diff --git a/tools/aconfig/protos/aconfig.proto b/tools/aconfig/protos/aconfig.proto
index a3b1fec..9d36a9e 100644
--- a/tools/aconfig/protos/aconfig.proto
+++ b/tools/aconfig/protos/aconfig.proto
@@ -12,8 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License
 
-// This is the schema definition for of Aconfig files. Modifications need to be
-// either backwards compatible, or include updates to all Aconfig files in the
+// This is the schema definition for aconfig files. Modifications need to be
+// either backwards compatible, or include updates to all aconfig files in the
 // Android tree.
 
 syntax = "proto2";
@@ -32,40 +32,33 @@
   READ_WRITE = 2;
 }
 
-// aconfig input messages: configuration and override data
+// aconfig input messages: flag declarations and values
 
-message flag_value {
-  required flag_state state = 1;
-  required flag_permission permission = 2;
-  optional uint32 since = 3;
-}
-
-message flag_definition {
+message flag_declaration {
   required string name = 1;
   required string description = 2;
-  repeated flag_value value = 3;
 };
 
-message namespace {
+message flag_declarations {
   required string namespace = 1;
-  repeated flag_definition flag = 2;
+  repeated flag_declaration flag = 2;
 };
 
-message flag_override {
+message flag_value {
   required string namespace = 1;
   required string name = 2;
   required flag_state state = 3;
   required flag_permission permission = 4;
 };
 
-message flag_overrides {
-  repeated flag_override flag_override = 1;
+message flag_values {
+  repeated flag_value flag_value = 1;
 };
 
-// aconfig output messages: parsed and verified configuration and override data
+// aconfig output messages: parsed and verified flag declarations and values
 
 message tracepoint {
-  // path to config or override file releative to $TOP
+  // path to declaration or value file relative to $TOP
   required string source = 1;
   required flag_state state = 2;
   required flag_permission permission = 3;
diff --git a/tools/aconfig/src/aconfig.rs b/tools/aconfig/src/aconfig.rs
index 8fe82b6..b09648d 100644
--- a/tools/aconfig/src/aconfig.rs
+++ b/tools/aconfig/src/aconfig.rs
@@ -20,9 +20,8 @@
 
 use crate::cache::{Cache, Item, Tracepoint};
 use crate::protos::{
-    ProtoFlagDefinition, ProtoFlagDefinitionValue, ProtoFlagOverride, ProtoFlagOverrides,
-    ProtoFlagPermission, ProtoFlagState, ProtoNamespace, ProtoParsedFlag, ProtoParsedFlags,
-    ProtoTracepoint,
+    ProtoFlagDeclaration, ProtoFlagDeclarations, ProtoFlagPermission, ProtoFlagState,
+    ProtoFlagValue, ProtoFlagValues, ProtoParsedFlag, ProtoParsedFlags, ProtoTracepoint,
 };
 
 #[derive(Debug, PartialEq, Eq, Serialize, Deserialize, Clone, Copy)]
@@ -80,112 +79,43 @@
 }
 
 #[derive(Debug, PartialEq, Eq)]
-pub struct Value {
-    state: FlagState,
-    permission: Permission,
-    since: Option<u32>,
-}
-
-#[allow(dead_code)] // only used in unit tests
-impl Value {
-    pub fn new(state: FlagState, permission: Permission, since: u32) -> Value {
-        Value { state, permission, since: Some(since) }
-    }
-
-    pub fn default(state: FlagState, permission: Permission) -> Value {
-        Value { state, permission, since: None }
-    }
-}
-
-impl TryFrom<ProtoFlagDefinitionValue> for Value {
-    type Error = Error;
-
-    fn try_from(proto: ProtoFlagDefinitionValue) -> Result<Self, Self::Error> {
-        let Some(proto_state) = proto.state else {
-            return Err(anyhow!("missing 'state' field"));
-        };
-        let state = proto_state.try_into()?;
-        let Some(proto_permission) = proto.permission else {
-            return Err(anyhow!("missing 'permission' field"));
-        };
-        let permission = proto_permission.try_into()?;
-        Ok(Value { state, permission, since: proto.since })
-    }
-}
-
-#[derive(Debug, PartialEq, Eq)]
-pub struct Flag {
+pub struct FlagDeclaration {
     pub name: String,
     pub description: String,
-
-    // ordered by Value.since; guaranteed to contain at least one item (the default value, with
-    // since == None)
-    pub values: Vec<Value>,
 }
 
-impl Flag {
+impl FlagDeclaration {
     #[allow(dead_code)] // only used in unit tests
-    pub fn try_from_text_proto(text_proto: &str) -> Result<Flag> {
-        let proto: ProtoFlagDefinition = crate::protos::try_from_text_proto(text_proto)
+    pub fn try_from_text_proto(text_proto: &str) -> Result<FlagDeclaration> {
+        let proto: ProtoFlagDeclaration = crate::protos::try_from_text_proto(text_proto)
             .with_context(|| text_proto.to_owned())?;
         proto.try_into()
     }
-
-    pub fn resolve(&self, build_id: u32) -> (FlagState, Permission) {
-        let mut state = self.values[0].state;
-        let mut permission = self.values[0].permission;
-        for candidate in self.values.iter().skip(1) {
-            let since = candidate.since.expect("invariant: non-defaults values have Some(since)");
-            if since <= build_id {
-                state = candidate.state;
-                permission = candidate.permission;
-            }
-        }
-        (state, permission)
-    }
 }
 
-impl TryFrom<ProtoFlagDefinition> for Flag {
+impl TryFrom<ProtoFlagDeclaration> for FlagDeclaration {
     type Error = Error;
 
-    fn try_from(proto: ProtoFlagDefinition) -> Result<Self, Self::Error> {
+    fn try_from(proto: ProtoFlagDeclaration) -> Result<Self, Self::Error> {
         let Some(name) = proto.name else {
             return Err(anyhow!("missing 'name' field"));
         };
         let Some(description) = proto.description else {
             return Err(anyhow!("missing 'description' field"));
         };
-        if proto.value.is_empty() {
-            return Err(anyhow!("missing 'value' field"));
-        }
-
-        let mut values: Vec<Value> = vec![];
-        for proto_value in proto.value.into_iter() {
-            let v: Value = proto_value.try_into()?;
-            if values.iter().any(|w| v.since == w.since) {
-                let msg = match v.since {
-                    None => format!("flag {}: multiple default values", name),
-                    Some(x) => format!("flag {}: multiple values for since={}", name, x),
-                };
-                return Err(anyhow!(msg));
-            }
-            values.push(v);
-        }
-        values.sort_by_key(|v| v.since);
-
-        Ok(Flag { name, description, values })
+        Ok(FlagDeclaration { name, description })
     }
 }
 
 #[derive(Debug, PartialEq, Eq)]
-pub struct Namespace {
+pub struct FlagDeclarations {
     pub namespace: String,
-    pub flags: Vec<Flag>,
+    pub flags: Vec<FlagDeclaration>,
 }
 
-impl Namespace {
-    pub fn try_from_text_proto(text_proto: &str) -> Result<Namespace> {
-        let proto: ProtoNamespace = crate::protos::try_from_text_proto(text_proto)
+impl FlagDeclarations {
+    pub fn try_from_text_proto(text_proto: &str) -> Result<FlagDeclarations> {
+        let proto: ProtoFlagDeclarations = crate::protos::try_from_text_proto(text_proto)
             .with_context(|| text_proto.to_owned())?;
         let Some(namespace) = proto.namespace else {
             return Err(anyhow!("missing 'namespace' field"));
@@ -194,35 +124,35 @@
         for proto_flag in proto.flag.into_iter() {
             flags.push(proto_flag.try_into()?);
         }
-        Ok(Namespace { namespace, flags })
+        Ok(FlagDeclarations { namespace, flags })
     }
 }
 
 #[derive(Debug, PartialEq, Eq)]
-pub struct Override {
+pub struct FlagValue {
     pub namespace: String,
     pub name: String,
     pub state: FlagState,
     pub permission: Permission,
 }
 
-impl Override {
+impl FlagValue {
     #[allow(dead_code)] // only used in unit tests
-    pub fn try_from_text_proto(text_proto: &str) -> Result<Override> {
-        let proto: ProtoFlagOverride = crate::protos::try_from_text_proto(text_proto)?;
+    pub fn try_from_text_proto(text_proto: &str) -> Result<FlagValue> {
+        let proto: ProtoFlagValue = crate::protos::try_from_text_proto(text_proto)?;
         proto.try_into()
     }
 
-    pub fn try_from_text_proto_list(text_proto: &str) -> Result<Vec<Override>> {
-        let proto: ProtoFlagOverrides = crate::protos::try_from_text_proto(text_proto)?;
-        proto.flag_override.into_iter().map(|proto_flag| proto_flag.try_into()).collect()
+    pub fn try_from_text_proto_list(text_proto: &str) -> Result<Vec<FlagValue>> {
+        let proto: ProtoFlagValues = crate::protos::try_from_text_proto(text_proto)?;
+        proto.flag_value.into_iter().map(|proto_flag| proto_flag.try_into()).collect()
     }
 }
 
-impl TryFrom<ProtoFlagOverride> for Override {
+impl TryFrom<ProtoFlagValue> for FlagValue {
     type Error = Error;
 
-    fn try_from(proto: ProtoFlagOverride) -> Result<Self, Self::Error> {
+    fn try_from(proto: ProtoFlagValue) -> Result<Self, Self::Error> {
         let Some(namespace) = proto.namespace else {
             return Err(anyhow!("missing 'namespace' field"));
         };
@@ -237,7 +167,7 @@
             return Err(anyhow!("missing 'permission' field"));
         };
         let permission = proto_permission.try_into()?;
-        Ok(Override { namespace, name, state, permission })
+        Ok(FlagValue { namespace, name, state, permission })
     }
 }
 
@@ -282,29 +212,16 @@
 
     #[test]
     fn test_flag_try_from_text_proto() {
-        let expected = Flag {
+        let expected = FlagDeclaration {
             name: "1234".to_owned(),
             description: "Description of the flag".to_owned(),
-            values: vec![
-                Value::default(FlagState::Disabled, Permission::ReadOnly),
-                Value::new(FlagState::Enabled, Permission::ReadWrite, 8),
-            ],
         };
 
         let s = r#"
         name: "1234"
         description: "Description of the flag"
-        value {
-            state: DISABLED
-            permission: READ_ONLY
-        }
-        value {
-            state: ENABLED
-            permission: READ_WRITE
-            since: 8
-        }
         "#;
-        let actual = Flag::try_from_text_proto(s).unwrap();
+        let actual = FlagDeclaration::try_from_text_proto(s).unwrap();
 
         assert_eq!(expected, actual);
     }
@@ -313,52 +230,24 @@
     fn test_flag_try_from_text_proto_bad_input() {
         let s = r#"
         name: "a"
-        description: "Description of the flag"
         "#;
-        let error = Flag::try_from_text_proto(s).unwrap_err();
-        assert_eq!(format!("{:?}", error), "missing 'value' field");
-
-        let s = r#"
-        description: "Description of the flag"
-        value {
-            state: ENABLED
-            permission: READ_ONLY
-        }
-        "#;
-        let error = Flag::try_from_text_proto(s).unwrap_err();
+        let error = FlagDeclaration::try_from_text_proto(s).unwrap_err();
         assert!(format!("{:?}", error).contains("Message not initialized"));
 
         let s = r#"
-        name: "a"
         description: "Description of the flag"
-        value {
-            state: ENABLED
-            permission: READ_ONLY
-        }
-        value {
-            state: ENABLED
-            permission: READ_ONLY
-        }
         "#;
-        let error = Flag::try_from_text_proto(s).unwrap_err();
-        assert_eq!(format!("{:?}", error), "flag a: multiple default values");
+        let error = FlagDeclaration::try_from_text_proto(s).unwrap_err();
+        assert!(format!("{:?}", error).contains("Message not initialized"));
     }
 
     #[test]
     fn test_namespace_try_from_text_proto() {
-        let expected = Namespace {
+        let expected = FlagDeclarations {
             namespace: "ns".to_owned(),
             flags: vec![
-                Flag {
-                    name: "a".to_owned(),
-                    description: "A".to_owned(),
-                    values: vec![Value::default(FlagState::Enabled, Permission::ReadOnly)],
-                },
-                Flag {
-                    name: "b".to_owned(),
-                    description: "B".to_owned(),
-                    values: vec![Value::default(FlagState::Disabled, Permission::ReadWrite)],
-                },
+                FlagDeclaration { name: "a".to_owned(), description: "A".to_owned() },
+                FlagDeclaration { name: "b".to_owned(), description: "B".to_owned() },
             ],
         };
 
@@ -367,28 +256,20 @@
         flag {
             name: "a"
             description: "A"
-            value {
-                state: ENABLED
-                permission: READ_ONLY
-            }
         }
         flag {
             name: "b"
             description: "B"
-            value {
-                state: DISABLED
-                permission: READ_WRITE
-            }
         }
         "#;
-        let actual = Namespace::try_from_text_proto(s).unwrap();
+        let actual = FlagDeclarations::try_from_text_proto(s).unwrap();
 
         assert_eq!(expected, actual);
     }
 
     #[test]
-    fn test_override_try_from_text_proto_list() {
-        let expected = Override {
+    fn test_flag_declaration_try_from_text_proto_list() {
+        let expected = FlagValue {
             namespace: "ns".to_owned(),
             name: "1234".to_owned(),
             state: FlagState::Enabled,
@@ -401,32 +282,8 @@
         state: ENABLED
         permission: READ_ONLY
         "#;
-        let actual = Override::try_from_text_proto(s).unwrap();
+        let actual = FlagValue::try_from_text_proto(s).unwrap();
 
         assert_eq!(expected, actual);
     }
-
-    #[test]
-    fn test_flag_resolve() {
-        let flag = Flag {
-            name: "a".to_owned(),
-            description: "A".to_owned(),
-            values: vec![
-                Value::default(FlagState::Disabled, Permission::ReadOnly),
-                Value::new(FlagState::Disabled, Permission::ReadWrite, 10),
-                Value::new(FlagState::Enabled, Permission::ReadOnly, 20),
-                Value::new(FlagState::Enabled, Permission::ReadWrite, 30),
-            ],
-        };
-        assert_eq!((FlagState::Disabled, Permission::ReadOnly), flag.resolve(0));
-        assert_eq!((FlagState::Disabled, Permission::ReadOnly), flag.resolve(9));
-        assert_eq!((FlagState::Disabled, Permission::ReadWrite), flag.resolve(10));
-        assert_eq!((FlagState::Disabled, Permission::ReadWrite), flag.resolve(11));
-        assert_eq!((FlagState::Disabled, Permission::ReadWrite), flag.resolve(19));
-        assert_eq!((FlagState::Enabled, Permission::ReadOnly), flag.resolve(20));
-        assert_eq!((FlagState::Enabled, Permission::ReadOnly), flag.resolve(21));
-        assert_eq!((FlagState::Enabled, Permission::ReadOnly), flag.resolve(29));
-        assert_eq!((FlagState::Enabled, Permission::ReadWrite), flag.resolve(30));
-        assert_eq!((FlagState::Enabled, Permission::ReadWrite), flag.resolve(10_000));
-    }
 }
diff --git a/tools/aconfig/src/cache.rs b/tools/aconfig/src/cache.rs
index 4b46c42..3ecadc9 100644
--- a/tools/aconfig/src/cache.rs
+++ b/tools/aconfig/src/cache.rs
@@ -14,13 +14,16 @@
  * limitations under the License.
  */
 
-use anyhow::{anyhow, Result};
+use anyhow::{anyhow, bail, ensure, Result};
 use serde::{Deserialize, Serialize};
 use std::io::{Read, Write};
 
-use crate::aconfig::{Flag, FlagState, Override, Permission};
+use crate::aconfig::{FlagDeclaration, FlagState, FlagValue, Permission};
 use crate::commands::Source;
 
+const DEFAULT_FLAG_STATE: FlagState = FlagState::Disabled;
+const DEFAULT_FLAG_PERMISSION: Permission = Permission::ReadWrite;
+
 #[derive(Serialize, Deserialize, Debug)]
 pub struct Tracepoint {
     pub source: Source,
@@ -44,14 +47,13 @@
 
 #[derive(Serialize, Deserialize, Debug)]
 pub struct Cache {
-    build_id: u32,
     namespace: String,
     items: Vec<Item>,
 }
 
 impl Cache {
-    pub fn new(build_id: u32, namespace: String) -> Cache {
-        Cache { build_id, namespace, items: vec![] }
+    pub fn new(namespace: String) -> Cache {
+        Cache { namespace, items: vec![] }
     }
 
     pub fn read_from_reader(reader: impl Read) -> Result<Cache> {
@@ -62,40 +64,51 @@
         serde_json::to_writer(writer, self).map_err(|e| e.into())
     }
 
-    pub fn add_flag(&mut self, source: Source, flag: Flag) -> Result<()> {
-        if self.items.iter().any(|item| item.name == flag.name) {
+    pub fn add_flag_declaration(
+        &mut self,
+        source: Source,
+        declaration: FlagDeclaration,
+    ) -> Result<()> {
+        if self.items.iter().any(|item| item.name == declaration.name) {
             return Err(anyhow!(
-                "failed to add flag {} from {}: flag already defined",
-                flag.name,
+                "failed to declare flag {} from {}: flag already declared",
+                declaration.name,
                 source,
             ));
         }
-        let (state, permission) = flag.resolve(self.build_id);
         self.items.push(Item {
             namespace: self.namespace.clone(),
-            name: flag.name.clone(),
-            description: flag.description,
-            state,
-            permission,
-            trace: vec![Tracepoint { source, state, permission }],
+            name: declaration.name.clone(),
+            description: declaration.description,
+            state: DEFAULT_FLAG_STATE,
+            permission: DEFAULT_FLAG_PERMISSION,
+            trace: vec![Tracepoint {
+                source,
+                state: DEFAULT_FLAG_STATE,
+                permission: DEFAULT_FLAG_PERMISSION,
+            }],
         });
         Ok(())
     }
 
-    pub fn add_override(&mut self, source: Source, override_: Override) -> Result<()> {
-        if override_.namespace != self.namespace {
-            // TODO: print warning?
-            return Ok(());
-        }
-        let Some(existing_item) = self.items.iter_mut().find(|item| item.name == override_.name) else {
-            return Err(anyhow!("failed to override flag {}: unknown flag", override_.name));
+    pub fn add_flag_value(&mut self, source: Source, value: FlagValue) -> Result<()> {
+        ensure!(
+            value.namespace == self.namespace,
+            "failed to set values for flag {}/{} from {}: expected namespace {}",
+            value.namespace,
+            value.name,
+            source,
+            self.namespace
+        );
+        let Some(existing_item) = self.items.iter_mut().find(|item| item.name == value.name) else {
+            bail!("failed to set values for flag {}/{} from {}: flag not declared", value.namespace, value.name, source);
         };
-        existing_item.state = override_.state;
-        existing_item.permission = override_.permission;
+        existing_item.state = value.state;
+        existing_item.permission = value.permission;
         existing_item.trace.push(Tracepoint {
             source,
-            state: override_.state,
-            permission: override_.permission,
+            state: value.state,
+            permission: value.permission,
         });
         Ok(())
     }
@@ -112,49 +125,41 @@
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::aconfig::{FlagState, Permission, Value};
+    use crate::aconfig::{FlagState, Permission};
 
     #[test]
-    fn test_add_flag() {
-        let mut cache = Cache::new(1, "ns".to_string());
+    fn test_add_flag_declaration() {
+        let mut cache = Cache::new("ns".to_string());
         cache
-            .add_flag(
+            .add_flag_declaration(
                 Source::File("first.txt".to_string()),
-                Flag {
-                    name: "foo".to_string(),
-                    description: "desc".to_string(),
-                    values: vec![Value::default(FlagState::Enabled, Permission::ReadOnly)],
-                },
+                FlagDeclaration { name: "foo".to_string(), description: "desc".to_string() },
             )
             .unwrap();
         let error = cache
-            .add_flag(
+            .add_flag_declaration(
                 Source::File("second.txt".to_string()),
-                Flag {
-                    name: "foo".to_string(),
-                    description: "desc".to_string(),
-                    values: vec![Value::default(FlagState::Disabled, Permission::ReadOnly)],
-                },
+                FlagDeclaration { name: "foo".to_string(), description: "desc".to_string() },
             )
             .unwrap_err();
         assert_eq!(
             &format!("{:?}", error),
-            "failed to add flag foo from second.txt: flag already defined"
+            "failed to declare flag foo from second.txt: flag already declared"
         );
     }
 
     #[test]
-    fn test_add_override() {
+    fn test_add_flag_value() {
         fn check(cache: &Cache, name: &str, expected: (FlagState, Permission)) -> bool {
             let item = cache.iter().find(|&item| item.name == name).unwrap();
             item.state == expected.0 && item.permission == expected.1
         }
 
-        let mut cache = Cache::new(1, "ns".to_string());
+        let mut cache = Cache::new("ns".to_string());
         let error = cache
-            .add_override(
+            .add_flag_value(
                 Source::Memory,
-                Override {
+                FlagValue {
                     namespace: "ns".to_string(),
                     name: "foo".to_string(),
                     state: FlagState::Enabled,
@@ -162,39 +167,36 @@
                 },
             )
             .unwrap_err();
-        assert_eq!(&format!("{:?}", error), "failed to override flag foo: unknown flag");
+        assert_eq!(
+            &format!("{:?}", error),
+            "failed to set values for flag ns/foo from <memory>: flag not declared"
+        );
 
         cache
-            .add_flag(
+            .add_flag_declaration(
                 Source::File("first.txt".to_string()),
-                Flag {
-                    name: "foo".to_string(),
-                    description: "desc".to_string(),
-                    values: vec![Value::default(FlagState::Enabled, Permission::ReadOnly)],
-                },
+                FlagDeclaration { name: "foo".to_string(), description: "desc".to_string() },
             )
             .unwrap();
-        dbg!(&cache);
-        assert!(check(&cache, "foo", (FlagState::Enabled, Permission::ReadOnly)));
+        assert!(check(&cache, "foo", (DEFAULT_FLAG_STATE, DEFAULT_FLAG_PERMISSION)));
 
         cache
-            .add_override(
+            .add_flag_value(
                 Source::Memory,
-                Override {
+                FlagValue {
                     namespace: "ns".to_string(),
                     name: "foo".to_string(),
                     state: FlagState::Disabled,
-                    permission: Permission::ReadWrite,
+                    permission: Permission::ReadOnly,
                 },
             )
             .unwrap();
-        dbg!(&cache);
-        assert!(check(&cache, "foo", (FlagState::Disabled, Permission::ReadWrite)));
+        assert!(check(&cache, "foo", (FlagState::Disabled, Permission::ReadOnly)));
 
         cache
-            .add_override(
+            .add_flag_value(
                 Source::Memory,
-                Override {
+                FlagValue {
                     namespace: "ns".to_string(),
                     name: "foo".to_string(),
                     state: FlagState::Enabled,
@@ -205,17 +207,18 @@
         assert!(check(&cache, "foo", (FlagState::Enabled, Permission::ReadWrite)));
 
         // different namespace -> no-op
-        cache
-            .add_override(
+        let error = cache
+            .add_flag_value(
                 Source::Memory,
-                Override {
+                FlagValue {
                     namespace: "some-other-namespace".to_string(),
                     name: "foo".to_string(),
                     state: FlagState::Enabled,
                     permission: Permission::ReadOnly,
                 },
             )
-            .unwrap();
+            .unwrap_err();
+        assert_eq!(&format!("{:?}", error), "failed to set values for flag some-other-namespace/foo from <memory>: expected namespace ns");
         assert!(check(&cache, "foo", (FlagState::Enabled, Permission::ReadWrite)));
     }
 }
diff --git a/tools/aconfig/src/codegen_java.rs b/tools/aconfig/src/codegen_java.rs
index 9d52cce..08b762a 100644
--- a/tools/aconfig/src/codegen_java.rs
+++ b/tools/aconfig/src/codegen_java.rs
@@ -87,30 +87,39 @@
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::aconfig::{Flag, Value};
+    use crate::aconfig::{FlagDeclaration, FlagValue};
     use crate::commands::Source;
 
     #[test]
     fn test_generate_java_code() {
         let namespace = "TeSTFlaG";
-        let mut cache = Cache::new(1, namespace.to_string());
+        let mut cache = Cache::new(namespace.to_string());
         cache
-            .add_flag(
+            .add_flag_declaration(
                 Source::File("test.txt".to_string()),
-                Flag {
+                FlagDeclaration {
                     name: "test".to_string(),
                     description: "buildtime enable".to_string(),
-                    values: vec![Value::default(FlagState::Enabled, Permission::ReadOnly)],
                 },
             )
             .unwrap();
         cache
-            .add_flag(
+            .add_flag_declaration(
                 Source::File("test2.txt".to_string()),
-                Flag {
+                FlagDeclaration {
                     name: "test2".to_string(),
                     description: "runtime disable".to_string(),
-                    values: vec![Value::default(FlagState::Disabled, Permission::ReadWrite)],
+                },
+            )
+            .unwrap();
+        cache
+            .add_flag_value(
+                Source::Memory,
+                FlagValue {
+                    namespace: namespace.to_string(),
+                    name: "test".to_string(),
+                    state: FlagState::Disabled,
+                    permission: Permission::ReadOnly,
                 },
             )
             .unwrap();
@@ -121,7 +130,7 @@
         public final class Testflag {
 
             public static boolean test() {
-                return true;
+                return false;
             }
 
             public static boolean test2() {
diff --git a/tools/aconfig/src/commands.rs b/tools/aconfig/src/commands.rs
index 1487e72..c02fe07 100644
--- a/tools/aconfig/src/commands.rs
+++ b/tools/aconfig/src/commands.rs
@@ -21,7 +21,7 @@
 use std::fmt;
 use std::io::Read;
 
-use crate::aconfig::{Namespace, Override};
+use crate::aconfig::{FlagDeclarations, FlagValue};
 use crate::cache::Cache;
 use crate::codegen_java::{generate_java_code, GeneratedFile};
 use crate::protos::ProtoParsedFlags;
@@ -48,37 +48,37 @@
 }
 
 pub fn create_cache(
-    build_id: u32,
     namespace: &str,
-    aconfigs: Vec<Input>,
-    overrides: Vec<Input>,
+    declarations: Vec<Input>,
+    values: Vec<Input>,
 ) -> Result<Cache> {
-    let mut cache = Cache::new(build_id, namespace.to_owned());
+    let mut cache = Cache::new(namespace.to_owned());
 
-    for mut input in aconfigs {
+    for mut input in declarations {
         let mut contents = String::new();
         input.reader.read_to_string(&mut contents)?;
-        let ns = Namespace::try_from_text_proto(&contents)
+        let dec_list = FlagDeclarations::try_from_text_proto(&contents)
             .with_context(|| format!("Failed to parse {}", input.source))?;
         ensure!(
-            namespace == ns.namespace,
+            namespace == dec_list.namespace,
             "Failed to parse {}: expected namespace {}, got {}",
             input.source,
             namespace,
-            ns.namespace
+            dec_list.namespace
         );
-        for flag in ns.flags.into_iter() {
-            cache.add_flag(input.source.clone(), flag)?;
+        for d in dec_list.flags.into_iter() {
+            cache.add_flag_declaration(input.source.clone(), d)?;
         }
     }
 
-    for mut input in overrides {
+    for mut input in values {
         let mut contents = String::new();
         input.reader.read_to_string(&mut contents)?;
-        let overrides = Override::try_from_text_proto_list(&contents)
+        let values_list = FlagValue::try_from_text_proto_list(&contents)
             .with_context(|| format!("Failed to parse {}", input.source))?;
-        for override_ in overrides {
-            cache.add_override(input.source.clone(), override_)?;
+        for v in values_list {
+            // TODO: warn about flag values that do not take effect?
+            let _ = cache.add_flag_value(input.source.clone(), v);
         }
     }
 
@@ -132,31 +132,23 @@
         flag {
             name: "a"
             description: "Description of a"
-            value {
-                state: ENABLED
-                permission: READ_WRITE
-            }
         }
         flag {
             name: "b"
             description: "Description of b"
-            value {
-                state: ENABLED
-                permission: READ_ONLY
-            }
         }
         "#;
-        let aconfigs = vec![Input { source: Source::Memory, reader: Box::new(s.as_bytes()) }];
+        let declarations = vec![Input { source: Source::Memory, reader: Box::new(s.as_bytes()) }];
         let o = r#"
-        flag_override {
+        flag_value {
             namespace: "ns"
             name: "a"
             state: DISABLED
             permission: READ_ONLY
         }
         "#;
-        let overrides = vec![Input { source: Source::Memory, reader: Box::new(o.as_bytes()) }];
-        create_cache(1, "ns", aconfigs, overrides).unwrap()
+        let values = vec![Input { source: Source::Memory, reader: Box::new(o.as_bytes()) }];
+        create_cache("ns", declarations, values).unwrap()
     }
 
     #[test]
@@ -194,12 +186,12 @@
         assert_eq!(item.namespace(), "ns");
         assert_eq!(item.name(), "b");
         assert_eq!(item.description(), "Description of b");
-        assert_eq!(item.state(), ProtoFlagState::ENABLED);
-        assert_eq!(item.permission(), ProtoFlagPermission::READ_ONLY);
+        assert_eq!(item.state(), ProtoFlagState::DISABLED);
+        assert_eq!(item.permission(), ProtoFlagPermission::READ_WRITE);
         let mut tp = ProtoTracepoint::new();
         tp.set_source("<memory>".to_string());
-        tp.set_state(ProtoFlagState::ENABLED);
-        tp.set_permission(ProtoFlagPermission::READ_ONLY);
+        tp.set_state(ProtoFlagState::DISABLED);
+        tp.set_permission(ProtoFlagPermission::READ_WRITE);
         assert_eq!(item.trace, vec![tp]);
     }
 }
diff --git a/tools/aconfig/src/main.rs b/tools/aconfig/src/main.rs
index f29186a..4abcb90 100644
--- a/tools/aconfig/src/main.rs
+++ b/tools/aconfig/src/main.rs
@@ -36,15 +36,9 @@
         .subcommand_required(true)
         .subcommand(
             Command::new("create-cache")
-                .arg(
-                    Arg::new("build-id")
-                        .long("build-id")
-                        .value_parser(clap::value_parser!(u32))
-                        .required(true),
-                )
                 .arg(Arg::new("namespace").long("namespace").required(true))
-                .arg(Arg::new("aconfig").long("aconfig").action(ArgAction::Append))
-                .arg(Arg::new("override").long("override").action(ArgAction::Append))
+                .arg(Arg::new("declarations").long("declarations").action(ArgAction::Append))
+                .arg(Arg::new("values").long("values").action(ArgAction::Append))
                 .arg(Arg::new("cache").long("cache").required(true)),
         )
         .subcommand(
@@ -78,11 +72,10 @@
     let matches = cli().get_matches();
     match matches.subcommand() {
         Some(("create-cache", sub_matches)) => {
-            let build_id = *sub_matches.get_one::<u32>("build-id").unwrap();
             let namespace = sub_matches.get_one::<String>("namespace").unwrap();
-            let aconfigs = open_zero_or_more_files(sub_matches, "aconfig")?;
-            let overrides = open_zero_or_more_files(sub_matches, "override")?;
-            let cache = commands::create_cache(build_id, namespace, aconfigs, overrides)?;
+            let declarations = open_zero_or_more_files(sub_matches, "declarations")?;
+            let values = open_zero_or_more_files(sub_matches, "values")?;
+            let cache = commands::create_cache(namespace, declarations, values)?;
             let path = sub_matches.get_one::<String>("cache").unwrap();
             let file = fs::File::create(path)?;
             cache.write_to_writer(file)?;
diff --git a/tools/aconfig/src/protos.rs b/tools/aconfig/src/protos.rs
index 5965a09..cb75692 100644
--- a/tools/aconfig/src/protos.rs
+++ b/tools/aconfig/src/protos.rs
@@ -28,19 +28,16 @@
 
 // ---- When building with the Android tool-chain ----
 #[cfg(not(feature = "cargo"))]
-pub use aconfig_protos::aconfig::Namespace as ProtoNamespace;
+pub use aconfig_protos::aconfig::Flag_declaration as ProtoFlagDeclaration;
 
 #[cfg(not(feature = "cargo"))]
-pub use aconfig_protos::aconfig::Flag_value as ProtoFlagDefinitionValue;
+pub use aconfig_protos::aconfig::Flag_declarations as ProtoFlagDeclarations;
 
 #[cfg(not(feature = "cargo"))]
-pub use aconfig_protos::aconfig::Flag_definition as ProtoFlagDefinition;
+pub use aconfig_protos::aconfig::Flag_value as ProtoFlagValue;
 
 #[cfg(not(feature = "cargo"))]
-pub use aconfig_protos::aconfig::Flag_overrides as ProtoFlagOverrides;
-
-#[cfg(not(feature = "cargo"))]
-pub use aconfig_protos::aconfig::Flag_override as ProtoFlagOverride;
+pub use aconfig_protos::aconfig::Flag_values as ProtoFlagValues;
 
 #[cfg(not(feature = "cargo"))]
 pub use aconfig_protos::aconfig::Flag_permission as ProtoFlagPermission;
@@ -62,19 +59,16 @@
 include!(concat!(env!("OUT_DIR"), "/aconfig_proto/mod.rs"));
 
 #[cfg(feature = "cargo")]
-pub use aconfig::Namespace as ProtoNamespace;
+pub use aconfig::Flag_declaration as ProtoFlagDeclaration;
 
 #[cfg(feature = "cargo")]
-pub use aconfig::Flag_value as ProtoFlagDefinitionValue;
+pub use aconfig::Flag_declarations as ProtoFlagDeclarations;
 
 #[cfg(feature = "cargo")]
-pub use aconfig::Flag_definition as ProtoFlagDefinition;
+pub use aconfig::Flag_value as ProtoFlagValue;
 
 #[cfg(feature = "cargo")]
-pub use aconfig::Flag_overrides as ProtoFlagOverrides;
-
-#[cfg(feature = "cargo")]
-pub use aconfig::Flag_override as ProtoFlagOverride;
+pub use aconfig::Flag_values as ProtoFlagValues;
 
 #[cfg(feature = "cargo")]
 pub use aconfig::Flag_permission as ProtoFlagPermission;