diff --git a/bot/src/security/initdata.ts b/bot/src/security/initdata.ts
index de2efc1..b01b750 100644
--- a/bot/src/security/initdata.ts
+++ b/bot/src/security/initdata.ts
@@ -56,15 +56,6 @@ export interface WebAppInitChat {
   photo_url?: string;
 }
 
-/** Shape of a fully parsed initData payload (hash/signature excluded from
- *  rawFields — they are auth metadata, not payload fields). */
-export interface ParsedInitData {
-  user: WebAppInitUser;
-  chat?: WebAppInitChat;
-  authDate: number;
-  rawFields: Map<string, string>;
-}
-
 export interface ValidateInitDataOptions {
   /** "Now" in seconds-since-epoch — injectable for deterministic tests. */
   nowSeconds?: number;
@@ -95,8 +86,9 @@ function parseFields(raw: string): Map<string, string> {
     try {
       fields.set(key, decodeURIComponent(value));
     } catch {
-      // Undecodable percent-escape — keep raw so HMAC compare fails ("tampered")
-      // rather than silently dropping the field.
+      // Intent: an undecodable percent-escape keeps the RAW value so the HMAC
+      // compare fails ("tampered") rather than silently dropping the field —
+      // malformed-vs-tampered precedence (D-14).
       fields.set(key, value);
     }
   }
@@ -160,6 +152,8 @@ export async function validateInitData(
         user = parsed as WebAppInitUser;
       }
     } catch {
+      // Intent: a malformed user payload is the "malformed" class, not a
+      // tampered one — the field never reaches the HMAC path.
       user = undefined;
     }
   }
@@ -209,6 +203,8 @@ export async function validateInitData(
         chat = parsedChat as WebAppInitChat;
       }
     } catch {
+      // Intent: a malformed chat payload degrades to "no chat context" (a
+      // private chat) — it never fails an otherwise-valid private-chat payload.
       chat = undefined;
     }
   }
diff --git a/bot/test/initdata.test.mjs b/bot/test/initdata.test.mjs
index 728022c..4536b6a 100644
--- a/bot/test/initdata.test.mjs
+++ b/bot/test/initdata.test.mjs
@@ -188,6 +188,14 @@ test("T4 freshness boundary: age 901 s → reason stale", async () => {
   assert.equal(res.reason, "stale");
 });
 
+test("T4 freshness boundary: age 900 s → ok:true (the boundary is INCLUSIVE)", async () => {
+  const validateInitData = await loadValidator();
+  const now = Math.floor(Date.now() / 1000);
+  const raw = signedUser(now - 900);
+  const res = await validateInitData(raw, TEST_TOKEN);
+  assert.equal(res.ok, true, `expected ok:true at exactly 900 s, got ${JSON.stringify(res)}`);
+});
+
 /* ————— T5 — field order independence (RESEARCH Pitfall 1) ————— */
 
 test("T5 fields arriving out of alphabetical order still validate", async () => {
diff --git a/bot/wrangler.jsonc b/bot/wrangler.jsonc
index 00c7f76..3737bcd 100644
--- a/bot/wrangler.jsonc
+++ b/bot/wrangler.jsonc
@@ -1,5 +1,5 @@
 {
-  // KV namespace id is filled in plan 03 task 1 after `npx wrangler kv namespace create chat_sessions`
+  // chat_sessions namespace created via `npx wrangler kv namespace create chat_sessions` — the id below is live.
   "name": "araharah-bot",
   "main": "src/webhook.ts",
   "compatibility_date": "2026-10-22",