Add PR head content fetch support and documentation clarification

README.md

@@ -900,7 +900,7 @@ export GITHUB_MCP_TOOL_ADD_ISSUE_COMMENT_DESCRIPTION="an alternative description
 - **get_file_contents** - Get file or directory contents
   - `owner`: Repository owner (username or organization) (string, required)
   - `path`: Path to file/directory (directories must end with a slash '/') (string, required)
-  - `ref`: Accepts optional git refs such as `refs/tags/{tag}`, `refs/heads/{branch}` or `refs/pull/{pr_number}/head` (string, optional)
+  - `ref`: Accepts optional git refs such as `refs/tags/{tag}`, `refs/heads/{branch}` or `refs/pull/{pr_number}/head` (string, optional). For example, use `refs/pull/123/head` to fetch content from a pull request head.
   - `repo`: Repository name (string, required)
   - `sha`: Accepts optional commit SHA. If specified, it will be used instead of ref (string, optional)
 

pkg/github/repositories_test.go

@@ -167,6 +167,37 @@ func Test_GetFileContents(t *testing.T) {
 			expectError:    false,
 			expectedResult: mcp.NewToolResultError("Failed to get file contents. The path does not point to a file or directory, or the file does not exist in the repository."),
 		},
+		{
+			name: "successful PR head content fetch",
+			mockedClient: mock.NewMockedHTTPClient(
+				mock.WithRequestMatchHandler(
+					mock.GetReposPullsByOwnerByRepoByPullNumber,
+					http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+						w.Header().Set("Content-Type", "application/json")
+						_, _ = w.Write([]byte(`{"head":{"sha":"prsha"}}`))
+					}),
+				),
+				mock.WithRequestMatchHandler(
+					raw.GetRawReposContentsByOwnerByRepoBySHAByPath,
+					http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+						w.Header().Set("Content-Type", "text/plain")
+						_, _ = w.Write([]byte("PR content"))
+					}),
+				),
+			),
+			requestArgs: map[string]interface{}{
+				"owner": "owner",
+				"repo":  "repo",
+				"path":  "file.txt",
+				"ref":   "refs/pull/5/head",
+			},
+			expectError: false,
+			expectedResult: mcp.TextResourceContents{
+				URI:      "repo://owner/repo/sha/prsha/contents/file.txt",
+				Text:     "PR content",
+				MIMEType: "text/plain",
+			},
+		},
 	}
 
 	for _, tc := range tests {

pkg/github/repository_resource_test.go

@@ -278,3 +278,9 @@ func Test_GetRepositoryResourceTagContent(t *testing.T) {
 	tmpl, _ := GetRepositoryResourceTagContent(nil, stubGetRawClientFn(mockRawClient), translations.NullTranslationHelper)
 	require.Equal(t, "repo://{owner}/{repo}/refs/tags/{tag}/contents{/path*}", tmpl.URITemplate.Raw())
 }
+
+func Test_GetRepositoryResourcePrContent(t *testing.T) {
+	mockRawClient := raw.NewClient(github.NewClient(nil), &url.URL{})
+	tmpl, _ := GetRepositoryResourcePrContent(nil, stubGetRawClientFn(mockRawClient), translations.NullTranslationHelper)
+	require.Equal(t, "repo://{owner}/{repo}/refs/pull/{prNumber}/head/contents{/path*}", tmpl.URITemplate.Raw())
+}