fix(config): redirect misplaced nested keys to the other config with a scope note

src/commands/config/show.rs

@@ -766,7 +766,10 @@ fn format_show_warning(warning: &worktrunk::config::UnknownWarning) -> String {
         UnknownWarning::TopLevelWrongConfig {
             key,
             other_description,
-        } => cformat!("Key <bold>{key}</> belongs in {other_description} (will be ignored)"),
+        } => with_scope_note(
+            cformat!("Key <bold>{key}</> belongs in {other_description} (will be ignored)"),
+            other_description,
+        ),
         UnknownWarning::TopLevelDeprecatedWrongConfig {
             key,
             other_description,
@@ -775,13 +778,26 @@ fn format_show_warning(warning: &worktrunk::config::UnknownWarning) -> String {
         UnknownWarning::NestedWrongConfig {
             path,
             other_description,
-        } => cformat!("Key <bold>{path}</> belongs in {other_description} (will be ignored)"),
+        } => with_scope_note(
+            cformat!("Key <bold>{path}</> belongs in {other_description} (will be ignored)"),
+            other_description,
+        ),
         UnknownWarning::NestedUnknown { path } => {
             cformat!("Unknown key <bold>{path}</> will be ignored")
         }
     }
 }
 
+/// Append the project-scoped-user-config note when the key belongs in user
+/// config, mirroring the load-time warning path. See
+/// [`scope_to_repo_note`](worktrunk::config::scope_to_repo_note).
+fn with_scope_note(message: String, other_description: &str) -> String {
+    match worktrunk::config::scope_to_repo_note(other_description) {
+        Some(note) => format!("{message}; {note}"),
+        None => message,
+    }
+}
+
 fn render_project_config(out: &mut String) -> anyhow::Result<()> {
     // Try to get current repository root
     let repo = match Repository::current() {

src/config/deprecation.rs

@@ -1787,6 +1787,19 @@ pub fn nested_key_belongs_in<C: WorktrunkConfig>(path: &str) -> Option<&'static
         .then(C::Other::description)
 }
 
+/// Note appended to a "belongs in user config" warning: a key placed in
+/// project config that really lives in user config is usually an attempt to
+/// scope a personal setting to one repo, which the `[projects."<id>"]` table
+/// in user config does directly. Returns `None` for any other destination.
+///
+/// Keyed off the destination *description* rather than a config-type gate so
+/// both warning formatters (load-time and `config show`) can share it — they
+/// hold only the `other_description` string, not the config type.
+pub fn scope_to_repo_note(other_description: &str) -> Option<&'static str> {
+    (other_description == crate::config::UserConfig::description())
+        .then_some(r#"to scope it to this repo, add it under [projects."<id>"] in user config"#)
+}
+
 /// Classification of an unknown config key for warning purposes.
 pub enum UnknownKeyKind {
     /// Deprecated key in its correct config type — deprecation system handles it
@@ -1871,8 +1884,11 @@ fn format_load_warning(label: &str, warning: &crate::config::UnknownWarning) ->
         UnknownWarning::TopLevelWrongConfig {
             key,
             other_description,
-        } => cformat!(
-            "{label} has key <bold>{key}</> which belongs in {other_description} (will be ignored)"
+        } => with_scope_note(
+            cformat!(
+                "{label} has key <bold>{key}</> which belongs in {other_description} (will be ignored)"
+            ),
+            other_description,
         ),
         UnknownWarning::TopLevelDeprecatedWrongConfig {
             key,
@@ -1884,15 +1900,29 @@ fn format_load_warning(label: &str, warning: &crate::config::UnknownWarning) ->
         UnknownWarning::NestedWrongConfig {
             path,
             other_description,
-        } => cformat!(
-            "{label} has key <bold>{path}</> which belongs in {other_description} (will be ignored)"
+        } => with_scope_note(
+            cformat!(
+                "{label} has key <bold>{path}</> which belongs in {other_description} (will be ignored)"
+            ),
+            other_description,
         ),
         UnknownWarning::NestedUnknown { path } => {
             cformat!("{label} has unknown field <bold>{path}</> (will be ignored)")
         }
     }
 }
 
+/// Append the project-scoped-user-config note to `message` when the key's
+/// destination is user config (see [`scope_to_repo_note`]). Joined with a
+/// semicolon per the house style for related clauses. The note is plain text
+/// so its `[projects."<id>"]` placeholder isn't parsed as color-print markup.
+fn with_scope_note(message: String, other_description: &str) -> String {
+    match scope_to_repo_note(other_description) {
+        Some(note) => format!("{message}; {note}"),
+        None => message,
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -4491,6 +4521,86 @@ ff = true
         );
     }
 
+    #[test]
+    fn test_nested_user_only_key_redirects_generally() {
+        use crate::config::{ProjectConfig, UnknownWarning, UserConfig, collect_unknown_warnings};
+
+        // `[list]` is a valid *shared* section (project config accepts `url`),
+        // but `columns` / `full` are user-config display settings. Placing them
+        // in project config redirects to user config rather than reading
+        // "unknown field" — the general "valid in the other config" check, not
+        // the hard-coded commit.generation list (#3469).
+        let warnings = collect_unknown_warnings::<ProjectConfig>(
+            "[list]\ncolumns = [\"branch\"]\nfull = true\n",
+        );
+        assert!(
+            warnings.iter().all(|w| matches!(
+                w,
+                UnknownWarning::NestedWrongConfig { path, other_description }
+                    if (path == "list.columns" || path == "list.full")
+                        && *other_description == "user config"
+            )) && warnings.len() == 2,
+            "expected list.columns/list.full → user config, got {warnings:?}"
+        );
+
+        // A key unknown in *both* configs stays "unknown field".
+        let warnings = collect_unknown_warnings::<ProjectConfig>("[list]\nnonsense-typo = true\n");
+        assert!(
+            matches!(
+                warnings.as_slice(),
+                [UnknownWarning::NestedUnknown { path }] if path == "list.nonsense-typo"
+            ),
+            "expected list.nonsense-typo → unknown, got {warnings:?}"
+        );
+
+        // The reverse direction: `url` is project-only, so it redirects to
+        // project config when found in user config — no scope-to-repo note
+        // there (that only applies to user-config destinations).
+        let warnings = collect_unknown_warnings::<UserConfig>("[list]\nurl = \"x\"\n");
+        assert!(
+            matches!(
+                warnings.as_slice(),
+                [UnknownWarning::NestedWrongConfig { path, other_description }]
+                    if path == "list.url" && *other_description == "project config"
+            ),
+            "expected list.url → project config, got {warnings:?}"
+        );
+    }
+
+    #[test]
+    fn test_scope_to_repo_note_only_for_user_config() {
+        // The note fires for user-config destinations and nothing else.
+        assert!(scope_to_repo_note("user config").is_some());
+        assert!(scope_to_repo_note("project config").is_none());
+
+        // It reaches the rendered load-warning for a user-config redirect...
+        let note = "to scope it to this repo";
+        let msg = format_load_warning(
+            "Project config",
+            &crate::config::UnknownWarning::NestedWrongConfig {
+                path: "list.columns".to_string(),
+                other_description: "user config",
+            },
+        );
+        assert!(
+            msg.contains(note),
+            "user-config redirect should carry note: {msg}"
+        );
+
+        // ...but not a project-config redirect.
+        let msg = format_load_warning(
+            "User config",
+            &crate::config::UnknownWarning::NestedWrongConfig {
+                path: "list.url".to_string(),
+                other_description: "project config",
+            },
+        );
+        assert!(
+            !msg.contains(note),
+            "project-config redirect should not carry note: {msg}"
+        );
+    }
+
     /// Every `DEPRECATION_RULES` row's migration fires on one config, pinning
     /// cross-rule interactions the per-rule tests can't see — in particular
     /// the inserted `[forge]` staying in the mid-file spot where the user

src/config/mod.rs

@@ -142,7 +142,7 @@ pub use deprecation::suppress_warnings;
 pub use deprecation::warnings_suppressed;
 pub use deprecation::{
     DEPRECATED_SECTION_KEYS, DeprecatedSection, UnknownKeyKind, classify_unknown_key,
-    key_belongs_in, nested_key_belongs_in, warn_unknown_fields,
+    key_belongs_in, nested_key_belongs_in, scope_to_repo_note, warn_unknown_fields,
 };
 pub use deprecation::{DeprecationKind, Deprecations};
 pub use expansion::{

src/config/unknown_tree.rs

@@ -177,6 +177,51 @@ pub enum UnknownWarning {
     NestedUnknown { path: String },
 }
 
+/// Position within `C::Other`'s unknown tree while walking `C`'s nested
+/// unknowns. A nested key that's schema-unknown in `C` but *valid* in
+/// `C::Other` (e.g. `list.columns` — a user-config display setting — placed in
+/// project config) should redirect there rather than read "unknown field". We
+/// answer "is this leaf valid in the other config?" by walking the other
+/// config's unknown tree in lockstep: a key valid there never appears in that
+/// tree, so its absence is the signal.
+#[derive(Clone, Copy)]
+enum OtherStatus<'a> {
+    /// An ancestor section is absent or wholly unknown in `C::Other`, so
+    /// nothing at or below this point is valid there.
+    UnknownSection,
+    /// Within a section that exists in `C::Other`. Carries the corresponding
+    /// node in the other tree, or `None` once no further unknowns are recorded
+    /// — i.e. every key at or below here is valid in the other config.
+    Known(Option<&'a UnknownTree>),
+}
+
+impl<'a> OtherStatus<'a> {
+    /// Whether `key` at the current level is a valid key in `C::Other`.
+    fn key_is_valid_in_other(self, key: &str) -> bool {
+        match self {
+            OtherStatus::UnknownSection => false,
+            OtherStatus::Known(None) => true,
+            OtherStatus::Known(Some(node)) => !node.keys.contains(key),
+        }
+    }
+
+    /// Descend into `key`, returning the status for its children.
+    fn descend(self, key: &str) -> OtherStatus<'a> {
+        match self {
+            OtherStatus::UnknownSection => OtherStatus::UnknownSection,
+            OtherStatus::Known(None) => OtherStatus::Known(None),
+            OtherStatus::Known(Some(node)) => {
+                if node.keys.contains(key) {
+                    // Whole subtree is unknown in the other config too.
+                    OtherStatus::UnknownSection
+                } else {
+                    OtherStatus::Known(node.nested.get(key))
+                }
+            }
+        }
+    }
+}
+
 /// Collect structured warnings for `raw_contents` under config type `C`.
 ///
 /// Top-level classification reads the *raw* tree (so deprecated top-level
@@ -185,6 +230,14 @@ pub enum UnknownWarning {
 /// so patterns the deprecation system already warns about (e.g.,
 /// `switch.no-cd`, `merge.no-ff`) don't double-warn here.
 ///
+/// A misplaced *nested* key is redirected to `C::Other` when it's valid there
+/// — determined by walking `C::Other`'s own unknown tree for the same content
+/// (see the private `OtherStatus` helper). If that other-config analysis is
+/// unreliable, the walk falls back to treating nested keys as unknown, so only
+/// the hard-coded
+/// [`nested_key_belongs_in`](crate::config::nested_key_belongs_in) redirects
+/// still fire.
+///
 /// Returns an empty vec if either analysis is unreliable — the load path
 /// surfaces parse/type errors elsewhere.
 pub fn collect_unknown_warnings<C: WorktrunkConfig>(raw_contents: &str) -> Vec<UnknownWarning> {
@@ -197,6 +250,13 @@ pub fn collect_unknown_warnings<C: WorktrunkConfig>(raw_contents: &str) -> Vec<U
         UnknownAnalysis::Parsed(t) => t,
         UnknownAnalysis::Unreliable(_) => return Vec::new(),
     };
+    // The same content viewed as the *other* config type: a nested key absent
+    // from this tree is valid there. Unreliable → no generalized redirect.
+    let other_analysis = compute_unknown_tree::<C::Other>(&migrated);
+    let other_root = match other_analysis.warn_tree() {
+        Some(t) => OtherStatus::Known(Some(t)),
+        None => OtherStatus::UnknownSection,
+    };
 
     let mut out = Vec::new();
     for key in &raw_tree.keys {
@@ -225,19 +285,25 @@ pub fn collect_unknown_warnings<C: WorktrunkConfig>(raw_contents: &str) -> Vec<U
         if !C::is_valid_key(key) {
             continue; // top-level unknowns were classified above against raw
         }
-        walk_nested::<C>(sub, key, &mut out);
+        walk_nested::<C>(sub, key, other_root.descend(key), &mut out);
     }
     out
 }
 
 fn walk_nested<C: WorktrunkConfig>(
     tree: &UnknownTree,
     prefix: &str,
+    other: OtherStatus,
     out: &mut Vec<UnknownWarning>,
 ) {
     for key in &tree.keys {
         let path = format!("{prefix}.{key}");
-        out.push(match crate::config::nested_key_belongs_in::<C>(&path) {
+        // Hard-coded redirects (commit.generation leaves) take precedence and
+        // fire even when the other-config analysis is unreliable; otherwise
+        // fall back to the general "valid in the other config" check.
+        let belongs = crate::config::nested_key_belongs_in::<C>(&path)
+            .or_else(|| other.key_is_valid_in_other(key).then(C::Other::description));
+        out.push(match belongs {
             Some(other_description) => UnknownWarning::NestedWrongConfig {
                 path,
                 other_description,
@@ -250,7 +316,7 @@ fn walk_nested<C: WorktrunkConfig>(
             continue;
         }
         let path = format!("{prefix}.{key}");
-        walk_nested::<C>(sub, &path, out);
+        walk_nested::<C>(sub, &path, other.descend(key), out);
     }
 }
 

tests/snapshots/integration__integration_tests__config_show__config_show_suggests_user_config_for_commit_generation.snap

@@ -79,7 +79,7 @@ exit_code: 0
   \ No newline at end of file
   +[commit.generation]
   +command = "claude"
-▲ Key commit.generation.command belongs in user config (will be ignored)
+▲ Key commit.generation.command belongs in user config (will be ignored); to scope it to this repo, add it under [projects."<id>"] in user config
 
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