diff --git a/src/cli.rs b/src/cli.rs
index 58ff52d..1e5f4de 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -23,7 +23,7 @@ enum Commands {
         query: String,
         #[arg(long, help = "Filter by source id or label")]
         source: Option<String>,
-        #[arg(long, help = "Filter by time range")]
+        #[arg(long, value_parser = crate::query::parse_time_range_arg, help = "Filter by time range")]
         time: Option<String>,
         #[arg(long, help = "Filter by project directory, including child paths")]
         project: Option<String>,
@@ -62,14 +62,14 @@ enum Commands {
         json: bool,
         #[arg(long, help = "Filter by source id or label")]
         source: Option<String>,
-        #[arg(long, help = "Filter by time range")]
+        #[arg(long, value_parser = crate::query::parse_time_range_arg, help = "Filter by time range")]
         time: Option<String>,
     },
     #[command(about = "Export session records as JSON Lines")]
     Export {
         #[arg(long, help = "Filter by source id or label")]
         source: Option<String>,
-        #[arg(long, help = "Filter by time range")]
+        #[arg(long, value_parser = crate::query::parse_time_range_arg, help = "Filter by time range")]
         time: Option<String>,
         #[arg(long, help = "Filter by project directory, including child paths")]
         project: Option<String>,
@@ -387,6 +387,27 @@ mod tests {
         assert!(Cli::try_parse_from(["recall", "export", "--jsonl"]).is_err());
     }
 
+    #[test]
+    fn time_filter_validates_values_for_every_command() {
+        let commands: &[&[&str]] = &[
+            &["recall", "search", "query", "--time", "definitely-invalid"],
+            &["recall", "session", "list", "--time", "definitely-invalid"],
+            &["recall", "usage", "--time", "definitely-invalid"],
+            &["recall", "export", "--time", "definitely-invalid"],
+        ];
+
+        for args in commands {
+            let Err(error) = Cli::try_parse_from(*args) else {
+                panic!("accepted invalid --time for {}", args[1]);
+            };
+            assert_eq!(error.exit_code(), 2);
+        }
+
+        for value in ["today", "7d", "week", "30d", "month", "all", "WEEK"] {
+            assert!(Cli::try_parse_from(["recall", "usage", "--time", value]).is_ok());
+        }
+    }
+
     #[test]
     fn info_accepts_json_format() {
         let cli = Cli::try_parse_from(["recall", "info", "--format", "json"]).unwrap();
diff --git a/src/export.rs b/src/export.rs
index 00be013..6bb2982 100644
--- a/src/export.rs
+++ b/src/export.rs
@@ -48,13 +48,14 @@ pub(crate) fn run_cli(
     limit: usize,
     include_filter: Option<&str>,
 ) -> Result<()> {
+    let time_range = parse_time_range(time_filter)?;
     let store = Store::open()?;
     let sources = adapters::source_labels();
     let scope = store.resolve_scope(project_filter, repo_filter)?.announce();
     let options = ExportOptions {
         session_ids: Vec::new(),
         sources: resolve_source_filter(source_filter, &sources)?,
-        time_range: parse_time_range(time_filter),
+        time_range,
         scope,
         thread_role,
         limit: if limit == 0 { None } else { Some(limit) },
diff --git a/src/query.rs b/src/query.rs
index d81802a..7ab38ce 100644
--- a/src/query.rs
+++ b/src/query.rs
@@ -39,11 +39,11 @@ pub(crate) fn run_search(
         );
     }
 
+    let time_range = parse_time_range(time_filter)?;
     let store = Store::open()?;
     let engine = SearchEngine::new(&store.conn);
     let sources = adapters::source_labels();
     let resolved_source = resolve_source_filter(source_filter, &sources)?;
-    let time_range = parse_time_range(time_filter);
     let scope = store.resolve_scope(project_filter, repo_filter)?.announce();
     let embedding = query_embedding(&store, query, |message| println!("{message}"))?;
 
@@ -98,12 +98,22 @@ pub(crate) fn resolve_source_filter(
     Ok(Some(vec![resolved]))
 }
 
-pub(crate) fn parse_time_range(time_filter: Option<&str>) -> TimeRange {
-    match time_filter.map(|t| t.to_lowercase()) {
-        Some(ref t) if t == "today" => TimeRange::Today,
-        Some(ref t) if t == "7d" || t == "week" => TimeRange::Week,
-        Some(ref t) if t == "30d" || t == "month" => TimeRange::Month,
-        _ => TimeRange::All,
+pub(crate) fn parse_time_range_arg(value: &str) -> std::result::Result<String, String> {
+    parse_time_range(Some(value)).map(|_| value.to_owned()).map_err(|error| error.to_string())
+}
+
+pub(crate) fn parse_time_range(time_filter: Option<&str>) -> Result<TimeRange> {
+    let Some(value) = time_filter else {
+        return Ok(TimeRange::All);
+    };
+    match value.to_lowercase().as_str() {
+        "today" => Ok(TimeRange::Today),
+        "7d" | "week" => Ok(TimeRange::Week),
+        "30d" | "month" => Ok(TimeRange::Month),
+        "all" => Ok(TimeRange::All),
+        _ => anyhow::bail!(
+            "unknown time range: {value}; expected today, 7d, week, 30d, month, or all"
+        ),
     }
 }
 
diff --git a/src/session.rs b/src/session.rs
index 1f7e2eb..1940ac2 100644
--- a/src/session.rs
+++ b/src/session.rs
@@ -24,7 +24,7 @@ pub(crate) enum SessionCommands {
         query: Option<String>,
         #[arg(long, help = "Filter by source id or label")]
         source: Option<String>,
-        #[arg(long, help = "Filter by time range")]
+        #[arg(long, value_parser = crate::query::parse_time_range_arg, help = "Filter by time range")]
         time: Option<String>,
         #[arg(long, help = "Filter by project directory, including child paths")]
         project: Option<String>,
@@ -326,7 +326,7 @@ pub(crate) fn run_session_list(
 
     let sources = adapters::source_labels();
     let resolved_source = resolve_source_filter(source_filter, &sources)?;
-    let time_range = parse_time_range(time_filter);
+    let time_range = parse_time_range(time_filter)?;
 
     let store = Store::open()?;
     let scope = store.resolve_scope(project_filter, repo_filter)?.announce();
diff --git a/src/usage.rs b/src/usage.rs
index cb9f086..c56d97c 100644
--- a/src/usage.rs
+++ b/src/usage.rs
@@ -23,20 +23,19 @@ pub(crate) fn run_cli(
     source_filter: Option<&str>,
     time_filter: Option<&str>,
 ) -> Result<()> {
+    let time_range = parse_time_range(time_filter)?;
     let sources = usage_source_labels();
 
     if !json {
         let usage_source_filter = resolve_source_filter(source_filter, &sources)?;
-        let usage_time_filter = time_filter.map(|_| parse_time_range(time_filter));
+        let usage_time_filter = time_filter.map(|_| time_range);
         return crate::tui::runner::run(Some((usage_source_filter, usage_time_filter)));
     }
 
     run_usage_sync_job()?;
     let store = Store::open()?;
-    let filters = UsageFilters {
-        sources: resolve_source_filter(source_filter, &sources)?,
-        time_range: parse_time_range(time_filter),
-    };
+    let filters =
+        UsageFilters { sources: resolve_source_filter(source_filter, &sources)?, time_range };
     let report = build_usage_report(&store, &filters)?;
 
     println!("{}", serde_json::to_string_pretty(&report)?);