Add markdown event descriptions for hosts to provide context

Hosts can now add a free-form description (with markdown rendering via
goldmark) when creating or editing events. Descriptions render safely
with no raw HTML passthrough. Includes ALTER TABLE migration for
existing databases.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

db/models.go

@@ -24,6 +24,7 @@ type Event struct {
 	Time        string
 	Location    string
 	AdminToken  string
+	Description string
 	CreatedAt   time.Time
 }
 

db/queries.sql

@@ -5,10 +5,13 @@ SELECT * FROM events WHERE slug = ?;
 SELECT * FROM events WHERE admin_token = ?;
 
 -- name: CreateEvent :one
-INSERT INTO events (slug, title, date, time, location, admin_token)
+INSERT INTO events (slug, title, date, time, location, admin_token, description)
-VALUES (?, ?, ?, ?, ?, ?)
+VALUES (?, ?, ?, ?, ?, ?, ?)
 RETURNING *;
 
+-- name: UpdateEventDescription :exec
+UPDATE events SET description = ? WHERE id = ?;
+
 -- name: UpdateEvent :exec
 UPDATE events SET title = ?, date = ?, time = ?, location = ? WHERE id = ?;
 

db/queries.sql.go

@@ -57,9 +57,9 @@ func (q *Queries) CreateClaim(ctx context.Context, arg CreateClaimParams) (Claim
 }
 
 const createEvent = `-- name: CreateEvent :one
-INSERT INTO events (slug, title, date, time, location, admin_token)
+INSERT INTO events (slug, title, date, time, location, admin_token, description)
-VALUES (?, ?, ?, ?, ?, ?)
+VALUES (?, ?, ?, ?, ?, ?, ?)
-RETURNING id, slug, title, date, time, location, admin_token, created_at
+RETURNING id, slug, title, date, time, location, admin_token, description, created_at
 `
 
 type CreateEventParams struct {
@@ -69,6 +69,7 @@ type CreateEventParams struct {
 	Time        string
 	Location    string
 	AdminToken  string
+	Description string
 }
 
 func (q *Queries) CreateEvent(ctx context.Context, arg CreateEventParams) (Event, error) {
@@ -79,6 +80,7 @@ func (q *Queries) CreateEvent(ctx context.Context, arg CreateEventParams) (Event
 		arg.Time,
 		arg.Location,
 		arg.AdminToken,
+		arg.Description,
 	)
 	var i Event
 	err := row.Scan(
@@ -89,6 +91,7 @@ func (q *Queries) CreateEvent(ctx context.Context, arg CreateEventParams) (Event
 		&i.Time,
 		&i.Location,
 		&i.AdminToken,
+		&i.Description,
 		&i.CreatedAt,
 	)
 	return i, err
@@ -190,7 +193,7 @@ func (q *Queries) DeleteSlot(ctx context.Context, id int64) error {
 }
 
 const getEventByAdminToken = `-- name: GetEventByAdminToken :one
-SELECT id, slug, title, date, time, location, admin_token, created_at FROM events WHERE admin_token = ?
+SELECT id, slug, title, date, time, location, admin_token, description, created_at FROM events WHERE admin_token = ?
 `
 
 func (q *Queries) GetEventByAdminToken(ctx context.Context, adminToken string) (Event, error) {
@@ -204,13 +207,14 @@ func (q *Queries) GetEventByAdminToken(ctx context.Context, adminToken string) (
 		&i.Time,
 		&i.Location,
 		&i.AdminToken,
+		&i.Description,
 		&i.CreatedAt,
 	)
 	return i, err
 }
 
 const getEventBySlug = `-- name: GetEventBySlug :one
-SELECT id, slug, title, date, time, location, admin_token, created_at FROM events WHERE slug = ?
+SELECT id, slug, title, date, time, location, admin_token, description, created_at FROM events WHERE slug = ?
 `
 
 func (q *Queries) GetEventBySlug(ctx context.Context, slug string) (Event, error) {
@@ -224,6 +228,7 @@ func (q *Queries) GetEventBySlug(ctx context.Context, slug string) (Event, error
 		&i.Time,
 		&i.Location,
 		&i.AdminToken,
+		&i.Description,
 		&i.CreatedAt,
 	)
 	return i, err
@@ -406,6 +411,20 @@ func (q *Queries) UpdateEvent(ctx context.Context, arg UpdateEventParams) error
 	return err
 }
 
+const updateEventDescription = `-- name: UpdateEventDescription :exec
+UPDATE events SET description = ? WHERE id = ?
+`
+
+type UpdateEventDescriptionParams struct {
+	Description string
+	ID          int64
+}
+
+func (q *Queries) UpdateEventDescription(ctx context.Context, arg UpdateEventDescriptionParams) error {
+	_, err := q.db.ExecContext(ctx, updateEventDescription, arg.Description, arg.ID)
+	return err
+}
+
 const updateSlot = `-- name: UpdateSlot :exec
 UPDATE slots SET name = ?, emoji = ?, max_claims = ? WHERE id = ?
 `

go.mod

@@ -5,4 +5,5 @@ go 1.22
 require (
 	github.com/go-chi/chi/v5 v5.2.5 // indirect
 	github.com/mattn/go-sqlite3 v1.14.44 // indirect
+	github.com/yuin/goldmark v1.8.2 // indirect
 )

go.sum

@@ -2,3 +2,5 @@ github.com/go-chi/chi/v5 v5.2.5 h1:Eg4myHZBjyvJmAFjFvWgrqDTXFyOzjj7YIm3L3mu6Ug=
 github.com/go-chi/chi/v5 v5.2.5/go.mod h1:X7Gx4mteadT3eDOMTsXzmI4/rwUpOwBHLpAfupzFJP0=
 github.com/mattn/go-sqlite3 v1.14.44 h1:3VSe+xafpbzsLbdr2AWlAZk9yRHiBhTBakioXaCKTF8=
 github.com/mattn/go-sqlite3 v1.14.44/go.mod h1:pjEuOr8IwzLJP2MfGeTb0A35jauH+C2kbHKBr7yXKVQ=
+github.com/yuin/goldmark v1.8.2 h1:kEGpgqJXdgbkhcOgBxkC0X0PmoPG1ZyoZ117rDVp4zE=
+github.com/yuin/goldmark v1.8.2/go.mod h1:ip/1k0VRfGynBgxOz0yCqHrbZXhcjxyuS66Brc7iBKg=

handlers.go

@@ -6,6 +6,7 @@ import (
 	"database/sql"
 	"encoding/hex"
 	"fmt"
+	"html/template"
 	"log"
 	"net/http"
 	"strconv"
@@ -17,6 +18,7 @@ import (
 
 const (
 	maxFieldLen  = 200
+	maxDescLen   = 5000
 	maxNoteLen   = 500
 	maxSlots     = 20
 	maxRsvps     = 200
@@ -57,6 +59,7 @@ func (s *Server) handleCreateEvent(w http.ResponseWriter, r *http.Request) {
 	date := sanitize(r.FormValue("date"), maxFieldLen)
 	time_ := sanitize(r.FormValue("time"), maxFieldLen)
 	location := sanitize(r.FormValue("location"), maxFieldLen)
+	description := sanitize(r.FormValue("description"), maxDescLen)
 
 	if title == "" {
 		http.Error(w, "Title is required", http.StatusBadRequest)
@@ -66,7 +69,7 @@ func (s *Server) handleCreateEvent(w http.ResponseWriter, r *http.Request) {
 	slug := randomSlug()
 	token := randomToken()
 	event, err := s.q.CreateEvent(r.Context(), db.CreateEventParams{
-		Slug: slug, Title: title, Date: date, Time: time_, Location: location, AdminToken: token,
+		Slug: slug, Title: title, Date: date, Time: time_, Location: location, AdminToken: token, Description: description,
 	})
 	if err != nil {
 		log.Printf("create event: %v", err)
@@ -125,6 +128,7 @@ type EventPageData struct {
 	TotalGoing      int64
 	IsAdmin         bool
 	BaseURL         string
+	DescriptionHTML template.HTML
 }
 
 func (s *Server) loadEventPage(r *http.Request, slug string, isAdmin bool) (*EventPageData, error) {
@@ -176,6 +180,11 @@ func (s *Server) loadEventPage(r *http.Request, slug string, isAdmin bool) (*Eve
 	}
 	totalGoing += int64(len(rsvps))
 
+	var descHTML template.HTML
+	if event.Description != "" {
+		descHTML = RenderMarkdown(event.Description)
+	}
+
 	return &EventPageData{
 		Event:           event,
 		Slots:           slotViews,
@@ -183,6 +192,7 @@ func (s *Server) loadEventPage(r *http.Request, slug string, isAdmin bool) (*Eve
 		TotalGoing:      totalGoing,
 		IsAdmin:         isAdmin,
 		BaseURL:         s.baseURL,
+		DescriptionHTML: descHTML,
 	}, nil
 }
 
@@ -425,6 +435,28 @@ func (s *Server) handleAdmin(w http.ResponseWriter, r *http.Request) {
 	pageTmpl["event"].ExecuteTemplate(w, "layout", data)
 }
 
+func (s *Server) handleUpdateDescription(w http.ResponseWriter, r *http.Request) {
+	slug := chi.URLParam(r, "slug")
+	token := chi.URLParam(r, "token")
+
+	event, err := s.q.GetEventBySlug(r.Context(), slug)
+	if err != nil || event.AdminToken != token {
+		http.NotFound(w, r)
+		return
+	}
+
+	r.Body = http.MaxBytesReader(w, r.Body, 32*1024)
+	r.ParseForm()
+	description := sanitize(r.FormValue("description"), maxDescLen)
+
+	s.q.UpdateEventDescription(r.Context(), db.UpdateEventDescriptionParams{
+		Description: description,
+		ID:          event.ID,
+	})
+
+	http.Redirect(w, r, fmt.Sprintf("/e/%s/admin/%s", slug, token), http.StatusSeeOther)
+}
+
 func (s *Server) handleCreateSlot(w http.ResponseWriter, r *http.Request) {
 	slug := chi.URLParam(r, "slug")
 	token := chi.URLParam(r, "token")

main.go

@@ -104,6 +104,7 @@ func main() {
 	if _, err := database.Exec(schemaSQL); err != nil {
 		log.Fatal("schema init: ", err)
 	}
+	runMigrations(database)
 
 	funcMap := template.FuncMap{
 		"pct": func(count, max int64) int64 {
@@ -160,6 +161,7 @@ func main() {
 
 	// Admin
 	r.Get("/e/{slug}/admin/{token}", srv.handleAdmin)
+	r.Post("/e/{slug}/admin/{token}/description", srv.handleUpdateDescription)
 	r.Post("/e/{slug}/admin/{token}/slot", srv.handleCreateSlot)
 	r.Delete("/e/{slug}/admin/{token}/slot/{slotID}", srv.handleDeleteSlot)
 

markdown.go

@@ -0,0 +1,23 @@
+package main
+
+import (
+	"bytes"
+	"html/template"
+
+	"github.com/yuin/goldmark"
+	"github.com/yuin/goldmark/renderer/html"
+)
+
+var mdRenderer = goldmark.New(
+	goldmark.WithRendererOptions(
+		html.WithHardWraps(),
+	),
+)
+
+func RenderMarkdown(input string) template.HTML {
+	var buf bytes.Buffer
+	if err := mdRenderer.Convert([]byte(input), &buf); err != nil {
+		return template.HTML(template.HTMLEscapeString(input))
+	}
+	return template.HTML(buf.String())
+}

migrate.go

@@ -0,0 +1,17 @@
+package main
+
+import (
+	"database/sql"
+	"log"
+	"strings"
+)
+
+func runMigrations(database *sql.DB) {
+	_, err := database.Exec(`ALTER TABLE events ADD COLUMN description TEXT DEFAULT ''`)
+	if err != nil {
+		if strings.Contains(err.Error(), "duplicate column name") {
+			return
+		}
+		log.Printf("migration warning: %v", err)
+	}
+}

schema.sql

@@ -6,6 +6,7 @@ CREATE TABLE IF NOT EXISTS events (
     time       TEXT    NOT NULL,       -- e.g. "2:00 PM"
     location   TEXT    NOT NULL,
     admin_token TEXT   NOT NULL UNIQUE,
+    description TEXT    NOT NULL DEFAULT '',
     created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
 );
 

templates/event.html

@@ -26,6 +26,9 @@
     {{if .Event.Time}}<span>&#128338; {{.Event.Time}}</span>{{end}}
     {{if .Event.Location}}<span>&#128205; {{.Event.Location}}</span>{{end}}
   </div>
+  {{if .DescriptionHTML}}
+  <div class="event-description">{{.DescriptionHTML}}</div>
+  {{end}}
 </div>
 
 <div id="slots-container"
@@ -87,6 +90,17 @@
 {{end}}
 
 {{if .IsAdmin}}
+<div class="section-label" style="margin-top:40px">Admin: Description</div>
+<div class="claim-form-wrapper">
+  <form method="POST" action="/e/{{.Event.Slug}}/admin/{{.Event.AdminToken}}/description">
+    <div class="form-row">
+      <label>Event description (markdown supported)</label>
+      <textarea name="description" rows="5" style="border:var(--border-w) solid var(--border);background:var(--cream);padding:10px 14px;font-family:'Bricolage Grotesque',sans-serif;font-size:0.95rem;resize:vertical;outline:none;">{{.Event.Description}}</textarea>
+    </div>
+    <button class="btn-submit" type="submit">Save description</button>
+  </form>
+</div>
+
 <div class="section-label" style="margin-top:40px">Admin: Add slot</div>
 <div class="claim-form-wrapper">
   <form hx-post="/e/{{.Event.Slug}}/admin/{{.Event.AdminToken}}/slot"

templates/home.html

@@ -29,6 +29,10 @@
       <label>Location</label>
       <input type="text" name="location" placeholder="e.g. Long Meadow, entrance at 9th St">
     </div>
+    <div class="form-row">
+      <label>Description (optional, markdown supported)</label>
+      <textarea name="description" rows="4" placeholder="e.g. Bring your own blanket! We'll have a grill set up near the big oak tree." style="border:var(--border-w) solid var(--border);background:var(--cream);padding:10px 14px;font-family:'Bricolage Grotesque',sans-serif;font-size:0.95rem;resize:vertical;outline:none;"></textarea>
+    </div>
 
     <div class="section-label" style="margin:24px 0 16px">Slots</div>
 

templates/layout.html

@@ -97,6 +97,41 @@
     font-size: 0.78rem;
     color: #555;
   }
+  .event-description {
+    margin-top: 16px;
+    padding-top: 16px;
+    border-top: 1px solid #ddd;
+    font-size: 0.92rem;
+    line-height: 1.6;
+  }
+  .event-description h1 { font-size: 1.3rem; margin: 16px 0 8px; }
+  .event-description h2 { font-size: 1.15rem; margin: 14px 0 6px; }
+  .event-description h3 { font-size: 1.05rem; margin: 12px 0 4px; }
+  .event-description p { margin: 8px 0; }
+  .event-description ul, .event-description ol { margin: 8px 0; padding-left: 24px; }
+  .event-description li { margin: 4px 0; }
+  .event-description a { color: var(--ink); text-decoration: underline; }
+  .event-description code {
+    font-family: 'DM Mono', monospace;
+    background: var(--cream);
+    padding: 2px 6px;
+    font-size: 0.85em;
+    border: 1px solid #ddd;
+  }
+  .event-description pre {
+    background: var(--cream);
+    border: 1px solid #ddd;
+    padding: 12px;
+    overflow-x: auto;
+    margin: 8px 0;
+  }
+  .event-description pre code { background: none; border: none; padding: 0; }
+  .event-description blockquote {
+    border-left: 3px solid var(--ink);
+    padding-left: 12px;
+    margin: 8px 0;
+    color: #555;
+  }
   .section-label {
     font-family: 'DM Mono', monospace;
     font-size: 0.7rem;
@@ -230,7 +265,7 @@
     transition: box-shadow 0.1s;
     appearance: none;
   }
-  .form-row input:focus, .form-row select:focus {
+  .form-row input:focus, .form-row select:focus, .form-row textarea:focus {
     box-shadow: 3px 3px 0 var(--ink);
   }
   .btn-submit {