CHECK:STDERR: fn N.F2(x: N.C);
 // CHECK:STDERR:            ^~~
 // CHECK:STDERR:
diff --git a/toolchain/check/testdata/function/declaration/no_prelude/name_poisoning.carbon b/toolchain/check/testdata/function/declaration/no_prelude/name_poisoning.carbon
index e20fdadda425..ff021d73f946 100644
--- a/toolchain/check/testdata/function/declaration/no_prelude/name_poisoning.carbon
+++ b/toolchain/check/testdata/function/declaration/no_prelude/name_poisoning.carbon
@@ -69,7 +69,7 @@ fn F1();
 namespace N;
 alias N.F2 = F1;
 
-// CHECK:STDERR: fail_use_poison.carbon:[[@LINE+4]]:14: error: member name `F1` not found in `N` [MemberNameNotFoundInScope]
+// CHECK:STDERR: fail_use_poison.carbon:[[@LINE+4]]:14: error: member name `F1` not found in `N` [MemberNameNotFoundInInstScope]
 // CHECK:STDERR: alias N.F3 = N.F1;
 // CHECK:STDERR:              ^~~~
 // CHECK:STDERR:
@@ -97,7 +97,7 @@ fn N.F1();
 
 // Failure: `N.F1` used after declaration failed.
 // TODO: #4622 - Allow defining a poisoned name so it would be found if used after it's declared.
-// CHECK:STDERR: fail_use_declaration_after_poison.carbon:[[@LINE+4]]:14: error: member name `F1` not found in `N` [MemberNameNotFoundInScope]
+// CHECK:STDERR: fail_use_declaration_after_poison.carbon:[[@LINE+4]]:14: error: member name `F1` not found in `N` [MemberNameNotFoundInInstScope]
 // CHECK:STDERR: alias N.F3 = N.F1;
 // CHECK:STDERR:              ^~~~
 // CHECK:STDERR:
diff --git a/toolchain/check/testdata/function/definition/import_access.carbon b/toolchain/check/testdata/function/definition/import_access.carbon
index fd9ded7bb48c..dab03e195478 100644
--- a/toolchain/check/testdata/function/definition/import_access.carbon
+++ b/toolchain/check/testdata/function/definition/import_access.carbon
@@ -60,7 +60,7 @@ package Other library "[[@TEST_NAME]]";
 
 import Test library "def";
 
-// CHECK:STDERR: fail_other_def.carbon:[[@LINE+4]]:13: error: member name `Def` not found in `Test` [MemberNameNotFoundInScope]
+// CHECK:STDERR: fail_other_def.carbon:[[@LINE+4]]:13: error: member name `Def` not found in `Test` [MemberNameNotFoundInInstScope]
 // CHECK:STDERR: var f: () = Test.Def();
 // CHECK:STDERR:             ^~~~~~~~
 // CHECK:STDERR:
@@ -90,7 +90,7 @@ package Other library "[[@TEST_NAME]]";
 
 import Test library "forward_with_def";
 
-// CHECK:STDERR: fail_other_forward_with_def.carbon:[[@LINE+4]]:13: error: member name `ForwardWithDef` not found in `Test` [MemberNameNotFoundInScope]
+// CHECK:STDERR: fail_other_forward_with_def.carbon:[[@LINE+4]]:13: error: member name `ForwardWithDef` not found in `Test` [MemberNameNotFoundInInstScope]
 // CHECK:STDERR: var f: () = Test.ForwardWithDef();
 // CHECK:STDERR:             ^~~~~~~~~~~~~~~~~~~
 // CHECK:STDERR:
@@ -122,7 +122,7 @@ package Other library "[[@TEST_NAME]]";
 
 import Test library "forward";
 
-// CHECK:STDERR: fail_other_forward.carbon:[[@LINE+4]]:13: error: member name `Forward` not found in `Test` [MemberNameNotFoundInScope]
+// CHECK:STDERR: fail_other_forward.carbon:[[@LINE+4]]:13: error: member name `Forward` not found in `Test` [MemberNameNotFoundInInstScope]
 // CHECK:STDERR: var f: () = Test.Forward();
 // CHECK:STDERR:             ^~~~~~~~~~~~
 // CHECK:STDERR:
diff --git a/toolchain/check/testdata/generic/template/member_access.carbon b/toolchain/check/testdata/generic/template/member_access.carbon
index a15eec9a1283..4fd6ba141079 100644
--- a/toolchain/check/testdata/generic/template/member_access.carbon
+++ b/toolchain/check/testdata/generic/template/member_access.carbon
@@ -33,7 +33,7 @@ fn Test2(x: {.m: i32, .n: i32}) {
 library "[[@TEST_NAME]]";
 
 fn F[template T:! type](x: T) -> i32 {
-  // CHECK:STDERR: fail_no_such_member.carbon:[[@LINE+3]]:10: error: member name `n` not found in `D` [MemberNameNotFoundInScope]
+  // CHECK:STDERR: fail_no_such_member.carbon:[[@LINE+3]]:10: error: member name `n` not found in `D` [MemberNameNotFoundInInstScope]
   // CHECK:STDERR:   return x.n;
   // CHECK:STDERR:          ^~~
   return x.n;
diff --git a/toolchain/check/testdata/interface/member_lookup.carbon b/toolchain/check/testdata/interface/member_lookup.carbon
index 528c8ad4e411..d082e0101c70 100644
--- a/toolchain/check/testdata/interface/member_lookup.carbon
+++ b/toolchain/check/testdata/interface/member_lookup.carbon
@@ -33,7 +33,7 @@ interface Interface(T:! type) {
 }
 
 fn AccessMissingGeneric[T:! type](I:! Interface(T)) -> T {
-  // CHECK:STDERR: fail_no_member.carbon:[[@LINE+4]]:10: error: member name `nonesuch` not found in `Interface(T)` [MemberNameNotFoundInScope]
+  // CHECK:STDERR: fail_no_member.carbon:[[@LINE+4]]:10: error: member name `nonesuch` not found in `Interface(T)` [MemberNameNotFoundInSpecificScope]
   // CHECK:STDERR:   return I.nonesuch;
   // CHECK:STDERR:          ^~~~~~~~~~
   // CHECK:STDERR:
@@ -41,7 +41,7 @@ fn AccessMissingGeneric[T:! type](I:! Interface(T)) -> T {
 }
 
 fn AccessMissingConcrete(I:! Interface(i32)) -> i32 {
-  // CHECK:STDERR: fail_no_member.carbon:[[@LINE+4]]:10: error: member name `nonesuch` not found in `Interface(i32)` [MemberNameNotFoundInScope]
+  // CHECK:STDERR: fail_no_member.carbon:[[@LINE+4]]:10: error: member name `nonesuch` not found in `Interface(i32)` [MemberNameNotFoundInSpecificScope]
   // CHECK:STDERR:   return I.nonesuch;
   // CHECK:STDERR:          ^~~~~~~~~~
   // CHECK:STDERR:
diff --git a/toolchain/check/testdata/interface/no_prelude/import_access.carbon b/toolchain/check/testdata/interface/no_prelude/import_access.carbon
index 7e46a966b92d..27656a6795d6 100644
--- a/toolchain/check/testdata/interface/no_prelude/import_access.carbon
+++ b/toolchain/check/testdata/interface/no_prelude/import_access.carbon
@@ -61,7 +61,7 @@ package Other library "[[@TEST_NAME]]";
 
 import Test library "def";
 
-// CHECK:STDERR: fail_other_def.carbon:[[@LINE+4]]:9: error: member name `Def` not found in `Test` [MemberNameNotFoundInScope]
+// CHECK:STDERR: fail_other_def.carbon:[[@LINE+4]]:9: error: member name `Def` not found in `Test` [MemberNameNotFoundInInstScope]
 // CHECK:STDERR: fn F(i: Test.Def) {}
 // CHECK:STDERR:         ^~~~~~~~
 // CHECK:STDERR:
@@ -91,7 +91,7 @@ package Other library "[[@TEST_NAME]]";
 
 import Test library "forward_with_def";
 
-// CHECK:STDERR: fail_other_forward_with_def.carbon:[[@LINE+4]]:9: error: member name `ForwardWithDef` not found in `Test` [MemberNameNotFoundInScope]
+// CHECK:STDERR: fail_other_forward_with_def.carbon:[[@LINE+4]]:9: error: member name `ForwardWithDef` not found in `Test` [MemberNameNotFoundInInstScope]
 // CHECK:STDERR: fn F(i: Test.ForwardWithDef) {}
 // CHECK:STDERR:         ^~~~~~~~~~~~~~~~~~~
 // CHECK:STDERR:
diff --git a/toolchain/check/testdata/interface/no_prelude/name_poisoning.carbon b/toolchain/check/testdata/interface/no_prelude/name_poisoning.carbon
index bb426a33453b..57255206b1f7 100644
--- a/toolchain/check/testdata/interface/no_prelude/name_poisoning.carbon
+++ b/toolchain/check/testdata/interface/no_prelude/name_poisoning.carbon
@@ -66,7 +66,7 @@ namespace N;
 // Use `package.I` and poison `N.I`.
 fn N.F1(x:! I);
 
-// CHECK:STDERR: fail_use_poison.carbon:[[@LINE+4]]:13: error: member name `I` not found in `N` [MemberNameNotFoundInScope]
+// CHECK:STDERR: fail_use_poison.carbon:[[@LINE+4]]:13: error: member name `I` not found in `N` [MemberNameNotFoundInInstScope]
 // CHECK:STDERR: fn N.F2(x:! N.I);
 // CHECK:STDERR:             ^~~
 // CHECK:STDERR:
@@ -91,7 +91,7 @@ fn N.F1(x:! I);
 // CHECK:STDERR:
 interface N.I;
 
-// CHECK:STDERR: fail_use_declaration_after_poison.carbon:[[@LINE+4]]:13: error: member name `I` not found in `N` [MemberNameNotFoundInScope]
+// CHECK:STDERR: fail_use_declaration_after_poison.carbon:[[@LINE+4]]:13: error: member name `I` not found in `N` [MemberNameNotFoundInInstScope]
 // CHECK:STDERR: fn N.F2(x:! N.I);
 // CHECK:STDERR:             ^~~
 // CHECK:STDERR:
diff --git a/toolchain/check/testdata/interop/cpp/no_prelude/function_decl.carbon b/toolchain/check/testdata/interop/cpp/no_prelude/function_decl.carbon
index 61679f6cd1f8..6751ffa56f68 100644
--- a/toolchain/check/testdata/interop/cpp/no_prelude/function_decl.carbon
+++ b/toolchain/check/testdata/interop/cpp/no_prelude/function_decl.carbon
@@ -29,7 +29,7 @@ library "[[@TEST_NAME]]";
 import Cpp library "function_decl.h";
 
 fn MyF() {
-  // CHECK:STDERR: fail_import_function_decl_use_different_name.carbon:[[@LINE+4]]:3: error: member name `bar` not found in `Cpp` [MemberNameNotFoundInScope]
+  // CHECK:STDERR: fail_import_function_decl_use_different_name.carbon:[[@LINE+4]]:3: error: member name `bar` not found in `Cpp` [MemberNameNotFoundInInstScope]
   // CHECK:STDERR:   Cpp.bar();
   // CHECK:STDERR:   ^~~~~~~
   // CHECK:STDERR:
@@ -47,7 +47,7 @@ library "[[@TEST_NAME]]";
 import Cpp library "function_special_name_decl.h";
 
 fn MyF() {
-  // CHECK:STDERR: fail_import_function_special_name_decl.carbon:[[@LINE+4]]:3: error: member name `base` not found in `Cpp` [MemberNameNotFoundInScope]
+  // CHECK:STDERR: fail_import_function_special_name_decl.carbon:[[@LINE+4]]:3: error: member name `base` not found in `Cpp` [MemberNameNotFoundInInstScope]
   // CHECK:STDERR:   Cpp.base();
   // CHECK:STDERR:   ^~~~~~~~
   // CHECK:STDERR:
diff --git a/toolchain/check/testdata/interop/cpp/no_prelude/namespace.carbon b/toolchain/check/testdata/interop/cpp/no_prelude/namespace.carbon
index 4075777617bb..cab8ae072778 100644
--- a/toolchain/check/testdata/interop/cpp/no_prelude/namespace.carbon
+++ b/toolchain/check/testdata/interop/cpp/no_prelude/namespace.carbon
@@ -53,7 +53,7 @@ library "[[@TEST_NAME]]";
 import Cpp library "namespace.h";
 
 fn MyF() {
-  // CHECK:STDERR: fail_import_namespace_wrong_name_in_namespace.carbon:[[@LINE+4]]:3: error: member name `not_foo` not found in `Cpp.my_namespace` [MemberNameNotFoundInScope]
+  // CHECK:STDERR: fail_import_namespace_wrong_name_in_namespace.carbon:[[@LINE+4]]:3: error: member name `not_foo` not found in `Cpp.my_namespace` [MemberNameNotFoundInInstScope]
   // CHECK:STDERR:   Cpp.my_namespace.not_foo();
   // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~~~~~~~
   // CHECK:STDERR:
@@ -67,7 +67,7 @@ library "[[@TEST_NAME]]";
 import Cpp library "namespace.h";
 
 fn MyF() {
-  // CHECK:STDERR: fail_import_namespace_use_different_name.carbon:[[@LINE+4]]:3: error: member name `not_my_namespace` not found in `Cpp` [MemberNameNotFoundInScope]
+  // CHECK:STDERR: fail_import_namespace_use_different_name.carbon:[[@LINE+4]]:3: error: member name `not_my_namespace` not found in `Cpp` [MemberNameNotFoundInInstScope]
   // CHECK:STDERR:   Cpp.not_my_namespace.foo();
   // CHECK:STDERR:   ^~~~~~~~~~~~~~~~~~~~
   // CHECK:STDERR:
@@ -85,7 +85,7 @@ library "[[@TEST_NAME]]";
 import Cpp library "namespace_special_name_decl.h";
 
 fn MyF() {
-  // CHECK:STDERR: fail_import_namespace_special_name_decl.carbon:[[@LINE+4]]:3: error: member name `base` not found in `Cpp` [MemberNameNotFoundInScope]
+  // CHECK:STDERR: fail_import_namespace_special_name_decl.carbon:[[@LINE+4]]:3: error: member name `base` not found in `Cpp` [MemberNameNotFoundInInstScope]
   // CHECK:STDERR:   Cpp.base.foo();
   // CHECK:STDERR:   ^~~~~~~~
   // CHECK:STDERR:
diff --git a/toolchain/check/testdata/interop/cpp/no_prelude/unsupported_decl_type.carbon b/toolchain/check/testdata/interop/cpp/no_prelude/unsupported_decl_type.carbon
index edbdc74a5349..0195eafeebaf 100644
--- a/toolchain/check/testdata/interop/cpp/no_prelude/unsupported_decl_type.carbon
+++ b/toolchain/check/testdata/interop/cpp/no_prelude/unsupported_decl_type.carbon
@@ -26,7 +26,7 @@ fn F() {
   // CHECK:STDERR:   Cpp.foo();
   // CHECK:STDERR:   ^~~~~~~
   // CHECK:STDERR:
-  // CHECK:STDERR: fail_import_unsupported_decl.carbon:[[@LINE+4]]:3: error: member name `foo` not found in `Cpp` [MemberNameNotFoundInScope]
+  // CHECK:STDERR: fail_import_unsupported_decl.carbon:[[@LINE+4]]:3: error: member name `foo` not found in `Cpp` [MemberNameNotFoundInInstScope]
   // CHECK:STDERR:   Cpp.foo();
   // CHECK:STDERR:   ^~~~~~~
   // CHECK:STDERR:
diff --git a/toolchain/check/testdata/let/no_prelude/import_access.carbon b/toolchain/check/testdata/let/no_prelude/import_access.carbon
index 51eee19d06c1..528e6ba17bae 100644
--- a/toolchain/check/testdata/let/no_prelude/import_access.carbon
+++ b/toolchain/check/testdata/let/no_prelude/import_access.carbon
@@ -46,7 +46,7 @@ package Other library "[[@TEST_NAME]]";
 
 import Test library "def";
 
-// CHECK:STDERR: fail_other_def.carbon:[[@LINE+4]]:14: error: member name `v` not found in `Test` [MemberNameNotFoundInScope]
+// CHECK:STDERR: fail_other_def.carbon:[[@LINE+4]]:14: error: member name `v` not found in `Test` [MemberNameNotFoundInInstScope]
 // CHECK:STDERR: let v2: () = Test.v;
 // CHECK:STDERR:              ^~~~~~
 // CHECK:STDERR:
diff --git a/toolchain/check/testdata/namespace/no_prelude/name_poisoning.carbon b/toolchain/check/testdata/namespace/no_prelude/name_poisoning.carbon
index 2b9e7f14a128..9f8bc4a06487 100644
--- a/toolchain/check/testdata/namespace/no_prelude/name_poisoning.carbon
+++ b/toolchain/check/testdata/namespace/no_prelude/name_poisoning.carbon
@@ -68,7 +68,7 @@ namespace N1;
 namespace N2;
 alias N2.N3 = N1;
 
-// CHECK:STDERR: fail_use_poison.carbon:[[@LINE+4]]:15: error: member name `N1` not found in `N2` [MemberNameNotFoundInScope]
+// CHECK:STDERR: fail_use_poison.carbon:[[@LINE+4]]:15: error: member name `N1` not found in `N2` [MemberNameNotFoundInInstScope]
 // CHECK:STDERR: alias N2.N4 = N2.N1;
 // CHECK:STDERR:               ^~~~~
 // CHECK:STDERR:
@@ -94,7 +94,7 @@ alias N2.N3 = N1;
 // CHECK:STDERR:
 namespace N2.N1;
 
-// CHECK:STDERR: fail_use_declaration_after_poison.carbon:[[@LINE+4]]:15: error: member name `N1` not found in `N2` [MemberNameNotFoundInScope]
+// CHECK:STDERR: fail_use_declaration_after_poison.carbon:[[@LINE+4]]:15: error: member name `N1` not found in `N2` [MemberNameNotFoundInInstScope]
 // CHECK:STDERR: alias N2.N4 = N2.N1;
 // CHECK:STDERR:               ^~~~~
 // CHECK:STDERR:
diff --git a/toolchain/check/testdata/package_expr/fail_not_found.carbon b/toolchain/check/testdata/package_expr/fail_not_found.carbon
index 4b77533a0afb..59b8074aeace 100644
--- a/toolchain/check/testdata/package_expr/fail_not_found.carbon
+++ b/toolchain/check/testdata/package_expr/fail_not_found.carbon
@@ -9,7 +9,7 @@
 // TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/package_expr/fail_not_found.carbon
 
 fn Main() {
-  // CHECK:STDERR: fail_not_found.carbon:[[@LINE+4]]:16: error: member name `x` not found in `package` [MemberNameNotFoundInScope]
+  // CHECK:STDERR: fail_not_found.carbon:[[@LINE+4]]:16: error: member name `x` not found in `package` [MemberNameNotFoundInInstScope]
   // CHECK:STDERR:   var y: i32 = package.x;
   // CHECK:STDERR:                ^~~~~~~~~
   // CHECK:STDERR:
diff --git a/toolchain/check/testdata/packages/no_prelude/cross_package_import.carbon b/toolchain/check/testdata/packages/no_prelude/cross_package_import.carbon
index 366d2181b23e..86ace6cf497d 100644
--- a/toolchain/check/testdata/packages/no_prelude/cross_package_import.carbon
+++ b/toolchain/check/testdata/packages/no_prelude/cross_package_import.carbon
@@ -201,7 +201,7 @@ library "[[@TEST_NAME]]";
 
 import Other library "other_fn_use";
 
-// CHECK:STDERR: fail_use_other_fn_use.carbon:[[@LINE+4]]:13: error: member name `F` not found in `Other` [MemberNameNotFoundInScope]
+// CHECK:STDERR: fail_use_other_fn_use.carbon:[[@LINE+4]]:13: error: member name `F` not found in `Other` [MemberNameNotFoundInInstScope]
 // CHECK:STDERR: fn UseF() { Other.F(); }
 // CHECK:STDERR:             ^~~~~~~
 // CHECK:STDERR:
diff --git a/toolchain/check/testdata/packages/raw_core.carbon b/toolchain/check/testdata/packages/raw_core.carbon
index cb27534e2c09..00006d78e108 100644
--- a/toolchain/check/testdata/packages/raw_core.carbon
+++ b/toolchain/check/testdata/packages/raw_core.carbon
@@ -30,13 +30,13 @@ library "[[@TEST_NAME]]";
 
 import r#Core;
 
-// CHECK:STDERR: fail_raw_core_not_core.carbon:[[@LINE+4]]:10: error: member name `F` not found in `Core` [MemberNameNotFoundInScope]
+// CHECK:STDERR: fail_raw_core_not_core.carbon:[[@LINE+4]]:10: error: member name `F` not found in `Core` [MemberNameNotFoundInInstScope]
 // CHECK:STDERR: fn G() { Core.F(); }
 // CHECK:STDERR:          ^~~~~~
 // CHECK:STDERR:
 fn G() { Core.F(); }
 
-// CHECK:STDERR: fail_raw_core_not_core.carbon:[[@LINE+4]]:10: error: member name `Int` not found in `r#Core` [MemberNameNotFoundInScope]
+// CHECK:STDERR: fail_raw_core_not_core.carbon:[[@LINE+4]]:10: error: member name `Int` not found in `r#Core` [MemberNameNotFoundInInstScope]
 // CHECK:STDERR: fn H() { r#Core.Int(32); }
 // CHECK:STDERR:          ^~~~~~~~~~
 // CHECK:STDERR:
diff --git a/toolchain/check/testdata/var/no_prelude/import_access.carbon b/toolchain/check/testdata/var/no_prelude/import_access.carbon
index 454cf569c7a9..4e33d4b9dfc8 100644
--- a/toolchain/check/testdata/var/no_prelude/import_access.carbon
+++ b/toolchain/check/testdata/var/no_prelude/import_access.carbon
@@ -46,7 +46,7 @@ package Other library "[[@TEST_NAME]]";
 
 import Test library "def";
 
-// CHECK:STDERR: fail_other_def.carbon:[[@LINE+4]]:14: error: member name `v` not found in `Test` [MemberNameNotFoundInScope]
+// CHECK:STDERR: fail_other_def.carbon:[[@LINE+4]]:14: error: member name `v` not found in `Test` [MemberNameNotFoundInInstScope]
 // CHECK:STDERR: var v2: () = Test.v;
 // CHECK:STDERR:              ^~~~~~
 // CHECK:STDERR:
diff --git a/toolchain/check/testdata/where_expr/designator.carbon b/toolchain/check/testdata/where_expr/designator.carbon
index 5152b706f1ba..28526523ec6f 100644
--- a/toolchain/check/testdata/where_expr/designator.carbon
+++ b/toolchain/check/testdata/where_expr/designator.carbon
@@ -30,7 +30,7 @@ interface J {
   let Member:! type;
 }
 
-// CHECK:STDERR: fail_wrong_member.carbon:[[@LINE+4]]:31: error: member name `Mismatch` not found in `J` [MemberNameNotFoundInScope]
+// CHECK:STDERR: fail_wrong_member.carbon:[[@LINE+4]]:31: error: member name `Mismatch` not found in `J` [MemberNameNotFoundInInstScope]
 // CHECK:STDERR: fn PeriodMismatch(W:! J where .Mismatch = {});
 // CHECK:STDERR:                               ^~~~~~~~~
 // CHECK:STDERR:
diff --git a/toolchain/diagnostics/diagnostic_kind.def b/toolchain/diagnostics/diagnostic_kind.def
index 4781de1d59c1..188940764576 100644
--- a/toolchain/diagnostics/diagnostic_kind.def
+++ b/toolchain/diagnostics/diagnostic_kind.def
@@ -329,7 +329,8 @@ CARBON_DIAGNOSTIC_KIND(InNameLookup)
 CARBON_DIAGNOSTIC_KIND(NameAmbiguousDueToExtend)
 CARBON_DIAGNOSTIC_KIND(NameNotFound)
 CARBON_DIAGNOSTIC_KIND(MemberNameNotFound)
-CARBON_DIAGNOSTIC_KIND(MemberNameNotFoundInScope)
+CARBON_DIAGNOSTIC_KIND(MemberNameNotFoundInInstScope)
+CARBON_DIAGNOSTIC_KIND(MemberNameNotFoundInSpecificScope)
 CARBON_DIAGNOSTIC_KIND(NoPeriodSelfForDesignator)
 CARBON_DIAGNOSTIC_KIND(UsedBeforeInitialization)
 
diff --git a/toolchain/sem_ir/ids.h b/toolchain/sem_ir/ids.h
index 0379546318c8..b6f344f4649b 100644
--- a/toolchain/sem_ir/ids.h
+++ b/toolchain/sem_ir/ids.h
@@ -301,6 +301,8 @@ struct GenericId : public IdBase<GenericId> {
 // The ID of a specific, which is the result of specifying the generic arguments
 // for a generic.
 struct SpecificId : public IdBase<SpecificId> {
+  using DiagnosticType = Diagnostics::TypeInfo<std::string>;
+
   static constexpr llvm::StringLiteral Label = "specific";
   using ValueType = Specific;
 
diff --git a/toolchain/sem_ir/stringify_type.cpp b/toolchain/sem_ir/stringify_type.cpp
index 1e322385deeb..997bd2388566 100644
--- a/toolchain/sem_ir/stringify_type.cpp
+++ b/toolchain/sem_ir/stringify_type.cpp
@@ -59,10 +59,7 @@ class StepStack {
 
   // Starts a new stack, which always contains the first instruction to
   // stringify.
-  explicit StepStack(const SemIR::File* file, InstId outer_inst_id)
-      : sem_ir_(file) {
-    PushInstId(outer_inst_id);
-  }
+  explicit StepStack(const SemIR::File* file) : sem_ir_(file) {}
 
   // These push basic entries onto the stack.
   auto PushInstId(InstId inst_id) -> void { steps_.push_back(inst_id); }
@@ -608,13 +605,10 @@ class Stringifier {
 
 }  // namespace
 
-auto StringifyTypeExpr(const SemIR::File& sem_ir, InstId outer_inst_id)
+static auto Stringify(const SemIR::File& sem_ir, StepStack& step_stack)
     -> std::string {
   RawStringOstream out;
 
-  // Note: Since this is a stack, work is resolved in the reverse order from the
-  // order pushed.
-  StepStack step_stack(&sem_ir, outer_inst_id);
   Stringifier stringifier(&sem_ir, &step_stack, &out);
 
   while (!step_stack.empty()) {
@@ -645,4 +639,60 @@ auto StringifyTypeExpr(const SemIR::File& sem_ir, InstId outer_inst_id)
   return out.TakeStr();
 }
 
+auto StringifyTypeExpr(const SemIR::File& sem_ir, InstId outer_inst_id)
+    -> std::string {
+  StepStack step_stack(&sem_ir);
+  step_stack.PushInstId(outer_inst_id);
+  return Stringify(sem_ir, step_stack);
+}
+
+auto StringifySpecific(const File& sem_ir, SpecificId specific_id)
+    -> std::string {
+  StepStack step_stack(&sem_ir);
+
+  const auto& specific = sem_ir.specifics().Get(specific_id);
+  const auto& generic = sem_ir.generics().Get(specific.generic_id);
+  auto decl = sem_ir.insts().Get(generic.decl_id);
+  CARBON_KIND_SWITCH(decl) {
+    case CARBON_KIND(SemIR::ClassDecl class_decl): {
+      // Print `Core.Int(N)` as `iN`.
+      // TODO: This duplicates work done in StringifyTypeInst for ClassType.
+      const auto& class_info = sem_ir.classes().Get(class_decl.class_id);
+      if (auto literal_info = NumericTypeLiteralInfo::ForType(
+              sem_ir,
+              SemIR::ClassType{.type_id = SemIR::TypeType::SingletonTypeId,
+                               .class_id = class_decl.class_id,
+                               .specific_id = specific_id});
+          literal_info.is_valid()) {
+        RawStringOstream out;
+        literal_info.PrintLiteral(sem_ir, out);
+        return out.TakeStr();
+      }
+      step_stack.PushEntityName(class_info, specific_id);
+      break;
+    }
+    case CARBON_KIND(SemIR::FunctionDecl function_decl): {
+      step_stack.PushEntityName(
+          sem_ir.functions().Get(function_decl.function_id), specific_id);
+      break;
+    }
+    case CARBON_KIND(SemIR::ImplDecl impl_decl): {
+      step_stack.PushEntityName(sem_ir.impls().Get(impl_decl.impl_id),
+                                specific_id);
+      break;
+    }
+    case CARBON_KIND(SemIR::InterfaceDecl interface_decl): {
+      step_stack.PushEntityName(
+          sem_ir.interfaces().Get(interface_decl.interface_id), specific_id);
+      break;
+    }
+    default: {
+      // TODO: Include the specific arguments here.
+      step_stack.PushInstId(generic.decl_id);
+      break;
+    }
+  }
+  return Stringify(sem_ir, step_stack);
+}
+
 }  // namespace Carbon::SemIR
diff --git a/toolchain/sem_ir/stringify_type.h b/toolchain/sem_ir/stringify_type.h
index 9c49a3fb6ae6..1484ea07a493 100644
--- a/toolchain/sem_ir/stringify_type.h
+++ b/toolchain/sem_ir/stringify_type.h
@@ -17,6 +17,12 @@ namespace Carbon::SemIR {
 // expression describing the type.
 auto StringifyTypeExpr(const File& sem_ir, InstId outer_inst_id) -> std::string;
 
+// Produces a string version of the name of a specific. Generally, this should
+// not be called directly. To format a string into a diagnostic, use a
+// diagnostic parameter of type `SemIR::SpecificId`.
+auto StringifySpecific(const File& sem_ir, SpecificId specific_id)
+    -> std::string;
+
 }  // namespace Carbon::SemIR
 
 #endif  // CARBON_TOOLCHAIN_SEM_IR_STRINGIFY_TYPE_H_