diff --git a/README.md b/README.md
index c8f4171..649d99c 100644
--- a/README.md
+++ b/README.md
@@ -50,10 +50,11 @@ Each pattern value may include [wildcards](https://fishshell.com/docs/current/la
 
 Configure the action using the following inputs:
 
-| Name         | Description                            | Default               |
-|--------------|----------------------------------------|-----------------------|
-| `patterns`   | A space-separated list of file patterns to match against when running syntax checks; each pattern may include [wildcards](https://fishshell.com/docs/current/language.html#expand-wildcard) and/or [brace expansions](https://fishshell.com/docs/current/language.html?highlight=brace+expansion#brace-expansion) | `**.fish` |
-| `title`      | The title to display in the [job summary](#job-summary); can be used to distinguish multiple summaries generated from a single workflow  | `Syntax check results` |
+| Name          | Description                            | Default               |
+|---------------|----------------------------------------|-----------------------|
+| `annotations` | The string value `'true'` or `'false'` indicating whether to enable [annotations](#annotations) or not | `true` |
+| `patterns`    | A space-separated list of file patterns to match against when running syntax checks; each pattern may include [wildcards](https://fishshell.com/docs/current/language.html#expand-wildcard) and/or [brace expansions](https://fishshell.com/docs/current/language.html?highlight=brace+expansion#brace-expansion) | `**.fish` |
+| `title`       | The title to display in the [job summary](#job-summary); can be used to distinguish multiple summaries generated from a single workflow  | `Syntax check results` |
 
 ## Outputs
 
@@ -65,11 +66,23 @@ The following outputs are made available to subsequent steps in a workflow:
 | `passed` | The number of files that passed syntax checks |
 | `failed` | The number of files that failed syntax checks |
 
+## Annotations
+
+Syntax issues identified by this action are displayed as [annotations](https://github.blog/news-insights/product-news/introducing-check-runs-and-annotations/) on the workflow summary page:
+
+<img alt="Workflow summary annotations" src="images/annotations-workflow-summary.png" width="909">
+
+Annotations are also displayed directly alongside the code in the 'Files changed' tab of pull requests:
+
+<img alt="Pull request annotations" src="images/annotations-pull-request.png" width="909">
+
+This behaviour can be disabled by setting the `annotations` input to `false`.
+
 ## Job summary
 
 This action generates a [job summary](https://github.blog/news-insights/product-news/supercharging-github-actions-with-job-summaries/) at run-time which can be viewed from the workflow run summary page:
 
-<img alt="job-summary" src="images/job-summary.png" width="909">
+<img alt="Job summary" src="images/job-summary.png" width="909">
 
 ## Action versions
 
diff --git a/action.yml b/action.yml
index 899ef5a..2f7c96e 100644
--- a/action.yml
+++ b/action.yml
@@ -4,6 +4,10 @@ branding:
   icon: 'check'
   color: 'green'
 inputs:
+  annotations:
+    description: 'Display annotations for syntax errors in workflow summary and pull request checks'
+    required: false
+    default: 'true'
   title:
     description: 'Title to display in job summary'
     required: false
@@ -28,15 +32,17 @@ runs:
     - name: Syntax check fish shell files
       id: syntax-check
       env:
+        ANNOTATIONS: ${{ inputs.annotations }}
         TITLE: ${{ inputs.title }}
         PATTERNS: ${{ inputs.patterns }}
       run: |
         set -gx TERM xterm-256color
 
-        set -l passed 0
-        set -l failed 0
-
         set title "$TITLE"
+        set annotations "$ANNOTATIONS"
+
+        set passed 0
+        set failed 0
 
         for pattern in (string split --no-empty -- " " $PATTERNS)
             set -l escaped (string escape --style=script --no-quoted -- $pattern)
@@ -46,13 +52,20 @@ runs:
 
             for file in $files
                 echo -n "  "
-                set output (fish --no-execute $file 2>&1)
+                set -l output (fish --no-execute $file 2>&1)
                 if test $status -ne 0
                     set_color red; and echo -n "✖"; and set_color normal
                     echo " $file"
                     for line in (string split -- $output)
                         echo "      $line"
                     end
+
+                    if test "$annotations" = "true"
+                        string match --regex --groups-only '^(?<file>.+)\s+\(line\s+(?<line>[0-9]+)\):\s+(?<message>.+)' $output
+                        set -l title "Syntax issue"
+                        echo "::error file=$file,line=$line,title=$title::$message"
+                    end
+
                     set failed (math $failed + 1)
                 else
                     set_color green; and echo -n "✔"; and set_color normal
@@ -62,7 +75,7 @@ runs:
             end
         end
 
-        set -l total (math $passed + $failed)
+        set total (math $passed + $failed)
 
         echo
         set_color green; and echo -n "passed: $passed"; and set_color normal
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