diff --git a/Cargo.lock b/Cargo.lock
index 1972400..6db3a14 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -427,8 +427,10 @@ dependencies = [
  "codebook_config",
  "env_logger",
  "fs2",
+ "glob",
  "log",
  "lru",
+ "owo-colors",
  "serde",
  "serde_json",
  "streaming-iterator",
@@ -436,6 +438,7 @@ dependencies = [
  "tempfile",
  "tokio",
  "tower-lsp",
+ "walkdir",
 ]
 
 [[package]]
@@ -1372,6 +1375,12 @@ dependencies = [
  "windows-sys 0.61.2",
 ]
 
+[[package]]
+name = "is_ci"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7655c9839580ee829dfacba1d1278c2b7883e50a277ff7541299489d6bdfdc45"
+
 [[package]]
 name = "is_terminal_polyfill"
 version = "1.70.2"
@@ -1703,6 +1712,16 @@ version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "04744f49eae99ab78e0d5c0b603ab218f515ea8cfe5a456d7629ad883a3b6e7d"
 
+[[package]]
+name = "owo-colors"
+version = "4.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d211803b9b6b570f68772237e415a029d5a50c65d382910b879fb19d3271f94d"
+dependencies = [
+ "supports-color 2.1.0",
+ "supports-color 3.0.2",
+]
+
 [[package]]
 name = "parking"
 version = "2.2.1"
@@ -2449,6 +2468,25 @@ version = "2.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "13c2bddecc57b384dee18652358fb23172facb8a2c51ccc10d74c157bdea3292"
 
+[[package]]
+name = "supports-color"
+version = "2.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d6398cde53adc3c4557306a96ce67b302968513830a77a95b2b17305d9719a89"
+dependencies = [
+ "is-terminal",
+ "is_ci",
+]
+
+[[package]]
+name = "supports-color"
+version = "3.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c64fc7232dd8d2e4ac5ce4ef302b1d81e0b80d055b9d77c7c4f51f6aa4c867d6"
+dependencies = [
+ "is_ci",
+]
+
 [[package]]
 name = "symbolic-common"
 version = "12.17.2"
diff --git a/Cargo.toml b/Cargo.toml
index 0922004..0ad3137 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -21,6 +21,7 @@ env_logger = "0.11.6"
 fs2 = "0.4"
 git2 = "0.20.0"
 glob = "0.3"
+owo-colors = { version = "4", features = ["supports-colors"] }
 httpmock = "<0.9.0"
 lazy_static = "1.5.0"
 log = "0.4.22"
diff --git a/crates/codebook-lsp/Cargo.toml b/crates/codebook-lsp/Cargo.toml
index a85100b..114e3fd 100644
--- a/crates/codebook-lsp/Cargo.toml
+++ b/crates/codebook-lsp/Cargo.toml
@@ -28,6 +28,9 @@ env_logger.workspace = true
 fs2.workspace = true
 log.workspace = true
 lru.workspace = true
+glob.workspace = true
+owo-colors.workspace = true
+walkdir.workspace = true
 serde.workspace = true
 serde_json.workspace = true
 string-offsets.workspace = true
diff --git a/crates/codebook-lsp/src/lint.rs b/crates/codebook-lsp/src/lint.rs
new file mode 100644
index 0000000..565e4ae
--- /dev/null
+++ b/crates/codebook-lsp/src/lint.rs
@@ -0,0 +1,247 @@
+use codebook::Codebook;
+use codebook_config::CodebookConfigFile;
+use owo_colors::{OwoColorize, Stream, Style};
+use std::collections::HashSet;
+use std::path::{Path, PathBuf};
+use std::sync::Arc;
+
+const BOLD: Style = Style::new().bold();
+const DIM: Style = Style::new().dimmed();
+const YELLOW: Style = Style::new().yellow();
+const BOLD_RED: Style = Style::new().bold().red();
+
+fn fatal(msg: impl std::fmt::Display) -> ! {
+    eprintln!(
+        "{} {msg}",
+        "error:".if_supports_color(Stream::Stderr, |t| t.style(BOLD_RED))
+    );
+    std::process::exit(2);
+}
+
+/// Computes a workspace-relative path string for a given file. Falls back to
+/// the absolute path if the file is outside the workspace or canonicalization fails.
+fn relative_to_root(root: &Path, path: &Path) -> String {
+    let root_canonical = match root.canonicalize() {
+        Ok(r) => r,
+        Err(_) => return path.to_string_lossy().to_string(),
+    };
+    match path.canonicalize() {
+        Ok(canon) => match canon.strip_prefix(&root_canonical) {
+            Ok(rel) => rel.to_string_lossy().to_string(),
+            Err(_) => path.to_string_lossy().to_string(),
+        },
+        Err(_) => path.to_string_lossy().to_string(),
+    }
+}
+
+/// Returns `true` if any spelling errors were found.
+pub fn run_lint(files: &[String], root: &Path, unique: bool, suggest: bool) -> bool {
+    let config = Arc::new(
+        CodebookConfigFile::load(Some(root))
+            .unwrap_or_else(|e| fatal(format!("failed to load config: {e}"))),
+    );
+
+    print_config_source(&config);
+    eprintln!();
+
+    let codebook = Codebook::new(config.clone())
+        .unwrap_or_else(|e| fatal(format!("failed to initialize: {e}")));
+
+    let resolved = resolve_paths(files, root);
+
+    let mut seen_words: HashSet<String> = HashSet::new();
+    let mut total_errors = 0usize;
+    let mut files_with_errors = 0usize;
+
+    for path in &resolved {
+        let relative = relative_to_root(root, path);
+        let error_count = check_file(path, &relative, &codebook, &mut seen_words, unique, suggest);
+        if error_count > 0 {
+            total_errors += error_count;
+            files_with_errors += 1;
+        }
+    }
+
+    let unique_label = if unique { "unique " } else { "" };
+    eprintln!(
+        "Found {} {unique_label}spelling error(s) in {} file(s).",
+        total_errors.if_supports_color(Stream::Stderr, |t| t.style(BOLD)),
+        files_with_errors.if_supports_color(Stream::Stderr, |t| t.style(BOLD)),
+    );
+
+    total_errors > 0
+}
+
+/// Spell-checks a single file and prints any diagnostics to stdout.
+///
+/// Returns the number of errors found (0 if the file was clean or unreadable).
+/// `relative` is the workspace-relative path used for display and ignore matching.
+fn check_file(
+    path: &Path,
+    relative: &str,
+    codebook: &Codebook,
+    seen_words: &mut HashSet<String>,
+    unique: bool,
+    suggest: bool,
+) -> usize {
+    let text = match std::fs::read_to_string(path) {
+        Ok(t) => t,
+        Err(e) => {
+            eprintln!(
+                "{} {}: {e}",
+                "error:".if_supports_color(Stream::Stderr, |t| t.style(BOLD_RED)),
+                path.display()
+            );
+            return 0;
+        }
+    };
+
+    let display = relative.strip_prefix("./").unwrap_or(relative);
+
+    let mut locations = codebook.spell_check(&text, None, Some(relative));
+    // Sort by first occurrence in the file.
+    locations.sort_by_key(|l| l.locations.first().map(|r| r.start_byte).unwrap_or(0));
+
+    // Collect (linecol, word, suggestions) first so we can compute pad_len for alignment.
+    // unique check is per-word (outer loop) so all ranges of a word are included or skipped together.
+    let mut hits: Vec<(String, &str, Option<Vec<String>>)> = Vec::new();
+    for wl in &locations {
+        if unique && !seen_words.insert(wl.word.to_lowercase()) {
+            continue;
+        }
+
+        let suggestions = if suggest {
+            codebook.get_suggestions(wl.word.as_str())
+        } else {
+            None
+        };
+
+        // In unique mode only emit the first occurrence of each word
+        let ranges = if unique {
+            &wl.locations[..1]
+        } else {
+            &wl.locations[..]
+        };
+
+        for range in ranges {
+            let before = &text[..range.start_byte.min(text.len())];
+            let line = before.bytes().filter(|&b| b == b'\n').count() + 1;
+            let col = before
+                .rfind('\n')
+                .map(|p| before.len() - p)
+                .unwrap_or(before.len() + 1);
+            hits.push((
+                format!("{line}:{col}"),
+                wl.word.as_str(),
+                suggestions.clone(),
+            ));
+        }
+    }
+
+    if hits.is_empty() {
+        return 0;
+    }
+
+    let pad_len = hits
+        .iter()
+        .map(|(linecol, _, _)| linecol.len())
+        .max()
+        .unwrap_or(0);
+
+    println!(
+        "{}",
+        display.if_supports_color(Stream::Stdout, |t| t.style(BOLD))
+    );
+    for (linecol, word, suggestions) in &hits {
+        let pad = " ".repeat(pad_len - linecol.len());
+        print!(
+            "  {}:{}{}  {}",
+            display.if_supports_color(Stream::Stdout, |t| t.style(DIM)),
+            linecol.if_supports_color(Stream::Stdout, |t| t.style(YELLOW)),
+            pad,
+            word.if_supports_color(Stream::Stdout, |t| t.style(BOLD_RED)),
+        );
+        if let Some(suggestions) = suggestions {
+            println!(
+                "  {}",
+                format!("→ {}", suggestions.join(", "))
+                    .if_supports_color(Stream::Stdout, |t| t.style(DIM)),
+            );
+        } else {
+            println!();
+        }
+    }
+    println!();
+
+    hits.len()
+}
+
+/// Prints which config file is being used, or notes that the default is active.
+fn print_config_source(config: &CodebookConfigFile) {
+    let cwd = std::env::current_dir().unwrap_or_default();
+    match (
+        config.project_config_path().filter(|p| p.is_file()),
+        config.global_config_path().filter(|p| p.is_file()),
+    ) {
+        (Some(p), _) => {
+            let path = p.strip_prefix(&cwd).unwrap_or(&p).display().to_string();
+            eprintln!(
+                "using config {}",
+                path.if_supports_color(Stream::Stderr, |t| t.style(DIM))
+            );
+        }
+        (None, Some(g)) => {
+            let path = g.strip_prefix(&cwd).unwrap_or(&g).display().to_string();
+            eprintln!(
+                "using global config {}",
+                path.if_supports_color(Stream::Stderr, |t| t.style(DIM))
+            );
+        }
+        (None, None) => eprintln!("No config found, using default config"),
+    }
+}
+
+/// Resolves a mix of file paths, directories, and glob patterns into a sorted,
+/// deduplicated list of file paths. Non-absolute patterns are resolved relative to root.
+fn resolve_paths(patterns: &[String], root: &Path) -> Vec<PathBuf> {
+    let mut paths = Vec::new();
+    for pattern in patterns {
+        let p = PathBuf::from(pattern);
+        let p = if p.is_absolute() { p } else { root.join(&p) };
+        if p.is_dir() {
+            collect_dir(&p, &mut paths);
+        } else {
+            let pattern = p.to_string_lossy();
+            match glob::glob(&pattern) {
+                Ok(entries) => {
+                    let mut matched = false;
+                    for entry in entries.flatten() {
+                        if entry.is_file() {
+                            paths.push(entry);
+                            matched = true;
+                        } else if entry.is_dir() {
+                            collect_dir(&entry, &mut paths);
+                            matched = true;
+                        }
+                    }
+                    if !matched {
+                        eprintln!("codebook: no match for '{pattern}'");
+                    }
+                }
+                Err(e) => eprintln!("codebook: invalid pattern '{pattern}': {e}"),
+            }
+        }
+    }
+    paths.sort();
+    paths.dedup();
+    paths
+}
+
+fn collect_dir(dir: &Path, out: &mut Vec<PathBuf>) {
+    walkdir::WalkDir::new(dir)
+        .follow_links(false)
+        .into_iter()
+        .flatten()
+        .filter(|e| e.file_type().is_file())
+        .for_each(|e| out.push(e.into_path()));
+}
diff --git a/crates/codebook-lsp/src/main.rs b/crates/codebook-lsp/src/main.rs
index bc055ee..449c174 100644
--- a/crates/codebook-lsp/src/main.rs
+++ b/crates/codebook-lsp/src/main.rs
@@ -1,5 +1,6 @@
 mod file_cache;
 mod init_options;
+mod lint;
 mod lsp;
 mod lsp_logger;
 
@@ -30,14 +31,29 @@ enum Commands {
     Serve {},
     /// Remove server cache
     Clean {},
+    /// Check files for spelling errors
+    Lint {
+        /// Files or glob patterns to spell-check
+        #[arg(required = true)]
+        files: Vec<String>,
+        /// Only report each misspelled word once, ignoring duplicates across files
+        #[arg(short = 'u', long)]
+        unique: bool,
+        /// Show spelling suggestions for each misspelled word
+        #[arg(short = 's', long)]
+        suggest: bool,
+    },
 }
 
 #[tokio::main(flavor = "current_thread")]
 async fn main() {
     // Initialize logger early with stderr output and buffering
-    // Default to INFO level, will be adjusted when LSP client connects
+    // Default to INFO for LSP, WARN for lint (to suppress LSP-oriented noise)
+    let is_lint = std::env::args().nth(1).as_deref() == Some("lint");
     let log_level = match env::var("RUST_LOG").as_deref() {
         Ok("debug") => LevelFilter::Debug,
+        Ok("info") => LevelFilter::Info,
+        _ if is_lint => LevelFilter::Warn,
         _ => LevelFilter::Info,
     };
     LspLogger::init_early(log_level).expect("Failed to initialize early logger");
@@ -58,6 +74,15 @@ async fn main() {
             info!("Cleaning: {:?}", config.cache_dir);
             config.clean_cache()
         }
+        Some(Commands::Lint {
+            files,
+            unique,
+            suggest,
+        }) => {
+            if lint::run_lint(files, root, *unique, *suggest) {
+                std::process::exit(1);
+            }
+        }
         None => {}
     }
 }