diff --git a/.github/workflows/main.yaml b/.github/workflows/main.yaml
index 33179486d..71f6ea762 100644
--- a/.github/workflows/main.yaml
+++ b/.github/workflows/main.yaml
@@ -10,11 +10,7 @@ jobs:
   test-rust:
     name: Rust tests (marzano)
     timeout-minutes: 20
-    strategy:
-      fail-fast: false
-      matrix:
-        os: [nscloud-ubuntu-22.04-amd64-8x32]
-    runs-on: ${{ matrix.os }}
+    runs-on: namespace-profile-standard-ubuntu22-amd64
     permissions:
       contents: "read"
       id-token: "write"
@@ -25,10 +21,8 @@ jobs:
       BUILD_PLATFORM: amd64
     steps:
       - name: clone code
-        uses: actions/checkout@v3
-        with:
-          submodules: true
-          fetch-depth: 0
+        uses: namespacelabs/nscloud-checkout-action@v2
+      - run: nsc git-checkout update-submodules --mirror_base_path=${NSC_GIT_MIRROR} --repository_path=${GITHUB_WORKSPACE} --recurse
       - name: Install Protoc
         run: sudo apt-get install -y protobuf-compiler
       - name: install Rust
@@ -74,19 +68,14 @@ jobs:
   test-rust-wasm:
     name: Rust wasm
     timeout-minutes: 15
-    strategy:
-      fail-fast: false
-    runs-on:
-      - nscloud-ubuntu-22.04-amd64-8x32
+    runs-on: namespace-profile-standard-ubuntu22-amd64
     permissions:
       contents: "read"
       id-token: "write"
     steps:
       - name: clone code
-        uses: actions/checkout@v3
-        with:
-          submodules: true
-          fetch-depth: 0
+        uses: namespacelabs/nscloud-checkout-action@v2
+      - run: nsc git-checkout update-submodules --mirror_base_path=${NSC_GIT_MIRROR} --repository_path=${GITHUB_WORKSPACE} --recurse
       - name: install Rust
         uses: actions-rs/toolchain@v1
         with:
@@ -102,18 +91,14 @@ jobs:
   test-stdlib:
     name: Test the standard library
     timeout-minutes: 30
-    strategy:
-      fail-fast: false
-    runs-on:
-      - nscloud-ubuntu-22.04-amd64-4x16
     permissions:
       contents: "read"
       id-token: "write"
+    runs-on: namespace-profile-standard-ubuntu22-amd64
     steps:
       - name: clone code
-        uses: actions/checkout@v3
-        with:
-          submodules: true
+        uses: namespacelabs/nscloud-checkout-action@v2
+      - run: nsc git-checkout update-submodules --mirror_base_path=${NSC_GIT_MIRROR} --repository_path=${GITHUB_WORKSPACE} --recurse
       - name: install Rust
         uses: actions-rs/toolchain@v1
         with:
diff --git a/crates/cli/src/commands/check.rs b/crates/cli/src/commands/check.rs
index 644bbf022..18ea79cd7 100644
--- a/crates/cli/src/commands/check.rs
+++ b/crates/cli/src/commands/check.rs
@@ -287,6 +287,7 @@ pub(crate) async fn run_check(
                         let reason = Some(MatchReason {
                             metadata_json: None,
                             source: RewriteSource::Gritql,
+                            title: result.pattern.title().map(|s| s.to_string()),
                             name: Some(result.pattern.local_name.to_string()),
                             level: Some(result.pattern.level()),
                             explanation: None,
diff --git a/crates/cli/src/commands/patterns_test.rs b/crates/cli/src/commands/patterns_test.rs
index c27120676..11b8c866e 100644
--- a/crates/cli/src/commands/patterns_test.rs
+++ b/crates/cli/src/commands/patterns_test.rs
@@ -317,7 +317,7 @@ async fn enable_watch_mode(
 
     let testable_patterns_map = testable_patterns
         .iter()
-        .map(|p| (p.local_name.as_ref().unwrap(), p.as_ref()))
+        .map(|p| (p.local_name.as_ref().unwrap(), p))
         .collect::<HashMap<_, _>>();
 
     // event processing
diff --git a/crates/cli/src/result_formatting.rs b/crates/cli/src/result_formatting.rs
index b3be4c155..2f3ee5e96 100644
--- a/crates/cli/src/result_formatting.rs
+++ b/crates/cli/src/result_formatting.rs
@@ -5,7 +5,7 @@ use core::fmt;
 use log::{debug, error, info, warn};
 use marzano_core::api::{
     AllDone, AnalysisLog, AnalysisLogLevel, CreateFile, DoneFile, FileMatchResult, InputFile,
-    Match, MatchResult, PatternInfo, RemoveFile, Rewrite,
+    Match, MatchReason, MatchResult, PatternInfo, RemoveFile, Rewrite,
 };
 use marzano_core::constants::DEFAULT_FILE_NAME;
 use marzano_messenger::output_mode::OutputMode;
@@ -137,6 +137,28 @@ pub fn get_human_error(mut log: AnalysisLog, input_pattern: &str) -> String {
     result
 }
 
+/// Print a header for a match, with the path and (maybe) a title/explanation
+pub fn print_file_header(
+    path: &str,
+    reason: &Option<MatchReason>,
+    f: &mut fmt::Formatter<'_>,
+) -> fmt::Result {
+    let path_title = path.bold();
+    if let Some(r) = reason {
+        if let Some(title) = &r.title {
+            writeln!(f, "{}: {}", path_title, title)?;
+        } else {
+            writeln!(f, "{}", path_title)?;
+        }
+        if let Some(explanation) = &r.explanation {
+            writeln!(f, "  {}", explanation.italic())?;
+        }
+    } else {
+        writeln!(f, "{}", path_title)?;
+    }
+    Ok(())
+}
+
 impl fmt::Display for FormattedResult {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
@@ -165,12 +187,12 @@ impl fmt::Display for FormattedResult {
                 Ok(())
             }
             FormattedResult::Match(m) => {
-                let path_title = m.file_name().bold();
-                writeln!(f, "{}", path_title)?;
+                print_file_header(m.file_name(), &m.reason, f)?;
+
                 let source = m.content();
                 match source {
                     Err(e) => {
-                        writeln!(f, "Could not read file: {}", e)?;
+                        writeln!(f, "Could not read flie: {}", e)?;
                         return Ok(());
                     }
                     Ok(source) => {
@@ -232,24 +254,22 @@ impl fmt::Display for FormattedResult {
                         item.original.source_file, item.rewritten.source_file
                     )
                 };
-                let path_title = path_name.bold();
-                writeln!(f, "{}", path_title)?;
+                print_file_header(&path_name, &item.reason, f)?;
+
                 let result: MatchResult = item.clone().into();
                 let diff = format_result_diff(&result, None);
                 write!(f, "{}", diff)?;
                 Ok(())
             }
             FormattedResult::CreateFile(item) => {
-                let path_title = item.file_name().bold();
+                print_file_header(item.file_name(), &item.reason, f)?;
                 let result: MatchResult = item.clone().into();
-                writeln!(f, "{}", path_title)?;
                 let diff = format_result_diff(&result, None);
                 write!(f, "{}", diff)?;
                 Ok(())
             }
             FormattedResult::RemoveFile(item) => {
-                let path_title = item.file_name().bold();
-                writeln!(f, "{}", path_title)?;
+                print_file_header(item.file_name(), &item.reason, f)?;
                 let result: MatchResult = item.clone().into();
                 let diff = format_result_diff(&result, None);
                 write!(f, "{}", diff)?;
diff --git a/crates/cli_bin/fixtures/.grit/.gitignore b/crates/cli_bin/fixtures/.grit/.gitignore
new file mode 100644
index 000000000..e4fdfb17c
--- /dev/null
+++ b/crates/cli_bin/fixtures/.grit/.gitignore
@@ -0,0 +1,2 @@
+.gritmodules*
+*.log
diff --git a/crates/core/src/api.rs b/crates/core/src/api.rs
index 52a6ba6ba..d8a1c4993 100644
--- a/crates/core/src/api.rs
+++ b/crates/core/src/api.rs
@@ -62,18 +62,12 @@ impl MatchResult {
 /// Make a path look the way provolone expects it to
 /// Removes leading "./", or the root path if it's provided
 fn normalize_path_in_project<'a>(path: &'a str, root_path: Option<&'a PathBuf>) -> &'a str {
-    #[cfg(debug_assertions)]
     if let Some(root_path) = root_path {
-        if !root_path.to_str().unwrap_or_default().ends_with('/') {
-            panic!(
-                "root_path '{}' must end with a slash.",
-                root_path.to_str().unwrap_or_default()
-            );
-        }
-    }
-    if let Some(root_path) = root_path {
-        let root_path = root_path.to_str().unwrap();
-        path.strip_prefix(root_path).unwrap_or(path)
+        let basic = path
+            .strip_prefix(root_path.to_string_lossy().as_ref())
+            .unwrap_or(path);
+        // Stip the leading / if it's there
+        basic.strip_prefix('/').unwrap_or(basic)
     } else {
         path.strip_prefix("./").unwrap_or(path)
     }
@@ -506,7 +500,11 @@ impl FileMatchResult for Rewrite {
 pub struct MatchReason {
     pub metadata_json: Option<String>,
     pub source: RewriteSource,
+    /// The name of the pattern that matched, or another programmatic identifier
     pub name: Option<String>,
+    /// A human-readable title for the match
+    pub title: Option<String>,
+    /// A human-readable explanation of the match
     pub explanation: Option<String>,
     pub level: Option<EnforcementLevel>,
 }
@@ -795,11 +793,13 @@ mod tests {
     }
 
     #[test]
-    #[should_panic]
     fn test_normalize_path_in_project_with_root_no_slash() {
         let path = "/home/user/project/src/main.rs";
         let root_path = PathBuf::from("/home/user/project");
-        normalize_path_in_project(path, Some(&root_path));
+        assert_eq!(
+            normalize_path_in_project(path, Some(&root_path)),
+            "src/main.rs",
+        );
     }
 
     #[test]
diff --git a/crates/core/src/pattern_compiler/compiler.rs b/crates/core/src/pattern_compiler/compiler.rs
index 36230942f..8a48401c1 100644
--- a/crates/core/src/pattern_compiler/compiler.rs
+++ b/crates/core/src/pattern_compiler/compiler.rs
@@ -588,10 +588,9 @@ pub fn get_dependents_of_target_patterns_by_traversal_from_src(
 
     let name_to_filename: BTreeMap<&String, &String> = pattern_file
         .iter()
-        .map(|(k, v)| (k, (v)))
-        .chain(predicate_file.iter().map(|(k, v)| (k, (v))))
-        .chain(function_file.iter().map(|(k, v)| (k, (v))))
-        .chain(foreign_file.iter().map(|(k, v)| (k, (v))))
+        .chain(predicate_file.iter())
+        .chain(function_file.iter())
+        .chain(foreign_file.iter())
         .collect();
 
     let mut traversed_stack = <Vec<String>>::new();
diff --git a/crates/gritmodule/fixtures/pattern_files/.grit/grit.yaml b/crates/gritmodule/fixtures/pattern_files/.grit/grit.yaml
new file mode 100644
index 000000000..d58831a5d
--- /dev/null
+++ b/crates/gritmodule/fixtures/pattern_files/.grit/grit.yaml
@@ -0,0 +1,11 @@
+version: 0.0.1
+patterns:
+  - file: ../docs/guides/version_5_upgrade.md
+  - file: ../docs/guides/something.md
+  - name: remove_console_error
+    level: error
+    body: |
+      engine marzano(0.1)
+      language js
+
+      `console.error($_)` => .
diff --git a/crates/gritmodule/fixtures/pattern_files/docs/guides/something.md b/crates/gritmodule/fixtures/pattern_files/docs/guides/something.md
new file mode 100644
index 000000000..a4dca26bc
--- /dev/null
+++ b/crates/gritmodule/fixtures/pattern_files/docs/guides/something.md
@@ -0,0 +1,82 @@
+---
+title: Compare `null` using  `===` or `!==`
+---
+
+Comparing to `null` needs a type-checking operator (=== or !==), to avoid incorrect results when the value is `undefined`.
+
+tags: #good
+
+```grit
+engine marzano(0.1)
+language js
+
+// We use the syntax-tree node binary_expression to capture all expressions where $a and $b are operated on by "==" or "!=".
+// This code takes advantage of Grit's allowing us to nest rewrites inside match conditions and to match syntax-tree fields on patterns.
+binary_expression($operator, $left, $right) where {
+    $operator <: or  { "==" => `===` , "!=" => `!==` },
+    or { $left <: `null`, $right <: `null`}
+}
+
+```
+
+```
+
+```
+
+## `$val == null` => `$val === null`
+
+```javascript
+if (val == null) {
+  done();
+}
+```
+
+```typescript
+if (val === null) {
+  done();
+}
+```
+
+## `$val != null` => `$val !== null`
+
+```javascript
+if (val != null) {
+  done();
+}
+```
+
+```typescript
+if (val !== null) {
+  done();
+}
+```
+
+## `$val != null` => `$val !== null` into `while`
+
+```javascript
+while (val != null) {
+  did();
+}
+```
+
+```typescript
+while (val !== null) {
+  did();
+}
+```
+
+## Do not change `$val === null`
+
+```javascript
+if (val === null) {
+  done();
+}
+```
+
+## Do not change `$val !== null`
+
+```
+while (val !== null) {
+  doSomething();
+}
+```
diff --git a/crates/gritmodule/fixtures/pattern_files/docs/guides/version_5_upgrade.md b/crates/gritmodule/fixtures/pattern_files/docs/guides/version_5_upgrade.md
new file mode 100644
index 000000000..a4dca26bc
--- /dev/null
+++ b/crates/gritmodule/fixtures/pattern_files/docs/guides/version_5_upgrade.md
@@ -0,0 +1,82 @@
+---
+title: Compare `null` using  `===` or `!==`
+---
+
+Comparing to `null` needs a type-checking operator (=== or !==), to avoid incorrect results when the value is `undefined`.
+
+tags: #good
+
+```grit
+engine marzano(0.1)
+language js
+
+// We use the syntax-tree node binary_expression to capture all expressions where $a and $b are operated on by "==" or "!=".
+// This code takes advantage of Grit's allowing us to nest rewrites inside match conditions and to match syntax-tree fields on patterns.
+binary_expression($operator, $left, $right) where {
+    $operator <: or  { "==" => `===` , "!=" => `!==` },
+    or { $left <: `null`, $right <: `null`}
+}
+
+```
+
+```
+
+```
+
+## `$val == null` => `$val === null`
+
+```javascript
+if (val == null) {
+  done();
+}
+```
+
+```typescript
+if (val === null) {
+  done();
+}
+```
+
+## `$val != null` => `$val !== null`
+
+```javascript
+if (val != null) {
+  done();
+}
+```
+
+```typescript
+if (val !== null) {
+  done();
+}
+```
+
+## `$val != null` => `$val !== null` into `while`
+
+```javascript
+while (val != null) {
+  did();
+}
+```
+
+```typescript
+while (val !== null) {
+  did();
+}
+```
+
+## Do not change `$val === null`
+
+```javascript
+if (val === null) {
+  done();
+}
+```
+
+## Do not change `$val !== null`
+
+```
+while (val !== null) {
+  doSomething();
+}
+```
diff --git a/crates/gritmodule/src/config.rs b/crates/gritmodule/src/config.rs
index 10b2aa128..2b8979ca1 100644
--- a/crates/gritmodule/src/config.rs
+++ b/crates/gritmodule/src/config.rs
@@ -32,15 +32,31 @@ pub struct GritGitHubConfig {
     pub reviewers: Vec<String>,
 }
 
+/// Represents a reference to an external pattern file
 #[derive(Debug, Deserialize)]
+pub struct GritPatternFile {
+    pub file: PathBuf,
+}
+
+/// Pure in-memory representation of the grit config
+#[derive(Debug)]
 pub struct GritConfig {
     pub patterns: Vec<GritDefinitionConfig>,
+    pub pattern_files: Option<Vec<GritPatternFile>>,
     pub github: Option<GritGitHubConfig>,
 }
 
+#[derive(Debug, Deserialize)]
+#[serde(untagged)]
+pub enum GritPatternConfig {
+    File(GritPatternFile),
+    Pattern(GritSerializedDefinitionConfig),
+}
+
+/// Compacted / serialized version of the GritConfig
 #[derive(Debug, Deserialize)]
 pub struct SerializedGritConfig {
-    pub patterns: Vec<GritSerializedDefinitionConfig>,
+    pub patterns: Vec<GritPatternConfig>,
     pub github: Option<GritGitHubConfig>,
 }
 
@@ -78,7 +94,7 @@ pub struct GritDefinitionConfig {
     pub name: String,
     pub body: Option<String>,
     #[serde(flatten)]
-    pub(crate) meta: GritPatternMetadata,
+    pub meta: GritPatternMetadata,
     #[serde(skip)]
     pub kind: Option<DefinitionKind>,
     pub samples: Option<Vec<GritPatternSample>>,
diff --git a/crates/gritmodule/src/parser.rs b/crates/gritmodule/src/parser.rs
index b5c2d0873..37eb8b878 100644
--- a/crates/gritmodule/src/parser.rs
+++ b/crates/gritmodule/src/parser.rs
@@ -48,7 +48,7 @@ impl PatternFileExt {
         }
     }
 
-    fn get_patterns(
+    async fn get_patterns(
         &self,
         file: &mut RichFile,
         source_module: &Option<ModuleRepo>,
@@ -71,14 +71,14 @@ impl PatternFileExt {
                     )
                 })
             }
-            PatternFileExt::Yaml => {
-                get_patterns_from_yaml(file, source_module, root).with_context(|| {
+            PatternFileExt::Yaml => get_patterns_from_yaml(file, source_module, root, "")
+                .await
+                .with_context(|| {
                     format!(
                         "Failed to parse yaml pattern {}",
                         extract_relative_file_path(file, root)
                     )
-                })
-            }
+                }),
         }
     }
 
@@ -103,6 +103,7 @@ pub async fn get_patterns_from_file(
         content,
     };
     ext.get_patterns(&mut file, &source_module, &repo_root)
+        .await
 }
 
 pub fn extract_relative_file_path(file: &RichFile, root: &Option<String>) -> String {
diff --git a/crates/gritmodule/src/resolver.rs b/crates/gritmodule/src/resolver.rs
index 725c02b2d..f4ba854dd 100644
--- a/crates/gritmodule/src/resolver.rs
+++ b/crates/gritmodule/src/resolver.rs
@@ -535,7 +535,8 @@ async fn get_grit_files_for_module(
         Some(config) => {
             if let Some(module) = module {
                 let repo_root = find_repo_root_from(repo_path).await?;
-                get_patterns_from_yaml(&config, &Some(module.to_owned()), &repo_root)?
+                get_patterns_from_yaml(&config, &Some(module.to_owned()), &repo_root, repo_dir)
+                    .await?
             } else {
                 vec![]
             }
@@ -586,7 +587,8 @@ async fn resolve_patterns_for_module(
         Some(config) => {
             if let Some(module) = module {
                 let repo_root = find_repo_root_from(repo_path).await?;
-                get_patterns_from_yaml(&config, &Some(module.to_owned()), &repo_root)?
+                get_patterns_from_yaml(&config, &Some(module.to_owned()), &repo_root, repo_dir)
+                    .await?
             } else {
                 vec![]
             }
@@ -934,4 +936,20 @@ mod tests {
         resolved_patterns.sort_by(|a, b| a.language.to_string().cmp(&b.language.to_string()));
         assert_yaml_snapshot!(resolved_patterns);
     }
+
+    #[tokio::test]
+    async fn finds_patterns_from_custom_pattern_files() {
+        let module_repo = ModuleRepo::from_host_repo("github.com", "getgrit/rewriter").unwrap();
+        let repo_dir = "fixtures/pattern_files";
+        let (mut resolved_patterns, errored_patterns) =
+            super::resolve_patterns(&module_repo, repo_dir, None)
+                .await
+                .unwrap();
+
+        assert_eq!(resolved_patterns.len(), 3);
+        assert_eq!(errored_patterns.len(), 0);
+
+        resolved_patterns.sort_by(|a, b| a.local_name.cmp(&b.local_name));
+        assert_yaml_snapshot!(resolved_patterns);
+    }
 }
diff --git a/crates/gritmodule/src/snapshots/marzano_gritmodule__resolver__tests__finds_patterns_from_custom_pattern_files.snap b/crates/gritmodule/src/snapshots/marzano_gritmodule__resolver__tests__finds_patterns_from_custom_pattern_files.snap
new file mode 100644
index 000000000..1ac553545
--- /dev/null
+++ b/crates/gritmodule/src/snapshots/marzano_gritmodule__resolver__tests__finds_patterns_from_custom_pattern_files.snap
@@ -0,0 +1,284 @@
+---
+source: crates/gritmodule/src/resolver.rs
+expression: resolved_patterns
+---
+- config:
+    name: remove_console_error
+    body: "engine marzano(0.1)\nlanguage js\n\n`console.error($_)` => .\n"
+    level: error
+    title: ~
+    description: ~
+    tags: ~
+    samples: ~
+    path: ".grit/grit.yaml"
+    position:
+      line: 5
+      column: 11
+    raw: ~
+  module:
+    type: Module
+    host: github.com
+    fullName: getgrit/rewriter
+    remote: "https://github.com/getgrit/rewriter.git"
+    providerName: github.com/getgrit/rewriter
+  localName: remove_console_error
+  body: "engine marzano(0.1)\nlanguage js\n\n`console.error($_)` => .\n"
+  kind: pattern
+  language: js
+  visibility: public
+- config:
+    name: something
+    body: "engine marzano(0.1)\nlanguage js\n\n// We use the syntax-tree node binary_expression to capture all expressions where $a and $b are operated on by \"==\" or \"!=\".\n// This code takes advantage of Grit's allowing us to nest rewrites inside match conditions and to match syntax-tree fields on patterns.\nbinary_expression($operator, $left, $right) where {\n    $operator <: or  { \"==\" => `===` , \"!=\" => `!==` },\n    or { $left <: `null`, $right <: `null`}\n}\n\n"
+    level: info
+    title: "Compare `null` using  `===` or `!==`"
+    description: "Comparing to `null` needs a type-checking operator (=== or !==), to avoid incorrect results when the value is `undefined`."
+    tags: ~
+    samples:
+      - name: ~
+        input: "\n"
+        output: ~
+        input_range:
+          start:
+            line: 23
+            column: 1
+          end:
+            line: 24
+            column: 1
+          startByte: 657
+          endByte: 658
+        output_range: ~
+      - name: "`$val == null` => `$val === null`"
+        input: "if (val == null) {\n  done();\n}\n"
+        output: "if (val === null) {\n  done();\n}\n"
+        input_range:
+          start:
+            line: 29
+            column: 1
+          end:
+            line: 32
+            column: 1
+          startByte: 715
+          endByte: 746
+        output_range:
+          start:
+            line: 35
+            column: 1
+          end:
+            line: 38
+            column: 1
+          startByte: 765
+          endByte: 797
+      - name: "`$val != null` => `$val !== null`"
+        input: "if (val != null) {\n  done();\n}\n"
+        output: "if (val !== null) {\n  done();\n}\n"
+        input_range:
+          start:
+            line: 43
+            column: 1
+          end:
+            line: 46
+            column: 1
+          startByte: 854
+          endByte: 885
+        output_range:
+          start:
+            line: 49
+            column: 1
+          end:
+            line: 52
+            column: 1
+          startByte: 904
+          endByte: 936
+      - name: "`$val != null` => `$val !== null` into `while`"
+        input: "while (val != null) {\n  did();\n}\n"
+        output: "while (val !== null) {\n  did();\n}\n"
+        input_range:
+          start:
+            line: 57
+            column: 1
+          end:
+            line: 60
+            column: 1
+          startByte: 1006
+          endByte: 1039
+        output_range:
+          start:
+            line: 63
+            column: 1
+          end:
+            line: 66
+            column: 1
+          startByte: 1058
+          endByte: 1092
+      - name: "Do not change `$val === null`"
+        input: "if (val === null) {\n  done();\n}\n"
+        output: ~
+        input_range:
+          start:
+            line: 71
+            column: 1
+          end:
+            line: 74
+            column: 1
+          startByte: 1145
+          endByte: 1177
+        output_range: ~
+      - name: "Do not change `$val !== null`"
+        input: "while (val !== null) {\n  doSomething();\n}\n"
+        output: ~
+        input_range:
+          start:
+            line: 79
+            column: 1
+          end:
+            line: 82
+            column: 1
+          startByte: 1220
+          endByte: 1262
+        output_range: ~
+    path: ".grit/../docs/guides/something.md"
+    position:
+      line: 10
+      column: 1
+    raw:
+      format: markdown
+      content: "---\ntitle: Compare `null` using  `===` or `!==`\n---\n\nComparing to `null` needs a type-checking operator (=== or !==), to avoid incorrect results when the value is `undefined`.\n\ntags: #good\n\n```grit\nengine marzano(0.1)\nlanguage js\n\n// We use the syntax-tree node binary_expression to capture all expressions where $a and $b are operated on by \"==\" or \"!=\".\n// This code takes advantage of Grit's allowing us to nest rewrites inside match conditions and to match syntax-tree fields on patterns.\nbinary_expression($operator, $left, $right) where {\n    $operator <: or  { \"==\" => `===` , \"!=\" => `!==` },\n    or { $left <: `null`, $right <: `null`}\n}\n\n```\n\n```\n\n```\n\n## `$val == null` => `$val === null`\n\n```javascript\nif (val == null) {\n  done();\n}\n```\n\n```typescript\nif (val === null) {\n  done();\n}\n```\n\n## `$val != null` => `$val !== null`\n\n```javascript\nif (val != null) {\n  done();\n}\n```\n\n```typescript\nif (val !== null) {\n  done();\n}\n```\n\n## `$val != null` => `$val !== null` into `while`\n\n```javascript\nwhile (val != null) {\n  did();\n}\n```\n\n```typescript\nwhile (val !== null) {\n  did();\n}\n```\n\n## Do not change `$val === null`\n\n```javascript\nif (val === null) {\n  done();\n}\n```\n\n## Do not change `$val !== null`\n\n```\nwhile (val !== null) {\n  doSomething();\n}\n```\n"
+  module:
+    type: Module
+    host: github.com
+    fullName: getgrit/rewriter
+    remote: "https://github.com/getgrit/rewriter.git"
+    providerName: github.com/getgrit/rewriter
+  localName: something
+  body: "engine marzano(0.1)\nlanguage js\n\n// We use the syntax-tree node binary_expression to capture all expressions where $a and $b are operated on by \"==\" or \"!=\".\n// This code takes advantage of Grit's allowing us to nest rewrites inside match conditions and to match syntax-tree fields on patterns.\nbinary_expression($operator, $left, $right) where {\n    $operator <: or  { \"==\" => `===` , \"!=\" => `!==` },\n    or { $left <: `null`, $right <: `null`}\n}\n\n"
+  kind: pattern
+  language: js
+  visibility: public
+- config:
+    name: version_5_upgrade
+    body: "engine marzano(0.1)\nlanguage js\n\n// We use the syntax-tree node binary_expression to capture all expressions where $a and $b are operated on by \"==\" or \"!=\".\n// This code takes advantage of Grit's allowing us to nest rewrites inside match conditions and to match syntax-tree fields on patterns.\nbinary_expression($operator, $left, $right) where {\n    $operator <: or  { \"==\" => `===` , \"!=\" => `!==` },\n    or { $left <: `null`, $right <: `null`}\n}\n\n"
+    level: info
+    title: "Compare `null` using  `===` or `!==`"
+    description: "Comparing to `null` needs a type-checking operator (=== or !==), to avoid incorrect results when the value is `undefined`."
+    tags: ~
+    samples:
+      - name: ~
+        input: "\n"
+        output: ~
+        input_range:
+          start:
+            line: 23
+            column: 1
+          end:
+            line: 24
+            column: 1
+          startByte: 657
+          endByte: 658
+        output_range: ~
+      - name: "`$val == null` => `$val === null`"
+        input: "if (val == null) {\n  done();\n}\n"
+        output: "if (val === null) {\n  done();\n}\n"
+        input_range:
+          start:
+            line: 29
+            column: 1
+          end:
+            line: 32
+            column: 1
+          startByte: 715
+          endByte: 746
+        output_range:
+          start:
+            line: 35
+            column: 1
+          end:
+            line: 38
+            column: 1
+          startByte: 765
+          endByte: 797
+      - name: "`$val != null` => `$val !== null`"
+        input: "if (val != null) {\n  done();\n}\n"
+        output: "if (val !== null) {\n  done();\n}\n"
+        input_range:
+          start:
+            line: 43
+            column: 1
+          end:
+            line: 46
+            column: 1
+          startByte: 854
+          endByte: 885
+        output_range:
+          start:
+            line: 49
+            column: 1
+          end:
+            line: 52
+            column: 1
+          startByte: 904
+          endByte: 936
+      - name: "`$val != null` => `$val !== null` into `while`"
+        input: "while (val != null) {\n  did();\n}\n"
+        output: "while (val !== null) {\n  did();\n}\n"
+        input_range:
+          start:
+            line: 57
+            column: 1
+          end:
+            line: 60
+            column: 1
+          startByte: 1006
+          endByte: 1039
+        output_range:
+          start:
+            line: 63
+            column: 1
+          end:
+            line: 66
+            column: 1
+          startByte: 1058
+          endByte: 1092
+      - name: "Do not change `$val === null`"
+        input: "if (val === null) {\n  done();\n}\n"
+        output: ~
+        input_range:
+          start:
+            line: 71
+            column: 1
+          end:
+            line: 74
+            column: 1
+          startByte: 1145
+          endByte: 1177
+        output_range: ~
+      - name: "Do not change `$val !== null`"
+        input: "while (val !== null) {\n  doSomething();\n}\n"
+        output: ~
+        input_range:
+          start:
+            line: 79
+            column: 1
+          end:
+            line: 82
+            column: 1
+          startByte: 1220
+          endByte: 1262
+        output_range: ~
+    path: ".grit/../docs/guides/version_5_upgrade.md"
+    position:
+      line: 10
+      column: 1
+    raw:
+      format: markdown
+      content: "---\ntitle: Compare `null` using  `===` or `!==`\n---\n\nComparing to `null` needs a type-checking operator (=== or !==), to avoid incorrect results when the value is `undefined`.\n\ntags: #good\n\n```grit\nengine marzano(0.1)\nlanguage js\n\n// We use the syntax-tree node binary_expression to capture all expressions where $a and $b are operated on by \"==\" or \"!=\".\n// This code takes advantage of Grit's allowing us to nest rewrites inside match conditions and to match syntax-tree fields on patterns.\nbinary_expression($operator, $left, $right) where {\n    $operator <: or  { \"==\" => `===` , \"!=\" => `!==` },\n    or { $left <: `null`, $right <: `null`}\n}\n\n```\n\n```\n\n```\n\n## `$val == null` => `$val === null`\n\n```javascript\nif (val == null) {\n  done();\n}\n```\n\n```typescript\nif (val === null) {\n  done();\n}\n```\n\n## `$val != null` => `$val !== null`\n\n```javascript\nif (val != null) {\n  done();\n}\n```\n\n```typescript\nif (val !== null) {\n  done();\n}\n```\n\n## `$val != null` => `$val !== null` into `while`\n\n```javascript\nwhile (val != null) {\n  did();\n}\n```\n\n```typescript\nwhile (val !== null) {\n  did();\n}\n```\n\n## Do not change `$val === null`\n\n```javascript\nif (val === null) {\n  done();\n}\n```\n\n## Do not change `$val !== null`\n\n```\nwhile (val !== null) {\n  doSomething();\n}\n```\n"
+  module:
+    type: Module
+    host: github.com
+    fullName: getgrit/rewriter
+    remote: "https://github.com/getgrit/rewriter.git"
+    providerName: github.com/getgrit/rewriter
+  localName: version_5_upgrade
+  body: "engine marzano(0.1)\nlanguage js\n\n// We use the syntax-tree node binary_expression to capture all expressions where $a and $b are operated on by \"==\" or \"!=\".\n// This code takes advantage of Grit's allowing us to nest rewrites inside match conditions and to match syntax-tree fields on patterns.\nbinary_expression($operator, $left, $right) where {\n    $operator <: or  { \"==\" => `===` , \"!=\" => `!==` },\n    or { $left <: `null`, $right <: `null`}\n}\n\n"
+  kind: pattern
+  language: js
+  visibility: public
diff --git a/crates/gritmodule/src/yaml.rs b/crates/gritmodule/src/yaml.rs
index 14ccde9f3..beea33572 100644
--- a/crates/gritmodule/src/yaml.rs
+++ b/crates/gritmodule/src/yaml.rs
@@ -1,8 +1,11 @@
 use anyhow::{bail, Result};
 use grit_util::Position;
 use marzano_util::rich_path::RichFile;
-use std::{collections::HashSet, path::Path};
-use tokio::fs;
+use std::{
+    collections::HashSet,
+    path::{Path, PathBuf},
+};
+use tokio::{fs, task};
 
 use crate::{
     config::{
@@ -10,7 +13,7 @@ use crate::{
         ModuleGritPattern, SerializedGritConfig, CONFIG_FILE_NAMES, REPO_CONFIG_DIR_NAME,
     },
     fetcher::ModuleRepo,
-    parser::extract_relative_file_path,
+    parser::{extract_relative_file_path, get_patterns_from_file, PatternFileExt},
 };
 
 pub fn get_grit_config(source: &str, source_path: &str) -> Result<GritConfig> {
@@ -25,24 +28,44 @@ pub fn get_grit_config(source: &str, source_path: &str) -> Result<GritConfig> {
         }
     };
 
+    let mut patterns = Vec::new();
+    let mut pattern_files = Vec::new();
+
+    for pattern in serialized.patterns.into_iter() {
+        match pattern {
+            crate::config::GritPatternConfig::File(file) => {
+                pattern_files.push(file);
+            }
+            crate::config::GritPatternConfig::Pattern(p) => {
+                patterns.push(GritDefinitionConfig::from_serialized(
+                    p,
+                    source_path.to_string(),
+                ));
+            }
+        }
+    }
+
     let new_config = GritConfig {
         github: serialized.github,
-        patterns: serialized
-            .patterns
-            .into_iter()
-            .map(|p| GritDefinitionConfig::from_serialized(p, source_path.to_string()))
-            .collect(),
+        pattern_files: if pattern_files.is_empty() {
+            None
+        } else {
+            Some(pattern_files)
+        },
+        patterns,
     };
 
     Ok(new_config)
 }
 
-pub fn get_patterns_from_yaml(
+pub async fn get_patterns_from_yaml(
     file: &RichFile,
     source_module: &Option<ModuleRepo>,
     root: &Option<String>,
+    repo_dir: &str,
 ) -> Result<Vec<ModuleGritPattern>> {
-    let mut config = get_grit_config(&file.content, &extract_relative_file_path(file, root))?;
+    let grit_path = extract_relative_file_path(file, root);
+    let mut config = get_grit_config(&file.content, &grit_path)?;
 
     for pattern in config.patterns.iter_mut() {
         pattern.kind = Some(DefinitionKind::Pattern);
@@ -50,11 +73,41 @@ pub fn get_patterns_from_yaml(
         pattern.position = Some(Position::from_byte_index(&file.content, offset));
     }
 
-    config
+    let patterns = config
         .patterns
         .into_iter()
         .map(|pattern| pattern_config_to_model(pattern, source_module))
-        .collect()
+        .collect();
+
+    if config.pattern_files.is_none() {
+        return patterns;
+    }
+
+    let mut patterns = patterns?;
+    let mut file_readers = Vec::new();
+
+    for pattern_file in config.pattern_files.unwrap() {
+        let pattern_file = PathBuf::from(repo_dir)
+            .join(REPO_CONFIG_DIR_NAME)
+            .join(&pattern_file.file);
+        let extension = PatternFileExt::from_path(&pattern_file);
+        if extension.is_none() {
+            continue;
+        }
+        let extension = extension.unwrap();
+        let source_module = source_module.clone();
+        file_readers.push(task::spawn_blocking(move || {
+            tokio::runtime::Runtime::new().unwrap().block_on(async {
+                get_patterns_from_file(pattern_file, source_module, extension).await
+            })
+        }));
+    }
+
+    for file_reader in file_readers {
+        patterns.extend(file_reader.await??);
+    }
+
+    Ok(patterns)
 }
 
 pub fn extract_grit_modules(content: &str, path: &str) -> Result<Vec<String>> {
@@ -136,8 +189,8 @@ patterns:
         }
     }
 
-    #[test]
-    fn gets_module_patterns() {
+    #[tokio::test]
+    async fn gets_module_patterns() {
         let grit_yaml = RichFile {
             path: String::new(),
             content: r#"version: 0.0.1
@@ -163,7 +216,9 @@ github:
             .to_string(),
         };
         let repo = Default::default();
-        let patterns = get_patterns_from_yaml(&grit_yaml, &repo, &None).unwrap();
+        let patterns = get_patterns_from_yaml(&grit_yaml, &repo, &None, "getgrit/rewriter")
+            .await
+            .unwrap();
         assert_eq!(patterns.len(), 4);
         assert_yaml_snapshot!(patterns);
     }
diff --git a/crates/language/src/target_language.rs b/crates/language/src/target_language.rs
index 3dd0852db..6b6040dcf 100644
--- a/crates/language/src/target_language.rs
+++ b/crates/language/src/target_language.rs
@@ -205,7 +205,7 @@ impl PatternLanguage {
             PatternLanguage::Rust => &["rs"],
             PatternLanguage::Ruby => &["rb"],
             PatternLanguage::Solidity => &["sol"],
-            PatternLanguage::Hcl => &["hcl", "tf"],
+            PatternLanguage::Hcl => &["hcl", "tf", "tfvars"],
             PatternLanguage::Yaml => &["yaml", "yml"],
             PatternLanguage::Sql => &["sql"],
             PatternLanguage::Vue => &["vue"],
@@ -260,7 +260,7 @@ impl PatternLanguage {
             "rs" => Some(Self::Rust),
             "rb" => Some(Self::Ruby),
             "sol" => Some(Self::Solidity),
-            "hcl" | "tf" => Some(Self::Hcl),
+            "hcl" | "tf" | "tfvars" => Some(Self::Hcl),
             "yaml" | "yml" => Some(Self::Yaml),
             "sql" => Some(Self::Sql),
             "vue" => Some(Self::Vue),