diff --git a/app/pkg/agent/edit_file_prompt.tmpl b/app/pkg/agent/edit_file_prompt.tmpl
new file mode 100644
index 0000000..96e2bc4
--- /dev/null
+++ b/app/pkg/agent/edit_file_prompt.tmpl
@@ -0,0 +1,14 @@
+# Edit File Snippet Task
+
+You will be given a snippet of a file. You will be asked to make changes to that snippet.
+Output the modified snippet and nothing else.
+Do not make any changes that you aren't explicitly asked to make.
+Do not add additional markdown formatting such as putting the snippet in a code block.
+
+<changes>
+{{.Changes}}
+</changes>
+
+<snippet>
+{{.Text}}
+</snippet>
diff --git a/app/pkg/agent/long_files.go b/app/pkg/agent/long_files.go
new file mode 100644
index 0000000..f8c89cc
--- /dev/null
+++ b/app/pkg/agent/long_files.go
@@ -0,0 +1,62 @@
+package agent
+
+import (
+	"bufio"
+	_ "embed"
+	"github.com/jlewi/monogo/helpers"
+	"os"
+	"strings"
+	"text/template"
+)
+
+//go:embed edit_file_prompt.tmpl
+var editPrompt string
+
+var (
+	editTemplate = template.Must(template.New("prompt").Parse(editPrompt))
+)
+
+type editPromptInput struct {
+	Changes string
+	Text    string
+}
+
+// FileSnippet holds the start and end lines and the actual text of the segment.
+type FileSnippet struct {
+	StartLine int
+	EndLine   int
+	Text      string
+}
+
+// ReadFileSegment reads the file at filePath and returns the lines between startLine and endLine (inclusive) as a FileSegment.
+func ReadFileSegment(filePath string, startLine, endLine int) (FileSnippet, error) {
+	file, err := os.Open(filePath)
+	if err != nil {
+		return FileSnippet{}, err
+	}
+	defer helpers.DeferIgnoreError(file.Close)
+
+	scanner := bufio.NewScanner(file)
+	var textBuilder strings.Builder
+	currentLine := 0
+
+	for scanner.Scan() {
+		currentLine++
+		if currentLine >= startLine && currentLine <= endLine {
+			textBuilder.WriteString(scanner.Text() + "\n")
+		}
+		if currentLine > endLine {
+			break
+		}
+	}
+
+	if err := scanner.Err(); err != nil {
+		return FileSnippet{}, err
+	}
+
+	return FileSnippet{
+		StartLine: startLine,
+		EndLine:   endLine,
+		Text:      textBuilder.String(),
+	}, nil
+}
diff --git a/app/pkg/agent/long_files_test.go b/app/pkg/agent/long_files_test.go
new file mode 100644
index 0000000..52ac200
--- /dev/null
+++ b/app/pkg/agent/long_files_test.go
@@ -0,0 +1,118 @@
+package agent
+
+import (
+	"context"
+	"fmt"
+	"github.com/jlewi/foyle/app/pkg/config"
+	"github.com/jlewi/foyle/app/pkg/oai"
+	"github.com/pkg/errors"
+	"github.com/sashabaranov/go-openai"
+	"github.com/sergi/go-diff/diffmatchpatch"
+	"go.uber.org/zap"
+	"os"
+	"strings"
+	"testing"
+)
+
+func run() error {
+	inputFile := "/Users/jlewi/tmp/clusters.tf"
+
+	if err := config.InitViper(nil); err != nil {
+		return errors.Wrapf(err, "Error initializing viper")
+	}
+
+	lConfig := zap.NewDevelopmentConfig()
+	l, err := lConfig.Build()
+	if err != nil {
+		return errors.Wrapf(err, "Error creating logger")
+	}
+
+	zap.ReplaceGlobals(l)
+
+	cfg := config.GetConfig()
+
+	client, err := oai.NewClient(*cfg)
+
+	if err != nil {
+		return errors.Wrapf(err, "Error creating OpenAI client")
+	}
+
+	segment, err := ReadFileSegment(inputFile, 5570, 5594)
+	if err != nil {
+		return errors.Wrapf(err, "Error reading file segment")
+	}
+
+	var sb strings.Builder
+	input := editPromptInput{
+		Changes: "Change the cluster u35 to use the region spaincentral. Add the label owner=foo to the cluster",
+		Text:    segment.Text,
+	}
+
+	if err := editTemplate.Execute(&sb, input); err != nil {
+		return errors.Wrapf(err, "Failed to execute prompt template")
+	}
+
+	messages := []openai.ChatCompletionMessage{
+		{Role: openai.ChatMessageRoleUser,
+			Content: sb.String(),
+		},
+	}
+	request := openai.ChatCompletionRequest{
+		Model:       openai.GPT4oMini,
+		Messages:    messages,
+		MaxTokens:   8000,
+		Temperature: temperature,
+	}
+
+	resp, err := client.CreateChatCompletion(context.Background(), request)
+	if err != nil {
+		return errors.Wrapf(err, "Error calling OpenAI")
+	}
+
+	if len(resp.Choices) != 1 {
+		return errors.Errorf("Expected 1 choice but got %v", len(resp.Choices))
+	}
+
+	output := resp.Choices[0].Message.Content
+	fmt.Printf("ChatGPT Output:\n%v\n", output)
+
+	// Compute a diff between the original text and the output
+	dmp := diffmatchpatch.New()
+
+	//diffs := dmp.DiffMain(segment.Text, output, false)
+	//
+	//// Create a patch
+	//patches := dmp.PatchMake(segment.Text, diffs)
+
+	patches := dmp.PatchMake(segment.Text, output)
+
+	//// Convert the diff to unified format
+	//patch, err := diff.ToUnified(ud, unifiedDiff)
+	//if err != nil {
+	//	fmt.Println("Error generating unified diff:", err)
+	//	return
+	//}
+	for _, p := range patches {
+		fmt.Printf("Patch:\n%v\n", p.String())
+	}
+
+	// TODO(jeremy): How do we adjust the patch to be relative to the original file?
+	// Maybe we should just replace the original lines with the output lines.
+	// if we wanted to we could then compute a diff between the modified and aligned file.
+	// So our patch format should be a start and end line that will be replaced with our fragment.
+	// This is human readable.
+
+	return nil
+}
+
+func Test_LongFiles(t *testing.T) {
+	// The purpose of this test is to experiment with different patterns for modifying very long (e.g. 8K-10K lines)
+	// files. Such as Terraform files
+	if os.Getenv("GITHUB_ACTIONS") != "" {
+		t.Skipf("Test is skipped in GitHub actions")
+	}
+
+	if err := run(); err != nil {
+		t.Fatalf("Error running test: %v", err)
+	}
+}