diff --git a/CAPABILITY-MAP.md b/CAPABILITY-MAP.md
index 3f7442b..89735b8 100644
--- a/CAPABILITY-MAP.md
+++ b/CAPABILITY-MAP.md
@@ -31,8 +31,8 @@ Build sequence: data foundation → identity and analytics → API → dashboard
 
 ## Dataset facts that constrain the design
 
-- Source grain: one payment attempt, uniquely identified by `(session_key, try_seq)`.
-- Observed volume: 2,213,289 attempts, 2,062,839 sessions, 343 merchants, 348 terminals, 5 categories.
+- Source grain: one attempt-or-no-attempt session record, uniquely identified by `(session_key, try_seq)`. A `try_seq = 0`/`NoAttempt` marker creates no normalized attempt.
+- Observed volume: 2,213,289 source records, including 263,936 no-attempt markers and 1,949,353 actual attempts; 2,062,839 sessions, 343 merchants, 348 terminals, and 5 categories.
 - Observed period: 2026-01-01 through 2026-07-01.
 - Nullability is material: response, PSP, issuer/card, verification timing, and settlement fields are incomplete.
 - Source `adjusted_fee` is the merchant-fee field for this product and is normalized once per session as a real Rial amount; the challenge source name/value was confidentiality-adjusted.