diff --git a/hubs/cli-check.md b/hubs/cli-check.md
index 589f944..25c4a9c 100644
--- a/hubs/cli-check.md
+++ b/hubs/cli-check.md
@@ -19,7 +19,7 @@ anchors:
       divergence (blocking the run) rather than being silently skipped, so a frontmatter typo
       can't pass as clean.
     at: surf-cli/src/check.rs > check_workspace
-    hash: c29434a58059
+    hash: df30746fb6b2
 refs: []
 ---
 
diff --git a/hubs/cli-for.md b/hubs/cli-for.md
index 5f209e1..cf8b8b5 100644
--- a/hubs/cli-for.md
+++ b/hubs/cli-for.md
@@ -2,11 +2,14 @@
 summary: surf for — reverse lookup of hubs/claims anchored into a file; read-only query.
 anchors:
   - claim: >
-      run normalizes the queried path to workspace-root-relative form, finds the matching claims,
-      and prints them grouped by hub (human) or as a versioned {version, path, matches} envelope
-      (JSON). It is a query, not a gate, so it always exits 0 whether or not anything matched.
+      run normalizes the queried path to workspace-root-relative form, then verifies it is a
+      regular file on disk — a nonexistent/mistyped path, a directory, or a trailing slash errors
+      (exit 1) rather than reporting "no hubs anchor", so a typo can't read as safe-to-edit. For a
+      real file it finds the matching claims and prints them grouped by hub (human) or as a
+      versioned {version, path, matches} envelope (JSON), always exiting 0 whether or not anything
+      matched.
     at: surf-cli/src/for_path.rs > run
-    hash: 0e15525b1340
+    hash: 3ffb208cc1db
   - claim: >
       find collects every claim whose anchored file equals the queried path (matched on path only —
       no source parse), optionally narrowed to anchors whose first segment is the given symbol.
diff --git a/hubs/cli-stats.md b/hubs/cli-stats.md
index 728115a..3dc9f78 100644
--- a/hubs/cli-stats.md
+++ b/hubs/cli-stats.md
@@ -13,9 +13,10 @@ anchors:
       rubber-stamp numerator only when the claim's prose was unchanged. A claim-touch event is a
       commit that changed a file the claim anchors; it counts toward the in-place numerator when
       the claim's stored hash was updated in that same commit. Claim identity is its at: site(s),
-      and missing git history is a hard error rather than a silent zero.
+      and missing git history or an invalid hub glob in surf.toml is a hard error rather than a
+      silent zero or a quietly-narrowed hub set.
     at: surf-cli/src/stats.rs > compute
-    hash: 55561222d721
+    hash: c58b950866ba
 refs: ["../docs/guides/stats.md"]
 ---
 
diff --git a/surf-cli/src/check.rs b/surf-cli/src/check.rs
index 7c836a4..478ae28 100644
--- a/surf-cli/src/check.rs
+++ b/surf-cli/src/check.rs
@@ -42,7 +42,7 @@ fn check_workspace(
     base: Option<&str>,
     files: &[String],
 ) -> Result<Vec<Divergence>> {
-    let scope = Scope::build(ws, base, files);
+    let scope = Scope::build(ws, base, files)?;
     // Enrichment always needs a ref; an explicit --base doubles as the diff base, else HEAD.
     let enrich_base = base.unwrap_or("HEAD");
 
@@ -93,15 +93,20 @@ struct Scope {
 }
 
 impl Scope {
-    fn build(ws: &Workspace, base: Option<&str>, files: &[String]) -> Scope {
+    fn build(ws: &Workspace, base: Option<&str>, files: &[String]) -> Result<Scope> {
         // A bad ref / non-repo yields None — we fall back to a full check rather than
         // silently checking nothing.
         let changed = base.and_then(|b| git::changed_files(&ws.root, b));
+        // Invalid glob *syntax* must fail loudly: silently dropping a `--files` pattern
+        // changes the gate's scope with no signal (#38). Zero *matches* stay fine.
         let globs = files
             .iter()
-            .filter_map(|p| glob::Pattern::new(p).ok())
-            .collect();
-        Scope { changed, globs }
+            .map(|p| {
+                glob::Pattern::new(p)
+                    .map_err(|e| anyhow::anyhow!("invalid --files glob \"{p}\": {e}"))
+            })
+            .collect::<Result<Vec<_>>>()?;
+        Ok(Scope { changed, globs })
     }
 
     fn includes(&self, claim: &surf_core::Claim) -> bool {
@@ -328,6 +333,17 @@ mod tests {
             .is_empty());
     }
 
+    #[test]
+    fn invalid_files_glob_syntax_errors() {
+        // A malformed `--files` pattern must fail loudly, not silently widen/narrow scope (#38).
+        let tmp = tempfile::tempdir().unwrap();
+        let root = tmp.path();
+        write(root, "surf.toml", "");
+        let err = check_workspace(&ws_at(root.to_path_buf()), None, &["src/[".to_string()])
+            .unwrap_err();
+        assert!(err.to_string().contains("src/["), "got: {err}");
+    }
+
     #[test]
     fn per_symbol_not_per_file() {
         // Anchor `add`; modify the *other* function in the same file. Must stay clean.
diff --git a/surf-cli/src/for_path.rs b/surf-cli/src/for_path.rs
index f1a509a..7023f46 100644
--- a/surf-cli/src/for_path.rs
+++ b/surf-cli/src/for_path.rs
@@ -1,11 +1,13 @@
 //! `surf for <path> [symbol]` — reverse lookup: which hubs/claims anchor into a file (#31).
 //! The inverse of authoring — pull up the claims governing a file before you edit it. Reuses the
 //! hub/anchor machinery and only matches on the anchored *path*, so it stays deterministic with
-//! no model, network, or source parse. A query, not a gate: it always exits 0.
+//! no model, network, or source parse. A query, not a gate: for an existing file it always exits
+//! 0 (matched or not), but a path that isn't a regular file errors (exit 1) so a typo can't read
+//! as "nothing anchors here, safe to edit" (#53).
 
 use crate::format::Format;
 use crate::workspace::Workspace;
-use anyhow::Result;
+use anyhow::{bail, Result};
 use serde::Serialize;
 use std::process::ExitCode;
 use surf_core::{parse_anchor, REPORT_VERSION};
@@ -25,7 +27,15 @@ struct ForReport {
 }
 
 pub fn run(ws: &Workspace, path: &str, symbol: Option<&str>, format: Format) -> Result<ExitCode> {
+    // A pre-edit safety check that can't tell "no claims" from "wrong path" is worse than
+    // useless — it greenlights editing a file that isn't the one you meant. Stat first, like
+    // `suggest` does for its globs (#30, #53). Resolve against the root so a root-relative
+    // query is checked where anchors actually live, not against the cwd.
     let query = normalize(ws, path);
+    if !ws.root.join(&query).is_file() {
+        bail!("no such file: {path} (path does not exist or is not a regular file)");
+    }
+
     let matches = find(ws, &query, symbol)?;
 
     match format {
@@ -162,6 +172,26 @@ mod tests {
         assert_eq!(normalize(&ws, abs.to_str().unwrap()), "src/x.rs");
     }
 
+    #[test]
+    fn run_errors_on_nonexistent_path() {
+        // A typo must not look like "nothing anchors here, safe to edit".
+        let (_t, ws) = ws_with(&[("hubs/a.md", HUB)]);
+        assert!(run(&ws, "src/x.rs", None, Format::Human).is_err());
+    }
+
+    #[test]
+    fn run_errors_on_directory() {
+        let (_t, ws) = ws_with(&[("hubs/a.md", HUB), ("src/x.rs", "fn foo() {}\n")]);
+        assert!(run(&ws, "src", None, Format::Human).is_err());
+    }
+
+    #[test]
+    fn run_succeeds_on_real_file_even_when_unanchored() {
+        // Genuinely-existing-but-unanchored keeps exit 0; only the wrong-path case errors.
+        let (_t, ws) = ws_with(&[("hubs/a.md", HUB), ("src/lonely.rs", "fn solo() {}\n")]);
+        assert!(run(&ws, "src/lonely.rs", None, Format::Human).is_ok());
+    }
+
     #[test]
     fn json_envelope_is_versioned() {
         let (_t, ws) = ws_with(&[("hubs/a.md", HUB)]);
diff --git a/surf-cli/src/stats.rs b/surf-cli/src/stats.rs
index b975bb1..170533b 100644
--- a/surf-cli/src/stats.rs
+++ b/surf-cli/src/stats.rs
@@ -77,12 +77,17 @@ pub fn run(
 }
 
 fn compute(ws: &Workspace, since: Option<&str>, until: Option<&str>) -> Result<StatsReport> {
+    // A bad hub glob in surf.toml must fail loudly: silently dropping it excludes hubs from the
+    // metrics with no signal (#38). stats already fails loudly when git can't answer; do the same
+    // for malformed config rather than reporting on a quietly-narrowed hub set.
     let patterns: Vec<glob::Pattern> = ws
         .config
         .hubs
         .iter()
-        .filter_map(|p| glob::Pattern::new(p).ok())
-        .collect();
+        .map(|p| {
+            glob::Pattern::new(p).map_err(|e| anyhow!("invalid hub glob \"{p}\" in surf.toml: {e}"))
+        })
+        .collect::<Result<Vec<_>>>()?;
 
     // Unlike check's advisory git, stats *is* a history report: if git can't answer, fail loudly
     // rather than printing a misleading zero.
@@ -244,6 +249,16 @@ mod tests {
         Workspace::discover(root).unwrap()
     }
 
+    #[test]
+    fn invalid_hub_glob_syntax_errors() {
+        // A malformed hub glob in surf.toml must fail loudly, not silently exclude hubs (#38).
+        let tmp = tempfile::tempdir().unwrap();
+        let root = tmp.path();
+        write(root, "surf.toml", "hubs = [\"hubs/[.md\"]\n");
+        let err = compute(&ws(root), None, None).unwrap_err();
+        assert!(err.to_string().contains("hubs/["), "got: {err}");
+    }
+
     #[test]
     fn rubber_stamp_when_hash_changes_but_prose_does_not() {
         let tmp = tempfile::tempdir().unwrap();