diff --git a/packages/gittensory-miner/lib/claim-ledger.js b/packages/gittensory-miner/lib/claim-ledger.js
index 74493a0f39..5cfc96fcb4 100644
--- a/packages/gittensory-miner/lib/claim-ledger.js
+++ b/packages/gittensory-miner/lib/claim-ledger.js
@@ -1,4 +1,5 @@
 import { normalizeLocalStoreDbPath, openLocalStoreDb, resolveLocalStoreDbPath } from "./local-store.js";
+import { applySchemaMigrations } from "./schema-version.js";
 
 // The miner's local soft-claim ledger (#2314): a 100% client-side record of "I'm working on issue #N in repo X",
 // so Phase 2's soft-claim adjudication (sibling issues) has somewhere to persist claims. Schema + CRUD only — no
@@ -71,6 +72,8 @@ export function openClaimLedger(dbPath = resolveClaimLedgerDbPath()) {
       UNIQUE (repo_full_name, issue_number)
     )
   `);
+  // Schema-version convention (#4832): stamp the baseline and run any post-baseline migrations (none yet).
+  applySchemaMigrations(db, []);
 
   // Idempotent claim in ONE atomic statement: insert a new active claim, or — only if the existing row is NOT
   // already active — re-activate it (a released/expired claim can be re-claimed). The `WHERE status <> 'active'`
diff --git a/packages/gittensory-miner/lib/event-ledger.js b/packages/gittensory-miner/lib/event-ledger.js
index 2794fcf527..09c0585f60 100644
--- a/packages/gittensory-miner/lib/event-ledger.js
+++ b/packages/gittensory-miner/lib/event-ledger.js
@@ -1,5 +1,6 @@
 import { isDeepStrictEqual } from "node:util";
 import { normalizeLocalStoreDbPath, openLocalStoreDb, resolveLocalStoreDbPath } from "./local-store.js";
+import { applySchemaMigrations } from "./schema-version.js";
 
 // The miner's local, append-only event ledger (#2290): an immutable audit trail of every significant miner-loop
 // event (discovered_issue, plan_built, plan_step_completed, pr_prepared, … — a small fixed vocabulary for this
@@ -103,6 +104,8 @@ export function initEventLedger(dbPath = resolveEventLedgerDbPath()) {
       created_at TEXT NOT NULL
     )
   `);
+  // Schema-version convention (#4832): stamp the baseline and run any post-baseline migrations (none yet).
+  applySchemaMigrations(db, []);
 
   const nextSeqStatement = db.prepare("SELECT COALESCE(MAX(seq), 0) + 1 AS nextSeq FROM miner_event_ledger");
   const appendStatement = db.prepare(`
diff --git a/packages/gittensory-miner/lib/governor-ledger.js b/packages/gittensory-miner/lib/governor-ledger.js
index 4c52c49742..0c39c47080 100644
--- a/packages/gittensory-miner/lib/governor-ledger.js
+++ b/packages/gittensory-miner/lib/governor-ledger.js
@@ -3,6 +3,7 @@ import { homedir } from "node:os";
 import { dirname, join } from "node:path";
 import { DatabaseSync } from "node:sqlite";
 import { normalizeGovernorLedgerEvent } from "@jsonbored/gittensory-engine";
+import { applySchemaMigrations } from "./schema-version.js";
 
 // Append-only governor decision ledger (#2328): every allowed/denied/throttled/kill-switch outcome lands in a
 // local SQLite table for contributor audit. IMMUTABILITY INVARIANT: INSERT + SELECT only — never UPDATE/DELETE.
@@ -87,6 +88,8 @@ export function initGovernorLedger(dbPath = resolveGovernorLedgerDbPath()) {
     )
   `);
   db.exec("CREATE INDEX IF NOT EXISTS idx_governor_events_repo ON governor_events (repo_full_name, id)");
+  // Schema-version convention (#4832): stamp the baseline and run any post-baseline migrations (none yet).
+  applySchemaMigrations(db, []);
 
   const appendStatement = db.prepare(`
     INSERT INTO governor_events (ts, event_type, repo_full_name, action_class, decision, reason, payload_json)
diff --git a/packages/gittensory-miner/lib/laptop-init.js b/packages/gittensory-miner/lib/laptop-init.js
index b9c47bc557..85c625a315 100644
--- a/packages/gittensory-miner/lib/laptop-init.js
+++ b/packages/gittensory-miner/lib/laptop-init.js
@@ -2,6 +2,7 @@ import { accessSync, chmodSync, constants, existsSync, mkdirSync } from "node:fs
 import { homedir } from "node:os";
 import { delimiter, join } from "node:path";
 import { DatabaseSync } from "node:sqlite";
+import { applySchemaMigrations } from "./schema-version.js";
 
 const defaultDbFileName = "laptop-state.sqlite3";
 
@@ -36,6 +37,8 @@ export function initLaptopState(env = process.env) {
       value TEXT NOT NULL
     )
   `);
+  // Schema-version convention (#4832): stamp the baseline and run any post-baseline migrations (none yet).
+  applySchemaMigrations(db, []);
   if (created) {
     db.prepare("INSERT INTO laptop_meta (key, value) VALUES ('initialized_at', ?)")
       .run(new Date().toISOString());
diff --git a/packages/gittensory-miner/lib/plan-store.js b/packages/gittensory-miner/lib/plan-store.js
index fbd27591b3..251c3781b6 100644
--- a/packages/gittensory-miner/lib/plan-store.js
+++ b/packages/gittensory-miner/lib/plan-store.js
@@ -2,6 +2,7 @@ import { chmodSync, mkdirSync } from "node:fs";
 import { homedir } from "node:os";
 import { dirname, join } from "node:path";
 import { DatabaseSync } from "node:sqlite";
+import { applySchemaMigrations } from "./schema-version.js";
 
 // Local SQLite persistence for the stateless MCP plan DAG (#2318). `gittensory_build_plan`/`plan_status`/
 // `record_step_result` are stateless — the caller holds the plan and passes it back each call — so a miner running
@@ -164,6 +165,8 @@ export function openPlanStore(dbPath = resolvePlanStoreDbPath()) {
       updated_at TEXT NOT NULL
     )
   `);
+  // Schema-version convention (#4832): stamp the baseline and run any post-baseline migrations (none yet).
+  applySchemaMigrations(db, []);
 
   const saveStatement = db.prepare(`
     INSERT INTO miner_plans (plan_id, plan_json, status, updated_at)
diff --git a/packages/gittensory-miner/lib/portfolio-queue.js b/packages/gittensory-miner/lib/portfolio-queue.js
index 923e9a3382..31f993c58e 100644
--- a/packages/gittensory-miner/lib/portfolio-queue.js
+++ b/packages/gittensory-miner/lib/portfolio-queue.js
@@ -1,4 +1,5 @@
 import { normalizeLocalStoreDbPath, openLocalStoreDb, resolveLocalStoreDbPath } from "./local-store.js";
+import { applySchemaMigrations } from "./schema-version.js";
 
 // The miner's local portfolio/queue store (#2292): a 100% client-side, prioritized backlog of candidate work
 // items across every repo the miner has been pointed at ("what should I look at next, across everything I'm
@@ -88,12 +89,18 @@ export function initPortfolioQueueStore(dbPath = resolvePortfolioQueueDbPath())
   // swept back to 'queued' by age (see portfolio-queue-expiry.js) instead of stranding the item forever — the same
   // recovery the claim-ledger and worktree-allocator stores already provide for their own tables (#4827). Additive
   // migration for stores created before this column: CREATE TABLE IF NOT EXISTS never adds a column to a pre-existing
-  // table, so add it idempotently.
-  const hasLeasedAtColumn = db
-    .prepare("PRAGMA table_info(miner_portfolio_queue)")
-    .all()
-    .some((column) => column.name === "leased_at");
-  if (!hasLeasedAtColumn) db.exec("ALTER TABLE miner_portfolio_queue ADD COLUMN leased_at TEXT");
+  // table, so add it idempotently. Expressed as the store's first schema migration (#4832): the baseline table is
+  // version 1; migration 1→2 adds `leased_at`. The migration stays defensive (checks table_info) so a version-0
+  // file that already ran the pre-convention ad-hoc ALTER is not re-altered into a duplicate-column error.
+  applySchemaMigrations(db, [
+    (migrationDb) => {
+      const hasLeasedAtColumn = migrationDb
+        .prepare("PRAGMA table_info(miner_portfolio_queue)")
+        .all()
+        .some((column) => column.name === "leased_at");
+      if (!hasLeasedAtColumn) migrationDb.exec("ALTER TABLE miner_portfolio_queue ADD COLUMN leased_at TEXT");
+    },
+  ]);
 
   // `rowid` is a stable, unique key assigned once at first insert (re-enqueue updates in place, never re-inserts),
   // so it is a deterministic total-order tie-break: two items sharing a priority AND an `enqueued_at` timestamp
diff --git a/packages/gittensory-miner/lib/run-state.js b/packages/gittensory-miner/lib/run-state.js
index 047e8b1075..f7c890100c 100644
--- a/packages/gittensory-miner/lib/run-state.js
+++ b/packages/gittensory-miner/lib/run-state.js
@@ -1,4 +1,5 @@
 import { normalizeLocalStoreDbPath, openLocalStoreDb, resolveLocalStoreDbPath } from "./local-store.js";
+import { applySchemaMigrations } from "./schema-version.js";
 
 export const RUN_STATES = Object.freeze(["idle", "discovering", "planning", "preparing"]);
 
@@ -41,6 +42,8 @@ export function initRunStateStore(dbPath = resolveRunStateDbPath()) {
       updated_at TEXT NOT NULL
     )
   `);
+  // Schema-version convention (#4832): stamp the baseline and run any post-baseline migrations (none yet).
+  applySchemaMigrations(db, []);
 
   const getStatement = db.prepare(
     "SELECT state FROM miner_run_state WHERE repo_full_name = ?",
diff --git a/packages/gittensory-miner/lib/schema-version.d.ts b/packages/gittensory-miner/lib/schema-version.d.ts
new file mode 100644
index 0000000000..5c52cd1c07
--- /dev/null
+++ b/packages/gittensory-miner/lib/schema-version.d.ts
@@ -0,0 +1,17 @@
+import type { DatabaseSync } from "node:sqlite";
+
+/** A single post-baseline schema migration: mutate the store in place to advance it exactly one version. */
+export type SchemaMigration = (db: DatabaseSync) => void;
+
+/** The bootstrap schema every store creates inline is, by convention, schema version 1. */
+export const BASELINE_SCHEMA_VERSION: number;
+
+/** Read a store's current `PRAGMA user_version`, coercing any absent/invalid value to 0 (pre-versioning). */
+export function readSchemaVersion(db: DatabaseSync): number;
+
+/**
+ * Run pending post-baseline migrations in order and stamp the resulting `user_version`. `migrations[i]` upgrades
+ * from version i+1 to i+2, so the target version is `BASELINE_SCHEMA_VERSION + migrations.length`. Returns the
+ * resulting version.
+ */
+export function applySchemaMigrations(db: DatabaseSync, migrations?: SchemaMigration[]): number;
diff --git a/packages/gittensory-miner/lib/schema-version.js b/packages/gittensory-miner/lib/schema-version.js
new file mode 100644
index 0000000000..8a08eba6e6
--- /dev/null
+++ b/packages/gittensory-miner/lib/schema-version.js
@@ -0,0 +1,56 @@
+// Lightweight schema-versioning convention shared across the miner's local SQLite stores (#4832).
+//
+// Every store bootstraps its tables with `CREATE TABLE IF NOT EXISTS ...` but, until now, carried no
+// `user_version`/migration mechanism at all — so an older on-disk file was silently reused with a stale shape.
+// This module adds the missing convention without the weight of the main product's `migrations/` runner: each
+// store's bootstrap schema is treated as version 1 (BASELINE_SCHEMA_VERSION), and a store's `migrations` array
+// describes ONLY the changes AFTER that baseline (`migrations[i]` upgrades the schema from version i+1 to i+2).
+// `applySchemaMigrations` reads the file's current `PRAGMA user_version`, runs exactly the pending migrations in
+// order, and stamps the new version — so opening an older-schema file runs its outstanding migrations instead of
+// silently continuing on an incompatible shape. A pre-versioning file (user_version 0) already carries the
+// baseline tables (the idempotent `CREATE TABLE IF NOT EXISTS` ran), so it is treated as the baseline before any
+// post-baseline migration is applied. Pure control flow over an injected `DatabaseSync` handle: no IO of its own
+// beyond the PRAGMA read/write and the caller-supplied migration functions, and deterministic given the same
+// handle + migration list.
+
+/** The bootstrap schema every store creates inline is, by convention, schema version 1. */
+export const BASELINE_SCHEMA_VERSION = 1;
+
+/** Read a store's current `PRAGMA user_version`, coercing any absent/invalid value to 0 (pre-versioning). */
+export function readSchemaVersion(db) {
+  const row = db.prepare("PRAGMA user_version").get();
+  const raw = row ? Number(row.user_version) : 0;
+  return Number.isInteger(raw) && raw >= 0 ? raw : 0;
+}
+
+/**
+ * Bring a store's on-disk schema up to date, then stamp its `user_version`. `migrations[i]` upgrades from
+ * version i+1 to i+2, so the target version is `BASELINE_SCHEMA_VERSION + migrations.length`. Every migration
+ * whose resulting version is above the file's current version runs, in order; a file already at (or past) the
+ * target runs none. Returns the resulting version. Never runs a migration twice (the stamped `user_version`
+ * gates re-runs on the next open) and never DOWNGRADES: a file written by newer code with more migrations is
+ * left at its higher version rather than stamped back down.
+ *
+ * @param {import("node:sqlite").DatabaseSync} db - an open store handle whose baseline tables already exist.
+ * @param {Array<(db: import("node:sqlite").DatabaseSync) => void>} [migrations] - post-baseline migrations.
+ * @returns {number} the schema version after applying any pending migrations.
+ */
+export function applySchemaMigrations(db, migrations = []) {
+  const target = BASELINE_SCHEMA_VERSION + migrations.length;
+  const current = readSchemaVersion(db);
+  // A pre-versioning file (0) already holds the baseline schema, so advance from the baseline, not from 0.
+  const effective = current < BASELINE_SCHEMA_VERSION ? BASELINE_SCHEMA_VERSION : current;
+  for (let version = effective; version < target; version += 1) {
+    migrations[version - BASELINE_SCHEMA_VERSION](db);
+  }
+  if (current < target) {
+    // Only ever stamp when UPGRADING. A file written by NEWER code carrying more migrations (current > target)
+    // must be left at its higher version: stamping it back down to `target` would corrupt its version and hide
+    // the migrations it already ran. `user_version` is an integer PRAGMA that cannot be parameterized; `target`
+    // is a computed integer, never caller text, so interpolating it is safe.
+    db.exec(`PRAGMA user_version = ${target}`);
+  }
+  // The resulting on-disk version: `target` after an upgrade, or the file's own higher version when it was
+  // written by newer code (never downgraded).
+  return Math.max(current, target);
+}
diff --git a/test/unit/miner-schema-version.test.ts b/test/unit/miner-schema-version.test.ts
new file mode 100644
index 0000000000..17f8bf6671
--- /dev/null
+++ b/test/unit/miner-schema-version.test.ts
@@ -0,0 +1,111 @@
+import { describe, expect, it } from "vitest";
+import { DatabaseSync } from "node:sqlite";
+import {
+  applySchemaMigrations,
+  readSchemaVersion,
+  BASELINE_SCHEMA_VERSION,
+} from "../../packages/gittensory-miner/lib/schema-version.js";
+
+type Migration = (db: DatabaseSync) => void;
+
+/** A minimal store whose bootstrap table already exists (the `CREATE TABLE IF NOT EXISTS` convention). */
+function freshStore(): DatabaseSync {
+  const db = new DatabaseSync(":memory:");
+  db.exec("CREATE TABLE IF NOT EXISTS t (id INTEGER PRIMARY KEY)");
+  return db;
+}
+
+describe("schema-version migration runner (#4832)", () => {
+  it("treats a pre-versioning file as version 0 and stamps the baseline when there are no migrations", () => {
+    const db = freshStore();
+    expect(readSchemaVersion(db)).toBe(0);
+    expect(applySchemaMigrations(db, [])).toBe(BASELINE_SCHEMA_VERSION);
+    expect(readSchemaVersion(db)).toBe(1);
+    db.close();
+  });
+
+  it("runs every pending migration in order on a pre-versioning file and stamps the target version", () => {
+    const db = freshStore();
+    const calls: number[] = [];
+    const migrations: Migration[] = [
+      (d) => {
+        d.exec("ALTER TABLE t ADD COLUMN a TEXT");
+        calls.push(1);
+      },
+      (d) => {
+        d.exec("ALTER TABLE t ADD COLUMN b TEXT");
+        calls.push(2);
+      },
+    ];
+    expect(applySchemaMigrations(db, migrations)).toBe(3); // baseline 1 + 2 migrations
+    expect(calls).toEqual([1, 2]);
+    expect(readSchemaVersion(db)).toBe(3);
+    db.exec("INSERT INTO t (id, a, b) VALUES (1, 'x', 'y')"); // both added columns exist
+    db.close();
+  });
+
+  it("is idempotent: re-applying the same migrations on an up-to-date file runs none and does not re-stamp", () => {
+    const db = freshStore();
+    let runs = 0;
+    const migrations: Migration[] = [
+      (d) => {
+        d.exec("ALTER TABLE t ADD COLUMN a TEXT");
+        runs += 1;
+      },
+    ];
+    applySchemaMigrations(db, migrations);
+    expect(runs).toBe(1);
+    expect(applySchemaMigrations(db, migrations)).toBe(2);
+    expect(runs).toBe(1); // the already-applied migration did not run again
+    db.close();
+  });
+
+  it("runs only the outstanding migrations when a file is partway through the history", () => {
+    const db = freshStore();
+    // A prior release shipped one migration → file is at version 2.
+    applySchemaMigrations(db, [(d) => d.exec("ALTER TABLE t ADD COLUMN a TEXT")]);
+    expect(readSchemaVersion(db)).toBe(2);
+    const ran: string[] = [];
+    const migrations: Migration[] = [
+      () => ran.push("0"), // already applied — must NOT run
+      (d) => {
+        d.exec("ALTER TABLE t ADD COLUMN b TEXT");
+        ran.push("1");
+      },
+    ];
+    expect(applySchemaMigrations(db, migrations)).toBe(3);
+    expect(ran).toEqual(["1"]);
+    db.close();
+  });
+
+  it("never downgrades a file written by newer code (current > target): no migrations run, version unchanged", () => {
+    const db = freshStore();
+    // Newer code (2 migrations) stamped this file at version 3.
+    applySchemaMigrations(db, [
+      (d) => d.exec("ALTER TABLE t ADD COLUMN a TEXT"),
+      (d) => d.exec("ALTER TABLE t ADD COLUMN b TEXT"),
+    ]);
+    expect(readSchemaVersion(db)).toBe(3);
+    // Older code that only knows one migration opens the same file: it must run nothing and must NOT stamp the
+    // version back down to its own target of 2.
+    let ran = 0;
+    const resulting = applySchemaMigrations(db, [
+      () => {
+        ran += 1;
+      },
+    ]);
+    expect(ran).toBe(0);
+    expect(readSchemaVersion(db)).toBe(3); // left at the newer version, not downgraded to 2
+    expect(resulting).toBe(3); // reports the file's actual (higher) version
+    db.close();
+  });
+
+  it("coerces an absent, non-integer, or negative user_version to 0", () => {
+    const absent = { prepare: () => ({ get: () => undefined }) } as unknown as DatabaseSync;
+    expect(readSchemaVersion(absent)).toBe(0);
+    const nonInteger = { prepare: () => ({ get: () => ({ user_version: "oops" }) }) } as unknown as DatabaseSync;
+    expect(readSchemaVersion(nonInteger)).toBe(0);
+    const negative = { prepare: () => ({ get: () => ({ user_version: -3 }) }) } as unknown as DatabaseSync;
+    expect(readSchemaVersion(negative)).toBe(0);
+  });
+});