diff --git a/src/clients.ts b/src/clients.ts
index a6a8348..4c036e1 100644
--- a/src/clients.ts
+++ b/src/clients.ts
@@ -1,6 +1,7 @@
 import { Client } from "@notionhq/client";
 import { assertWorkspaceScope, getAccountId, DEFAULT_ACCOUNT_ID } from "./context.js";
 import { getAccountToken, ensureAccountToken, onAccountTokensInvalidated } from "./account-tokens.js";
+import { NOTION_API_VERSION } from "./notion-version.js";
 
 // PAT tokens — used for ALL operations except /v1/search.
 // PATs inherit the creator user's permissions (full read/write by ID) but
@@ -58,9 +59,9 @@ if (bearerToken && bearerToken.length < 32) {
   process.exit(1);
 }
 
-// Notion API version. 2025-09-03 unlocks multi-source databases,
-// data_sources endpoints, comments threading, and file uploads.
-export const NOTION_API_VERSION = "2025-09-03";
+// Notion API version: single source of truth in notion-version.ts. Re-exported
+// here for the many call sites that already import it from clients.ts.
+export { NOTION_API_VERSION };
 
 // PAT clients (default — used everywhere except search).
 export const globalcriptoClient = new Client({
diff --git a/src/notion-oauth.ts b/src/notion-oauth.ts
index 1027365..5d30c34 100644
--- a/src/notion-oauth.ts
+++ b/src/notion-oauth.ts
@@ -13,9 +13,7 @@ import { invalidateAccountTokens } from "./account-tokens.js";
 const AUTHORIZE_URL = "https://api.notion.com/v1/oauth/authorize";
 const TOKEN_URL = "https://api.notion.com/v1/oauth/token";
 const ME_URL = "https://api.notion.com/v1/users/me";
-// Keep in sync with NOTION_API_VERSION in clients.ts (not imported — clients.ts
-// process.exit()s at load when NOTION_*_TOKEN are unset, which breaks unit tests).
-const NOTION_VERSION = "2025-09-03";
+import { NOTION_API_VERSION as NOTION_VERSION } from "./notion-version.js";
 
 /** Stable account id for a connected Notion workspace (P1: account = a Notion
  *  OAuth identity). Prefixed so it never collides with the built-in 'bruno'. */
diff --git a/src/notion-version.ts b/src/notion-version.ts
new file mode 100644
index 0000000..f4ff85e
--- /dev/null
+++ b/src/notion-version.ts
@@ -0,0 +1,8 @@
+// src/notion-version.ts
+// Single source of truth for the pinned Notion API version. Lives in its own
+// side-effect-free module (no env validation, no client construction) so any
+// file can import it WITHOUT pulling clients.ts's import-time env checks — which
+// is exactly why several modules used to redeclare the literal "2025-09-03".
+//
+// 2025-09-03: multi-source databases, file uploads, comments, schema PATCH.
+export const NOTION_API_VERSION = "2025-09-03";
diff --git a/src/portal/task-tracker.ts b/src/portal/task-tracker.ts
index 6d04b18..eab3edf 100644
--- a/src/portal/task-tracker.ts
+++ b/src/portal/task-tracker.ts
@@ -20,8 +20,8 @@ import {
   type Detection,
   type DataSourceLite,
 } from "./task-tracker-schema.js";
+import { NOTION_API_VERSION as NOTION_VERSION } from "../notion-version.js";
 
-const NOTION_VERSION = "2025-09-03"; // manter em sincronia com clients.ts
 const NOTION_API = "https://api.notion.com";
 const TASKS_DB_KIND = "tasks_db";
 // Quantas data sources inspecionar (1 GET de schema cada) na detecção. Bound de
diff --git a/src/rag/search.ts b/src/rag/search.ts
index 0291467..cfd5c74 100644
--- a/src/rag/search.ts
+++ b/src/rag/search.ts
@@ -177,47 +177,6 @@ function maxPerUrlConfig(): number {
   return Number.isFinite(v) ? v : 3;
 }
 
-/**
- * Optional recency boost applied AFTER reranking (or after RRF fallback).
- * Controlled by RECENCY_BOOST env var (default "off" / 0).
- *
- * Formula: final_score = score * (1 + beta * exp(-age_days / halflife))
- *   beta     = RECENCY_BOOST  (e.g. 0.15 → max +15% for today's docs)
- *   halflife = RECENCY_HALFLIFE_DAYS (default 30)
- *   age_days derived from chunk.metadata.data (ISO date string) or source_updated.
- *
- * With RECENCY_BOOST=0 (or unset) returns hits unchanged — zero cost.
- * Positive beta boosts recent content; negative beta penalizes it (unusual).
- */
-export function recencyBoostEnabled(): boolean {
-  const v = Number(process.env.RECENCY_BOOST);
-  return Number.isFinite(v) && v !== 0;
-}
-
-export function applyRecencyBoost(hits: SearchHit[], now: Date = new Date()): SearchHit[] {
-  const beta = Number(process.env.RECENCY_BOOST);
-  if (!Number.isFinite(beta) || beta === 0) return hits;
-  const halflife = Number(process.env.RECENCY_HALFLIFE_DAYS ?? 30);
-  const hl = Number.isFinite(halflife) && halflife > 0 ? halflife : 30;
-  // ln(2)/halflife is the decay constant for exp(-age * lambda)
-  const lambda = Math.LN2 / hl;
-
-  const boosted = hits.map((h) => {
-    const dateStr =
-      (typeof h.chunk.metadata?.data === "string" ? h.chunk.metadata.data : undefined) ??
-      (h.chunk.source_updated instanceof Date ? h.chunk.source_updated.toISOString() : undefined);
-    if (!dateStr) return h;
-    const docDate = new Date(dateStr);
-    if (isNaN(docDate.getTime())) return h;
-    const ageDays = Math.max(0, (now.getTime() - docDate.getTime()) / 86_400_000);
-    const boost = 1 + beta * Math.exp(-ageDays * lambda);
-    return { ...h, score: h.score * boost };
-  });
-
-  // Re-sort by boosted score (recency may reorder).
-  return boosted.sort((a, b) => b.score - a.score);
-}
-
 /**
  * Query-time result diversification. Iterates `hits` in their given (already
  * ranked) order and KEEPS a hit unless:
@@ -426,11 +385,6 @@ export async function brainSearch(
     }
   }
 
-  // Optional recency boost (RECENCY_BOOST env, default off). Applied after all
-  // ranking/diversification so it can only reorder within the already-diversified
-  // topK set, not expand it. Zero cost when RECENCY_BOOST=0 or unset.
-  hits = applyRecencyBoost(hits);
-
   // 002-app-v2 — AI search transparency log. Companion to the recordUsage
   // metering above, but appended AFTER the hits are computed so the row carries
   // the real result count. Only in-request searches are logged (cron/eval have
diff --git a/src/tasks/adapter.ts b/src/tasks/adapter.ts
index 3054ce6..684a837 100644
--- a/src/tasks/adapter.ts
+++ b/src/tasks/adapter.ts
@@ -25,9 +25,9 @@ import {
   type CanonicalPriority,
   type CanonicalField,
 } from "./model.js";
+import { NOTION_API_VERSION as NOTION_VERSION } from "../notion-version.js";
 
 const NOTION_API = "https://api.notion.com";
-const NOTION_VERSION = "2025-09-03"; // keep in sync with clients.ts
 
 /** The owner's Tasks Tracker data_source (workspace 'personal') — formerly
  *  hardcoded in briefing/daily-briefing.ts:31. Now ONLY a safety net used when