diff --git a/Cargo.lock b/Cargo.lock
index d8d82d285..c8bf13bff 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1469,5 +1469,6 @@ dependencies = [
  "helix-core",
  "helix-loader",
  "helix-term",
+ "helix-view",
  "toml",
 ]
diff --git a/book/src/themes.md b/book/src/themes.md
index b37ee8524..9908456fc 100644
--- a/book/src/themes.md
+++ b/book/src/themes.md
@@ -254,4 +254,10 @@ #### Interface
 | `diagnostic.warning`      | Diagnostics warning (editing area)             |
 | `diagnostic.error`        | Diagnostics error (editing area)               |
 
+You can check compliance to spec with
+
+```shell
+cargo xtask themelint onedark  # replace onedark with <name>
+```
+
 [editor-section]: ./configuration.md#editor-section
diff --git a/xtask/Cargo.toml b/xtask/Cargo.toml
index 76c38c99e..127b931cf 100644
--- a/xtask/Cargo.toml
+++ b/xtask/Cargo.toml
@@ -8,5 +8,6 @@ edition = "2021"
 [dependencies]
 helix-term = { version = "0.6", path = "../helix-term" }
 helix-core = { version = "0.6", path = "../helix-core" }
+helix-view = { version = "0.6", path = "../helix-view" }
 helix-loader = { version = "0.6", path = "../helix-loader" }
 toml = "0.5"
diff --git a/xtask/src/docgen.rs b/xtask/src/docgen.rs
new file mode 100644
index 000000000..473882f3e
--- /dev/null
+++ b/xtask/src/docgen.rs
@@ -0,0 +1,117 @@
+use crate::helpers;
+use crate::path;
+use crate::DynError;
+
+use helix_term::commands::TYPABLE_COMMAND_LIST;
+use helix_term::health::TsFeature;
+use std::fs;
+
+pub const TYPABLE_COMMANDS_MD_OUTPUT: &str = "typable-cmd.md";
+pub const LANG_SUPPORT_MD_OUTPUT: &str = "lang-support.md";
+
+fn md_table_heading(cols: &[String]) -> String {
+    let mut header = String::new();
+    header += &md_table_row(cols);
+    header += &md_table_row(&vec!["---".to_string(); cols.len()]);
+    header
+}
+
+fn md_table_row(cols: &[String]) -> String {
+    format!("| {} |\n", cols.join(" | "))
+}
+
+fn md_mono(s: &str) -> String {
+    format!("`{}`", s)
+}
+
+pub fn typable_commands() -> Result<String, DynError> {
+    let mut md = String::new();
+    md.push_str(&md_table_heading(&[
+        "Name".to_owned(),
+        "Description".to_owned(),
+    ]));
+
+    let cmdify = |s: &str| format!("`:{}`", s);
+
+    for cmd in TYPABLE_COMMAND_LIST {
+        let names = std::iter::once(&cmd.name)
+            .chain(cmd.aliases.iter())
+            .map(|a| cmdify(a))
+            .collect::<Vec<_>>()
+            .join(", ");
+
+        let doc = cmd.doc.replace('\n', "<br>");
+
+        md.push_str(&md_table_row(&[names.to_owned(), doc.to_owned()]));
+    }
+
+    Ok(md)
+}
+
+pub fn lang_features() -> Result<String, DynError> {
+    let mut md = String::new();
+    let ts_features = TsFeature::all();
+
+    let mut cols = vec!["Language".to_owned()];
+    cols.append(
+        &mut ts_features
+            .iter()
+            .map(|t| t.long_title().to_string())
+            .collect::<Vec<_>>(),
+    );
+    cols.push("Default LSP".to_owned());
+
+    md.push_str(&md_table_heading(&cols));
+    let config = helpers::lang_config();
+
+    let mut langs = config
+        .language
+        .iter()
+        .map(|l| l.language_id.clone())
+        .collect::<Vec<_>>();
+    langs.sort_unstable();
+
+    let mut ts_features_to_langs = Vec::new();
+    for &feat in ts_features {
+        ts_features_to_langs.push((feat, helpers::ts_lang_support(feat)));
+    }
+
+    let mut row = Vec::new();
+    for lang in langs {
+        let lc = config
+            .language
+            .iter()
+            .find(|l| l.language_id == lang)
+            .unwrap(); // lang comes from config
+        row.push(lc.language_id.clone());
+
+        for (_feat, support_list) in &ts_features_to_langs {
+            row.push(
+                if support_list.contains(&lang) {
+                    "✓"
+                } else {
+                    ""
+                }
+                .to_owned(),
+            );
+        }
+        row.push(
+            lc.language_server
+                .as_ref()
+                .map(|s| s.command.clone())
+                .map(|c| md_mono(&c))
+                .unwrap_or_default(),
+        );
+
+        md.push_str(&md_table_row(&row));
+        row.clear();
+    }
+
+    Ok(md)
+}
+
+pub fn write(filename: &str, data: &str) {
+    let error = format!("Could not write to {}", filename);
+    let path = path::book_gen().join(filename);
+    fs::write(path, data).expect(&error);
+}
diff --git a/xtask/src/helpers.rs b/xtask/src/helpers.rs
new file mode 100644
index 000000000..4f759e74f
--- /dev/null
+++ b/xtask/src/helpers.rs
@@ -0,0 +1,44 @@
+use std::path::{Path, PathBuf};
+
+use crate::path;
+use helix_core::syntax::Configuration as LangConfig;
+use helix_term::health::TsFeature;
+
+/// Get the list of languages that support a particular tree-sitter
+/// based feature.
+pub fn ts_lang_support(feat: TsFeature) -> Vec<String> {
+    let queries_dir = path::ts_queries();
+
+    find_files(&queries_dir, feat.runtime_filename())
+        .iter()
+        .map(|f| {
+            // .../helix/runtime/queries/python/highlights.scm
+            let tail = f.strip_prefix(&queries_dir).unwrap(); // python/highlights.scm
+            let lang = tail.components().next().unwrap(); // python
+            lang.as_os_str().to_string_lossy().to_string()
+        })
+        .collect()
+}
+
+// naive implementation, but suffices for our needs
+pub fn find_files(dir: &Path, filename: &str) -> Vec<PathBuf> {
+    std::fs::read_dir(dir)
+        .unwrap()
+        .filter_map(|entry| {
+            let path = entry.ok()?.path();
+            if path.is_dir() {
+                Some(find_files(&path, filename))
+            } else if path.file_name()?.to_string_lossy() == filename {
+                Some(vec![path])
+            } else {
+                None
+            }
+        })
+        .flatten()
+        .collect()
+}
+
+pub fn lang_config() -> LangConfig {
+    let bytes = std::fs::read(path::lang_config()).unwrap();
+    toml::from_slice(&bytes).unwrap()
+}
diff --git a/xtask/src/main.rs b/xtask/src/main.rs
index c7640cd1e..1421fd1a1 100644
--- a/xtask/src/main.rs
+++ b/xtask/src/main.rs
@@ -1,255 +1,35 @@
+mod docgen;
+mod helpers;
+mod path;
+mod querycheck;
+mod themelint;
+
 use std::{env, error::Error};
 
 type DynError = Box<dyn Error>;
 
-pub mod helpers {
-    use std::path::{Path, PathBuf};
-
-    use crate::path;
-    use helix_core::syntax::Configuration as LangConfig;
-    use helix_term::health::TsFeature;
-
-    /// Get the list of languages that support a particular tree-sitter
-    /// based feature.
-    pub fn ts_lang_support(feat: TsFeature) -> Vec<String> {
-        let queries_dir = path::ts_queries();
-
-        find_files(&queries_dir, feat.runtime_filename())
-            .iter()
-            .map(|f| {
-                // .../helix/runtime/queries/python/highlights.scm
-                let tail = f.strip_prefix(&queries_dir).unwrap(); // python/highlights.scm
-                let lang = tail.components().next().unwrap(); // python
-                lang.as_os_str().to_string_lossy().to_string()
-            })
-            .collect()
-    }
-
-    /// Get the list of languages that have any form of tree-sitter
-    /// queries defined in the runtime directory.
-    pub fn langs_with_ts_queries() -> Vec<String> {
-        std::fs::read_dir(path::ts_queries())
-            .unwrap()
-            .filter_map(|entry| {
-                let entry = entry.ok()?;
-                entry
-                    .file_type()
-                    .ok()?
-                    .is_dir()
-                    .then(|| entry.file_name().to_string_lossy().to_string())
-            })
-            .collect()
-    }
-
-    // naive implementation, but suffices for our needs
-    pub fn find_files(dir: &Path, filename: &str) -> Vec<PathBuf> {
-        std::fs::read_dir(dir)
-            .unwrap()
-            .filter_map(|entry| {
-                let path = entry.ok()?.path();
-                if path.is_dir() {
-                    Some(find_files(&path, filename))
-                } else {
-                    (path.file_name()?.to_string_lossy() == filename).then(|| vec![path])
-                }
-            })
-            .flatten()
-            .collect()
-    }
-
-    pub fn lang_config() -> LangConfig {
-        let bytes = std::fs::read(path::lang_config()).unwrap();
-        toml::from_slice(&bytes).unwrap()
-    }
-}
-
-pub mod md_gen {
-    use crate::DynError;
-
-    use crate::helpers;
-    use crate::path;
-    use helix_term::commands::TYPABLE_COMMAND_LIST;
-    use helix_term::health::TsFeature;
-    use std::fs;
-
-    pub const TYPABLE_COMMANDS_MD_OUTPUT: &str = "typable-cmd.md";
-    pub const LANG_SUPPORT_MD_OUTPUT: &str = "lang-support.md";
-
-    fn md_table_heading(cols: &[String]) -> String {
-        let mut header = String::new();
-        header += &md_table_row(cols);
-        header += &md_table_row(&vec!["---".to_string(); cols.len()]);
-        header
-    }
-
-    fn md_table_row(cols: &[String]) -> String {
-        format!("| {} |\n", cols.join(" | "))
-    }
-
-    fn md_mono(s: &str) -> String {
-        format!("`{}`", s)
-    }
-
-    pub fn typable_commands() -> Result<String, DynError> {
-        let mut md = String::new();
-        md.push_str(&md_table_heading(&[
-            "Name".to_owned(),
-            "Description".to_owned(),
-        ]));
-
-        let cmdify = |s: &str| format!("`:{}`", s);
-
-        for cmd in TYPABLE_COMMAND_LIST {
-            let names = std::iter::once(&cmd.name)
-                .chain(cmd.aliases.iter())
-                .map(|a| cmdify(a))
-                .collect::<Vec<_>>()
-                .join(", ");
-
-            let doc = cmd.doc.replace('\n', "<br>");
-
-            md.push_str(&md_table_row(&[names.to_owned(), doc.to_owned()]));
-        }
-
-        Ok(md)
-    }
-
-    pub fn lang_features() -> Result<String, DynError> {
-        let mut md = String::new();
-        let ts_features = TsFeature::all();
-
-        let mut cols = vec!["Language".to_owned()];
-        cols.append(
-            &mut ts_features
-                .iter()
-                .map(|t| t.long_title().to_string())
-                .collect::<Vec<_>>(),
-        );
-        cols.push("Default LSP".to_owned());
-
-        md.push_str(&md_table_heading(&cols));
-        let config = helpers::lang_config();
-
-        let mut langs = config
-            .language
-            .iter()
-            .map(|l| l.language_id.clone())
-            .collect::<Vec<_>>();
-        langs.sort_unstable();
-
-        let mut ts_features_to_langs = Vec::new();
-        for &feat in ts_features {
-            ts_features_to_langs.push((feat, helpers::ts_lang_support(feat)));
-        }
-
-        let mut row = Vec::new();
-        for lang in langs {
-            let lc = config
-                .language
-                .iter()
-                .find(|l| l.language_id == lang)
-                .unwrap(); // lang comes from config
-            row.push(lc.language_id.clone());
-
-            for (_feat, support_list) in &ts_features_to_langs {
-                row.push(
-                    if support_list.contains(&lang) {
-                        "✓"
-                    } else {
-                        ""
-                    }
-                    .to_owned(),
-                );
-            }
-            row.push(
-                lc.language_server
-                    .as_ref()
-                    .map(|s| s.command.clone())
-                    .map(|c| md_mono(&c))
-                    .unwrap_or_default(),
-            );
-
-            md.push_str(&md_table_row(&row));
-            row.clear();
-        }
-
-        Ok(md)
-    }
-
-    pub fn write(filename: &str, data: &str) {
-        let error = format!("Could not write to {}", filename);
-        let path = path::book_gen().join(filename);
-        fs::write(path, data).expect(&error);
-    }
-}
-
-pub mod path {
-    use std::path::{Path, PathBuf};
-
-    pub fn project_root() -> PathBuf {
-        Path::new(env!("CARGO_MANIFEST_DIR"))
-            .parent()
-            .unwrap()
-            .to_path_buf()
-    }
-
-    pub fn book_gen() -> PathBuf {
-        project_root().join("book/src/generated/")
-    }
-
-    pub fn ts_queries() -> PathBuf {
-        project_root().join("runtime/queries")
-    }
-
-    pub fn lang_config() -> PathBuf {
-        project_root().join("languages.toml")
-    }
-}
-
 pub mod tasks {
-    use crate::md_gen;
+    use crate::docgen::{lang_features, typable_commands, write};
+    use crate::docgen::{LANG_SUPPORT_MD_OUTPUT, TYPABLE_COMMANDS_MD_OUTPUT};
+    use crate::querycheck::query_check;
+    use crate::themelint::{lint, lint_all};
     use crate::DynError;
 
     pub fn docgen() -> Result<(), DynError> {
-        use md_gen::*;
         write(TYPABLE_COMMANDS_MD_OUTPUT, &typable_commands()?);
         write(LANG_SUPPORT_MD_OUTPUT, &lang_features()?);
         Ok(())
     }
 
-    pub fn query_check() -> Result<(), String> {
-        use crate::helpers::lang_config;
-        use helix_core::{syntax::read_query, tree_sitter::Query};
-        use helix_loader::grammar::get_language;
-
-        let query_files = [
-            "highlights.scm",
-            "locals.scm",
-            "injections.scm",
-            "textobjects.scm",
-            "indents.scm",
-        ];
-
-        for language in lang_config().language {
-            let language_name = language.language_id.to_ascii_lowercase();
-            let grammar_name = language.grammar.unwrap_or(language.language_id);
-            for query_file in query_files {
-                let language = get_language(&grammar_name);
-                let query_text = read_query(&language_name, query_file);
-                if !query_text.is_empty() && language.is_ok() {
-                    if let Err(reason) = Query::new(language.unwrap(), &query_text) {
-                        return Err(format!(
-                            "Failed to parse {} queries for {}: {}",
-                            query_file, language_name, reason
-                        ));
-                    }
-                }
-            }
+    pub fn themelint(file: Option<String>) -> Result<(), DynError> {
+        match file {
+            Some(file) => lint(file),
+            None => lint_all(),
         }
+    }
 
-        println!("Query check succeeded");
-
-        Ok(())
+    pub fn querycheck() -> Result<(), DynError> {
+        query_check()
     }
 
     pub fn print_help() {
@@ -259,6 +39,7 @@ pub fn print_help() {
 
     Tasks:
         docgen: Generate files to be included in the mdbook output.
+        themelint <theme>: Report errors for <theme>, or all themes if no theme is specified.
         query-check: Check that tree-sitter queries are valid.
 "
         );
@@ -271,7 +52,8 @@ fn main() -> Result<(), DynError> {
         None => tasks::print_help(),
         Some(t) => match t.as_str() {
             "docgen" => tasks::docgen()?,
-            "query-check" => tasks::query_check()?,
+            "themelint" => tasks::themelint(env::args().nth(2))?,
+            "query-check" => tasks::querycheck()?,
             invalid => return Err(format!("Invalid task name: {}", invalid).into()),
         },
     };
diff --git a/xtask/src/path.rs b/xtask/src/path.rs
new file mode 100644
index 000000000..6f4545c27
--- /dev/null
+++ b/xtask/src/path.rs
@@ -0,0 +1,24 @@
+use std::path::{Path, PathBuf};
+
+pub fn project_root() -> PathBuf {
+    Path::new(env!("CARGO_MANIFEST_DIR"))
+        .parent()
+        .unwrap()
+        .to_path_buf()
+}
+
+pub fn book_gen() -> PathBuf {
+    project_root().join("book/src/generated/")
+}
+
+pub fn ts_queries() -> PathBuf {
+    project_root().join("runtime/queries")
+}
+
+pub fn lang_config() -> PathBuf {
+    project_root().join("languages.toml")
+}
+
+pub fn themes() -> PathBuf {
+    project_root().join("runtime/themes")
+}
diff --git a/xtask/src/querycheck.rs b/xtask/src/querycheck.rs
new file mode 100644
index 000000000..5595b8ec8
--- /dev/null
+++ b/xtask/src/querycheck.rs
@@ -0,0 +1,39 @@
+use crate::DynError;
+
+pub fn query_check() -> Result<(), DynError> {
+    use crate::helpers::lang_config;
+    use helix_core::{syntax::read_query, tree_sitter::Query};
+    use helix_loader::grammar::get_language;
+
+    let query_files = [
+        "highlights.scm",
+        "locals.scm",
+        "injections.scm",
+        "textobjects.scm",
+        "indents.scm",
+    ];
+
+    for language in lang_config().language {
+        let language_name = language.language_id.to_ascii_lowercase();
+        let grammar_name = language.grammar.unwrap_or(language.language_id);
+        for query_file in query_files {
+            let language = get_language(&grammar_name);
+            let query_text = read_query(&language_name, query_file);
+            if let Ok(lang) = language {
+                if !query_text.is_empty() {
+                    if let Err(reason) = Query::new(lang, &query_text) {
+                        return Err(format!(
+                            "Failed to parse {} queries for {}: {}",
+                            query_file, language_name, reason
+                        )
+                        .into());
+                    }
+                }
+            }
+        }
+    }
+
+    println!("Query check succeeded");
+
+    Ok(())
+}
diff --git a/xtask/src/themelint.rs b/xtask/src/themelint.rs
new file mode 100644
index 000000000..26d1cb04e
--- /dev/null
+++ b/xtask/src/themelint.rs
@@ -0,0 +1,199 @@
+use crate::path;
+use crate::DynError;
+use helix_view::theme::Loader;
+use helix_view::theme::Modifier;
+use helix_view::Theme;
+
+struct Rule {
+    fg: Option<&'static str>,
+    bg: Option<&'static str>,
+    check_both: bool,
+}
+
+enum Require {
+    Existence(Rule),
+    Difference(&'static str, &'static str),
+}
+
+// Placed in an fn here, so it's the first thing you see
+fn get_rules() -> Vec<Require> {
+    vec![
+        // Check for ui.selection, which is required
+        Require::Existence(Rule::has_either("ui.selection")),
+        Require::Existence(Rule::has_either("ui.selection.primary")),
+        Require::Difference("ui.selection", "ui.selection.primary"),
+        // Check for planned readable text
+        Require::Existence(Rule::has_fg("ui.text")),
+        Require::Existence(Rule::has_bg("ui.background")),
+        // Check for complete editor.statusline bare minimum
+        Require::Existence(Rule::has_both("ui.statusline")),
+        Require::Existence(Rule::has_both("ui.statusline.inactive")),
+        // Check for editor.color-modes
+        Require::Existence(Rule::has_either("ui.statusline.normal")),
+        Require::Existence(Rule::has_either("ui.statusline.insert")),
+        Require::Existence(Rule::has_either("ui.statusline.select")),
+        Require::Difference("ui.statusline.normal", "ui.statusline.insert"),
+        Require::Difference("ui.statusline.normal", "ui.statusline.select"),
+        // Check for editor.cursorline
+        Require::Existence(Rule::has_bg("ui.cursorline.primary")),
+        // Check for editor.whitespace
+        Require::Existence(Rule::has_fg("ui.virtual.whitespace")),
+        // Check fir rulers
+        Require::Existence(Rule::has_either("ui.virtual.indent-guide")),
+        // Check for editor.rulers
+        Require::Existence(Rule::has_either("ui.virtual.ruler")),
+        // Check for menus and prompts
+        Require::Existence(Rule::has_both("ui.menu")),
+        Require::Existence(Rule::has_both("ui.help")),
+        Require::Existence(Rule::has_bg("ui.popup")),
+        Require::Existence(Rule::has_either("ui.window")),
+        // Check for visible cursor
+        Require::Existence(Rule::has_bg("ui.cursor.primary")),
+        Require::Existence(Rule::has_either("ui.cursor.match")),
+    ]
+}
+
+impl Rule {
+    fn has_bg(bg: &'static str) -> Rule {
+        Rule {
+            fg: None,
+            bg: Some(bg),
+            check_both: true,
+        }
+    }
+    fn has_fg(fg: &'static str) -> Rule {
+        Rule {
+            fg: Some(fg),
+            bg: None,
+            check_both: true,
+        }
+    }
+    fn has_either(item: &'static str) -> Rule {
+        Rule {
+            fg: Some(item),
+            bg: Some(item),
+            check_both: false,
+        }
+    }
+    fn has_both(item: &'static str) -> Rule {
+        Rule {
+            fg: Some(item),
+            bg: Some(item),
+            check_both: true,
+        }
+    }
+    fn found_fg(&self, theme: &Theme) -> bool {
+        if let Some(fg) = &self.fg {
+            if theme.get(fg).fg.is_none() && theme.get(fg).add_modifier == Modifier::empty() {
+                return false;
+            }
+        }
+        true
+    }
+    fn found_bg(&self, theme: &Theme) -> bool {
+        if let Some(bg) = &self.bg {
+            if theme.get(bg).bg.is_none() && theme.get(bg).add_modifier == Modifier::empty() {
+                return false;
+            }
+        }
+        true
+    }
+    fn rule_name(&self) -> &'static str {
+        if self.fg.is_some() {
+            self.fg.unwrap()
+        } else if self.bg.is_some() {
+            self.bg.unwrap()
+        } else {
+            "LINTER_ERROR_NO_RULE"
+        }
+    }
+
+    fn check_difference(
+        theme: &Theme,
+        a: &'static str,
+        b: &'static str,
+        messages: &mut Vec<String>,
+    ) {
+        let theme_a = theme.get(a);
+        let theme_b = theme.get(b);
+        if theme_a == theme_b {
+            messages.push(format!("$THEME: `{}` and `{}` cannot be equal", a, b));
+        }
+    }
+
+    fn check_existence(rule: &Rule, theme: &Theme, messages: &mut Vec<String>) {
+        let found_fg = rule.found_fg(theme);
+        let found_bg = rule.found_bg(theme);
+
+        if !rule.check_both && (found_fg || found_bg) {
+            return;
+        }
+        if !found_fg || !found_bg {
+            let mut missing = vec![];
+            if !found_fg {
+                missing.push("`fg`");
+            }
+            if !found_bg {
+                missing.push("`bg`");
+            }
+            let entry = if !rule.check_both && !found_fg && !found_bg {
+                missing.join(" or ")
+            } else {
+                missing.join(" and ")
+            };
+            messages.push(format!(
+                "$THEME: missing {} for `{}`",
+                entry,
+                rule.rule_name()
+            ))
+        }
+    }
+}
+
+pub fn lint(file: String) -> Result<(), DynError> {
+    if file.contains("base16") {
+        println!("Skipping base16: {}", file);
+        return Ok(());
+    }
+    let path = path::themes().join(file.clone() + ".toml");
+    let theme = std::fs::read(&path).unwrap();
+    let theme: Theme = toml::from_slice(&theme).expect("Failed to parse theme");
+
+    let mut messages: Vec<String> = vec![];
+    get_rules().iter().for_each(|lint| match lint {
+        Require::Existence(rule) => Rule::check_existence(rule, &theme, &mut messages),
+        Require::Difference(a, b) => Rule::check_difference(&theme, a, b, &mut messages),
+    });
+
+    if !messages.is_empty() {
+        messages.iter().for_each(|m| {
+            let theme = file.clone();
+            let message = m.replace("$THEME", theme.as_str());
+            println!("{}", message);
+        });
+        Err(format!("{} has issues", file.clone().as_str()).into())
+    } else {
+        Ok(())
+    }
+}
+
+pub fn lint_all() -> Result<(), DynError> {
+    let files = Loader::read_names(path::themes().as_path());
+    let files_count = files.len();
+    let ok_files_count = files
+        .into_iter()
+        .filter_map(|path| lint(path.replace(".toml", "")).ok())
+        .collect::<Vec<()>>()
+        .len();
+
+    if files_count != ok_files_count {
+        Err(format!(
+            "{} of {} themes had issues",
+            files_count - ok_files_count,
+            files_count
+        )
+        .into())
+    } else {
+        Ok(())
+    }
+}