diff --git a/src/app/admin/leads/actions.ts b/src/app/admin/leads/actions.ts
index f9edfd5..03239f8 100644
--- a/src/app/admin/leads/actions.ts
+++ b/src/app/admin/leads/actions.ts
@@ -2,7 +2,8 @@
 
 import { z } from "zod";
 import { db } from "@/db";
-import { leads, quotes, tags } from "@/db/schema";
+import { leads, quotes, tags, clientTranscripts } from "@/db/schema";
+import { nanoid } from "nanoid";
 import { eq, and } from "drizzle-orm";
 import {
   createLeadSchema,
@@ -252,3 +253,58 @@ export async function renameLeadTag(oldValue: string, newValue: string) {
 
   revalidatePath("/admin/leads");
 }
+
+// ── Transcript actions (Phase 20 — KB-02) ────────────────────────────────────
+
+const addTranscriptSchema = z.object({
+  lead_id: z.string().min(1),
+  title: z.string().optional(),
+  content: z.string().min(1, "Il testo del transcript è obbligatorio"),
+  call_date: z.string().regex(/^\d{4}-\d{2}-\d{2}$/, "Data non valida (YYYY-MM-DD)"),
+});
+
+export async function addTranscript(data: z.infer<typeof addTranscriptSchema>) {
+  await requireAdmin();
+
+  const parsed = addTranscriptSchema.safeParse(data);
+  if (!parsed.success) {
+    return { success: false, error: parsed.error.issues[0].message };
+  }
+
+  try {
+    const [transcript] = await db
+      .insert(clientTranscripts)
+      .values({
+        id: nanoid(),
+        lead_id: parsed.data.lead_id,
+        title: parsed.data.title || null,
+        content: parsed.data.content,
+        call_date: parsed.data.call_date,
+      })
+      .returning();
+
+    revalidatePath(`/admin/leads/${parsed.data.lead_id}`);
+    return { success: true, transcript };
+  } catch (error) {
+    console.error("addTranscript error:", error);
+    return { success: false, error: "Errore nel salvataggio del transcript" };
+  }
+}
+
+export async function deleteTranscript(transcriptId: string, leadId: string) {
+  await requireAdmin();
+
+  if (!transcriptId) throw new Error("ID transcript richiesto");
+
+  try {
+    await db
+      .delete(clientTranscripts)
+      .where(eq(clientTranscripts.id, transcriptId));
+
+    revalidatePath(`/admin/leads/${leadId}`);
+    return { success: true };
+  } catch (error) {
+    console.error("deleteTranscript error:", error);
+    return { success: false, error: "Errore nell'eliminazione del transcript" };
+  }
+}
diff --git a/src/db/schema.ts b/src/db/schema.ts
index 5079418..3ba13aa 100644
--- a/src/db/schema.ts
+++ b/src/db/schema.ts
@@ -498,10 +498,31 @@ export const reminders = pgTable("reminders", {
     .defaultNow(),
 });
 
+// ============ CLIENT TRANSCRIPTS TABLE (Knowledge Base — Phase 20) ============
+// Transcript datati delle call, multipli per lead o cliente.
+// lead_id e client_id sono entrambi nullable (D-01): un transcript può appartenere
+// a un lead pre-conversione (Phase 20 UI) o a un cliente post-conversione (futuro).
+export const clientTranscripts = pgTable("client_transcripts", {
+  id: text("id")
+    .primaryKey()
+    .$defaultFn(() => nanoid()),
+  lead_id: text("lead_id")
+    .references(() => leads.id, { onDelete: "cascade" }),
+  client_id: text("client_id")
+    .references(() => clients.id, { onDelete: "cascade" }),
+  title: text("title"),
+  content: text("content").notNull(),
+  call_date: text("call_date").notNull(), // "YYYY-MM-DD" — coerente con <input type="date">
+  created_at: timestamp("created_at", { withTimezone: true })
+    .notNull()
+    .defaultNow(),
+});
+
 // ============ RELATIONS ============
 
 export const clientsRelations = relations(clients, ({ many }) => ({
   projects: many(projects),
+  transcripts: many(clientTranscripts),
 }));
 
 export const projectsRelations = relations(projects, ({ one, many }) => ({
@@ -632,6 +653,7 @@ export const leadsRelations = relations(leads, ({ many }) => ({
   quotes: many(quotes),
   activities: many(activities),
   reminders: many(reminders),
+  transcripts: many(clientTranscripts),
 }));
 
 export const activitiesRelations = relations(activities, ({ one }) => ({
@@ -642,6 +664,17 @@ export const remindersRelations = relations(reminders, ({ one }) => ({
   lead: one(leads, { fields: [reminders.lead_id], references: [leads.id] }),
 }));
 
+export const clientTranscriptsRelations = relations(clientTranscripts, ({ one }) => ({
+  lead: one(leads, {
+    fields: [clientTranscripts.lead_id],
+    references: [leads.id],
+  }),
+  client: one(clients, {
+    fields: [clientTranscripts.client_id],
+    references: [clients.id],
+  }),
+}));
+
 export const quotesRelations = relations(quotes, ({ one, many }) => ({
   lead: one(leads, { fields: [quotes.lead_id], references: [leads.id] }),
   client: one(clients, { fields: [quotes.client_id], references: [clients.id] }),
@@ -704,4 +737,6 @@ export type NewLead = typeof leads.$inferInsert;
 export type Activity = typeof activities.$inferSelect;
 export type NewActivity = typeof activities.$inferInsert;
 export type Reminder = typeof reminders.$inferSelect;
-export type NewReminder = typeof reminders.$inferInsert;
\ No newline at end of file
+export type NewReminder = typeof reminders.$inferInsert;
+export type ClientTranscript = typeof clientTranscripts.$inferSelect;
+export type NewClientTranscript = typeof clientTranscripts.$inferInsert;
\ No newline at end of file
diff --git a/src/lib/lead-service.ts b/src/lib/lead-service.ts
index d436229..ca312ad 100644
--- a/src/lib/lead-service.ts
+++ b/src/lib/lead-service.ts
@@ -1,6 +1,6 @@
 import { eq, and, isNull, desc, gte, lte, ilike, or } from "drizzle-orm";
 import { db } from "@/db";
-import { leads, activities, reminders, quotes } from "@/db/schema";
+import { leads, activities, reminders, quotes, clientTranscripts } from "@/db/schema";
 
 // Get all leads
 export async function getAllLeads(limit: number = 100, offset: number = 0) {
@@ -209,3 +209,13 @@ export async function getQuotesByLeadId(leadId: string) {
     .where(eq(quotes.lead_id, leadId))
     .orderBy(desc(quotes.created_at));
 }
+
+// Get transcript log for a lead — call_date DESC (D-05)
+// Returns all fields including full content (Phase 21 reads them in bulk).
+export async function getTranscripts(leadId: string) {
+  return await db
+    .select()
+    .from(clientTranscripts)
+    .where(eq(clientTranscripts.lead_id, leadId))
+    .orderBy(desc(clientTranscripts.call_date));
+}