diff --git a/internal/gaby/overview.go b/internal/gaby/overview.go
index 7f6d582..e2ae1ec 100644
--- a/internal/gaby/overview.go
+++ b/internal/gaby/overview.go
@@ -67,7 +67,7 @@
 		overviewForm: form,
 		Result: &overviewResult{
 			IssueOverviewResult: *overview,
-			OverviewHTML:        htmlutil.MarkdownToSafeHTML(overview.Overview),
+			OverviewHTML:        htmlutil.MarkdownToSafeHTML(overview.Overview.Overview),
 		},
 	}
 }
diff --git a/internal/gaby/templates_test.go b/internal/gaby/templates_test.go
index 12e2dd0..a396dcc 100644
--- a/internal/gaby/templates_test.go
+++ b/internal/gaby/templates_test.go
@@ -19,6 +19,7 @@
 	"golang.org/x/net/html/atom"
 	"golang.org/x/oscar/internal/actions"
 	"golang.org/x/oscar/internal/github"
+	"golang.org/x/oscar/internal/llmapp"
 	"golang.org/x/oscar/internal/search"
 )
 
@@ -40,7 +41,10 @@
 				IssueOverviewResult: github.IssueOverviewResult{
 					URL:         "https://example.com",
 					NumComments: 2,
-					Overview:    "an overview",
+					Overview: &llmapp.OverviewResult{
+						Overview: "an overview",
+						Prompt:   []string{"a prompt"},
+					},
 				},
 				OverviewHTML: safehtml.HTMLEscaped("an overview"),
 			}}},
diff --git a/internal/gaby/tmpl/overviewpage.tmpl b/internal/gaby/tmpl/overviewpage.tmpl
index 9016298..800f46d 100644
--- a/internal/gaby/tmpl/overviewpage.tmpl
+++ b/internal/gaby/tmpl/overviewpage.tmpl
@@ -66,7 +66,7 @@
 		<div class="toggle" onclick="togglePrompt()">[show prompt]</div>
 		<div id="prompt">
 			<ul>
-				{{- range .Prompt -}}
+				{{- range .Overview.Prompt -}}
 				<li>
 					<pre>{{.}}</pre>
 				</li>
diff --git a/internal/github/overview.go b/internal/github/overview.go
index b1e8bcd..a73a4ee 100644
--- a/internal/github/overview.go
+++ b/internal/github/overview.go
@@ -16,57 +16,45 @@
 // It contains the generated overview and metadata about
 // the issue.
 type IssueOverviewResult struct {
-	URL         string   // the issue's URL
-	NumComments int      // number of comments for this issue
-	Overview    string   // the LLM-generated issue and comment summary
-	Prompt      []string // the prompt(s) used to generate the result
+	URL         string                 // the issue's URL
+	NumComments int                    // number of comments for this issue
+	Overview    *llmapp.OverviewResult // the LLM-generated issue and comment summary
 }
 
 // IssueOverview returns an LLM-generated overview of the issue and its comments.
 // It does not make any requests to GitHub; the issue and comment data must already
 // be stored in db.
 func IssueOverview(ctx context.Context, g llm.TextGenerator, db storage.DB, project string, issue int64) (*IssueOverviewResult, error) {
-	var docs []*llmapp.Doc
-	var m issueMetadata
+	var post *llmapp.Doc
+	var comments []*llmapp.Doc
 	for e := range events(db, project, issue, issue) {
-		m.update(e)
-		doc := e.toLLMDoc()
+		doc, isIssue := e.toLLMDoc()
 		if doc == nil {
 			continue
 		}
-		docs = append(docs, doc)
+		if isIssue {
+			post = doc
+			continue
+		}
+		comments = append(comments, doc)
 	}
-	overview, err := llmapp.Overview(ctx, g, llmapp.PostAndComments, docs...)
+	overview, err := llmapp.PostOverview(ctx, g, post, comments)
 	if err != nil {
 		return nil, err
 	}
 	return &IssueOverviewResult{
-		URL:         m.url,
-		NumComments: m.numComments,
+		URL:         post.URL,
+		NumComments: len(comments),
 		Overview:    overview,
-		Prompt:      llmapp.OverviewPrompt(llmapp.PostAndComments, docs),
 	}, nil
 }
 
-type issueMetadata struct {
-	url         string
-	numComments int
-}
-
-// update updates the issueMetadata given the event.
-func (m *issueMetadata) update(e *Event) {
-	switch v := e.Typed.(type) {
-	case *Issue:
-		m.url = v.HTMLURL
-	case *IssueComment:
-		m.numComments++
-	}
-}
-
 // toLLMDoc converts an Event to a format that can be used as
 // an input to an LLM.
-// It returns nil if the Event cannot be converted to a document.
-func (e *Event) toLLMDoc() *llmapp.Doc {
+// isIssue is true if the event represents a GitHub issue (as opposed to
+// a comment or another event).
+// It returns (nil, false) if the Event cannot be converted to a document.
+func (e *Event) toLLMDoc() (_ *llmapp.Doc, isIssue bool) {
 	switch v := e.Typed.(type) {
 	case *Issue:
 		return &llmapp.Doc{
@@ -75,7 +63,7 @@
 			Author: v.User.Login,
 			Title:  v.Title,
 			Text:   v.Body,
-		}
+		}, true
 	case *IssueComment:
 		return &llmapp.Doc{
 			Type:   "issue comment",
@@ -83,7 +71,7 @@
 			Author: v.User.Login,
 			// no title
 			Text: v.Body,
-		}
+		}, false
 	}
-	return nil
+	return nil, false
 }
diff --git a/internal/github/overview_test.go b/internal/github/overview_test.go
index 137a590..6dc8cd7 100644
--- a/internal/github/overview_test.go
+++ b/internal/github/overview_test.go
@@ -33,13 +33,17 @@
 	check(c.Add("robpike/ivy"))
 	check(c.Sync(ctx))
 
-	got, err := IssueOverview(ctx, llm.EchoTextGenerator(), db, "robpike/ivy", 19)
+	echo := llm.EchoTextGenerator()
+
+	got, err := IssueOverview(ctx, echo, db, "robpike/ivy", 19)
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	prompt := llmapp.OverviewPrompt(llmapp.PostAndComments, []*llmapp.Doc{
-		{
+	// This merely checks that the correct call to [llmapp.PostOverview] is made.
+	// The internals of [llmapp.PostOverview] are tested in the llmapp package.
+	wantOverview, err := llmapp.PostOverview(ctx, echo,
+		&llmapp.Doc{
 			Type:   "issue",
 			URL:    "https://github.com/robpike/ivy/issues/19",
 			Author: "xunshicheng",
@@ -50,25 +54,27 @@
 could you get me a hand！
 `,
 		},
-		{
-			Type:   "issue comment",
-			URL:    "https://github.com/robpike/ivy/issues/19#issuecomment-169157303",
-			Author: "robpike",
-			Text: `See the import comment, or listen to the error message. Ivy uses a custom import.
+		[]*llmapp.Doc{
+			{
+				Type:   "issue comment",
+				URL:    "https://github.com/robpike/ivy/issues/19#issuecomment-169157303",
+				Author: "robpike",
+				Text: `See the import comment, or listen to the error message. Ivy uses a custom import.
 
 go get robpike.io/ivy
 
 It is a fair point though that this should be explained in the README. I will fix that.
 `,
-		},
-	})
-	overview := llm.EchoResponse(prompt...)
+			},
+		})
+	if err != nil {
+		t.Fatal(err)
+	}
 
 	want := &IssueOverviewResult{
 		URL:         "https://github.com/robpike/ivy/issues/19",
-		Overview:    overview,
+		Overview:    wantOverview,
 		NumComments: 1,
-		Prompt:      prompt,
 	}
 
 	if diff := cmp.Diff(got, want); diff != "" {
diff --git a/internal/llmapp/overview.go b/internal/llmapp/overview.go
index f4bc6e0..57e9075 100644
--- a/internal/llmapp/overview.go
+++ b/internal/llmapp/overview.go
@@ -33,24 +33,55 @@
 	Text  string `json:"text"` // required
 }
 
+// OverviewResult is the result of [Overview] or [PostOverview].
+type OverviewResult struct {
+	Overview string   // the LLM-generated summary
+	Prompt   []string // the prompt(s) used to generate the result
+}
+
 // Overview returns an LLM-generated overview of the given documents,
 // styled with markdown.
+// Overview returns an error if no documents are provided or the LLM is unable
+// to generate a response.
+func Overview(ctx context.Context, g llm.TextGenerator, docs ...*Doc) (*OverviewResult, error) {
+	return overview(ctx, g, documents, docs)
+}
+
+// PostOverview returns an LLM-generated overview of the given post and comments,
+// styled with markdown.
+// PostOverview returns an error if no post is provided or the LLM is unable to generate a response.
+func PostOverview(ctx context.Context, g llm.TextGenerator, post *Doc, comments []*Doc) (*OverviewResult, error) {
+	if post == nil {
+		return nil, errors.New("llmapp PostOverview: no post")
+	}
+	return overview(ctx, g, postAndComments, append([]*Doc{post}, comments...))
+}
+
+// overview returns an LLM-generated overview of the given documents,
+// styled with markdown.
 // The kind argument is a descriptor for the given documents, used to add
 // additional context to the LLM prompt.
 // Overview returns an error if no documents are provided or the LLM is unable
 // to generate a response.
-// TODO(tatianabradley): Chunk large prompts.
-func Overview(ctx context.Context, g llm.TextGenerator, kind docsKind, docs ...*Doc) (string, error) {
+func overview(ctx context.Context, g llm.TextGenerator, kind docsKind, docs []*Doc) (*OverviewResult, error) {
 	if len(docs) == 0 {
-		return "", errors.New("llmapp.Overview: no documents")
+		return nil, errors.New("llmapp overview: no documents")
 	}
-	return g.GenerateText(ctx, OverviewPrompt(kind, docs)...)
+	prompt := overviewPrompt(kind, docs)
+	overview, err := g.GenerateText(ctx, prompt...)
+	if err != nil {
+		return nil, err
+	}
+	return &OverviewResult{
+		Overview: overview,
+		Prompt:   prompt,
+	}, nil
 }
 
-// OverviewPrompt converts the given docs into a slice of
+// overviewPrompt converts the given docs into a slice of
 // text prompts, followed by an instruction prompt based
 // on the documents kind.
-func OverviewPrompt(kind docsKind, docs []*Doc) []string {
+func overviewPrompt(kind docsKind, docs []*Doc) []string {
 	var inputs = make([]string, len(docs))
 	for i, d := range docs {
 		inputs[i] = string(storage.JSON(d))
@@ -59,15 +90,14 @@
 }
 
 // docsKind is a descriptor for a group of documents.
-// unexported so that clients must use a predefined kind.
-type docsKind struct{ name string }
+type docsKind string
 
 var (
 	// Represents a group of documents of an unspecified kind.
-	Documents docsKind = docsKind{"documents"}
+	documents docsKind = "documents"
 	// The documents represent a post and comments/replies
 	// on that post. For example, a GitHub issue and its comments.
-	PostAndComments docsKind = docsKind{"post_and_comments"}
+	postAndComments docsKind = "post_and_comments"
 )
 
 //go:embed prompts/*.tmpl
@@ -78,7 +108,7 @@
 // document kind.
 func (k docsKind) instructions() string {
 	w := &strings.Builder{}
-	err := tmpls.ExecuteTemplate(w, k.name, nil)
+	err := tmpls.ExecuteTemplate(w, string(k), nil)
 	if err != nil {
 		// unreachable except bug in this package
 		panic(err)
diff --git a/internal/llmapp/overview_test.go b/internal/llmapp/overview_test.go
index 2280f0d..9034ecc 100644
--- a/internal/llmapp/overview_test.go
+++ b/internal/llmapp/overview_test.go
@@ -9,6 +9,7 @@
 	"strings"
 	"testing"
 
+	"github.com/google/go-cmp/cmp"
 	"golang.org/x/oscar/internal/llm"
 )
 
@@ -17,19 +18,45 @@
 	g := llm.EchoTextGenerator()
 	d1 := &Doc{URL: "https://example.com", Author: "rsc", Title: "title", Text: "some text"}
 	d2 := &Doc{Text: "some text 2"}
-	got, err := Overview(ctx, g, Documents, d1, d2)
+	got, err := Overview(ctx, g, d1, d2)
 	if err != nil {
 		t.Fatal(err)
 	}
-	prompt := Documents.instructions()
-	want := llm.EchoResponse(
+	promptParts := []string{
 		`{"url":"https://example.com","author":"rsc","title":"title","text":"some text"}`,
 		`{"text":"some text 2"}`,
-		prompt)
-	if got != want {
-		t.Errorf("Overview() = %s, want %s", got, want)
+		documents.instructions(),
 	}
-	t.Log(want)
+	want := &OverviewResult{
+		Overview: llm.EchoResponse(promptParts...),
+		Prompt:   promptParts,
+	}
+	if diff := cmp.Diff(got, want); diff != "" {
+		t.Errorf("Overview() mismatch (-got +want):\n%s", diff)
+	}
+}
+
+func TestPostOverview(t *testing.T) {
+	ctx := context.Background()
+	g := llm.EchoTextGenerator()
+	d1 := &Doc{URL: "https://example.com", Author: "rsc", Title: "title", Text: "some text"}
+	d2 := &Doc{Text: "some text 2"}
+	got, err := PostOverview(ctx, g, d1, []*Doc{d2})
+	if err != nil {
+		t.Fatal(err)
+	}
+	promptParts := []string{
+		`{"url":"https://example.com","author":"rsc","title":"title","text":"some text"}`,
+		`{"text":"some text 2"}`,
+		postAndComments.instructions(),
+	}
+	want := &OverviewResult{
+		Overview: llm.EchoResponse(promptParts...),
+		Prompt:   promptParts,
+	}
+	if diff := cmp.Diff(got, want); diff != "" {
+		t.Errorf("PostOverview() mismatch (-got +want):\n%s", diff)
+	}
 }
 
 func TestInstructions(t *testing.T) {
@@ -37,7 +64,7 @@
 	wantPost := "post"    // only in PostAndComments
 
 	t.Run("Documents", func(t *testing.T) {
-		di := Documents.instructions()
+		di := documents.instructions()
 		if !strings.Contains(di, wantAll) {
 			t.Errorf("Documents.instructions(): does not contain %q", wantAll)
 		}
@@ -47,7 +74,7 @@
 	})
 
 	t.Run("PostAndComments", func(t *testing.T) {
-		pi := PostAndComments.instructions()
+		pi := postAndComments.instructions()
 		if !strings.Contains(pi, wantAll) {
 			t.Fatalf("PostAndComments.instructions(): does not contain %q", wantAll)
 		}