diff --git a/packages/engine/src/cli/spreadsheets.ts b/packages/engine/src/cli/spreadsheets.ts
index 717a09a..78f39c4 100644
--- a/packages/engine/src/cli/spreadsheets.ts
+++ b/packages/engine/src/cli/spreadsheets.ts
@@ -10,59 +10,95 @@ export const describe = 'Executes operations on Google Spreadsheets';
 export const handler = async (argv: SheetsArgv) => {
   switch (argv.subcommand) {
     case 'fetch': {
-      return fetchSheet();
+      return fetchSheet(argv);
+    }
+    case 'probe': {
+      return probeSheet(argv);
+    }
+    default: {
+      throw new Error(`Unknown subcommand: ${(argv as any).subcommand}`);
     }
   }
+};
 
-  async function fetchSheet() {
-    const { fileDatabase, googleAPIs } = await compose();
+async function fetchSheet(argv: SpreadsheetsFetchArgv) {
+  const { fileDatabase, googleAPIs } = await compose();
 
-    const config = await fileDatabase.spreadsheets.findById(argv.id);
-    if (!config) {
-      throw new Error(`Cannot find the spreadsheet: ${argv.id}`);
-    }
+  const config = await fileDatabase.spreadsheets.findById(argv.id);
+  if (!config) {
+    throw new Error(`Cannot find the spreadsheet: ${argv.id}`);
+  }
+
+  const driveDocument = googleAPIs.driveDocument(config.google_id);
+  const permissions = await driveDocument.getPermissions();
+  const newPermissions = permissions
+    .filter((p) => p.type === 'user')
+    .map(
+      (p) =>
+        ({
+          name: p.displayName!,
+          email: p.emailAddress!,
+          role: p.role!,
+        } as DrivePermission),
+    );
+
+  await fileDatabase.spreadsheets.update(argv.id, {
+    permissions: newPermissions,
+  });
 
-    const driveDocument = googleAPIs.driveDocument(config.google_id);
-    const permissions = await driveDocument.getPermissions();
-    const newPermissions = permissions
-      .filter((p) => p.type === 'user')
-      .map(
-        (p) =>
-          ({
-            name: p.displayName!,
-            email: p.emailAddress!,
-            role: p.role!,
-          } as DrivePermission),
-      );
-
-    await fileDatabase.spreadsheets.update(argv.id, {
-      permissions: newPermissions,
-    });
-
-    const sheetDocument = googleAPIs.spreadsheet(config.google_id);
-    const sheets = await sheetDocument.getSheets();
-    const newSheets = sheets.map((s) => ({
-      name: s.title!,
-      ranges: s.protectedRanges.map(
-        (r) =>
-          ({
-            name: r.description,
-            range: r.range,
-            warn: r.warningOnly,
-            editors: r.editors?.users,
-          } as Range),
-      ),
-    }));
-
-    await fileDatabase.spreadsheets.update(argv.id, {
-      sheets: newSheets,
-    });
+  const sheetDocument = googleAPIs.spreadsheet(config.google_id);
+  const sheets = await sheetDocument.getSheets();
+  const newSheets = sheets.map((s) => ({
+    name: s.title!,
+    ranges: s.protectedRanges.map(
+      (r) =>
+        ({
+          name: r.description,
+          range: r.range,
+          warn: r.warningOnly,
+          editors: r.editors?.users,
+        } as Range),
+    ),
+  }));
+
+  await fileDatabase.spreadsheets.update(argv.id, {
+    sheets: newSheets,
+  });
+}
+
+async function probeSheet(argv: SpreadsheetsProbeArgv) {
+  const { fileDatabase, googleAPIs } = await compose();
+
+  const config = await fileDatabase.spreadsheets.findById(argv.id);
+  if (!config) {
+    throw new Error(`Cannot find the spreadsheet: ${argv.id}`);
+  }
+
+  const spreadsheet = googleAPIs.spreadsheet(config.google_id);
+  const sheet = await spreadsheet.getSheetByTitle(argv.sheet);
+  if (!sheet) {
+    throw new Error(`Cannot find the sheet: ${argv.sheet}`);
   }
-};
+
+  sheet.batch.updateRows({
+    sheetId: sheet.id,
+    startRowIndex: argv.row - 1,
+    startColumnIndex: convertLetterToIndex(argv.column),
+    values: [[argv.value]],
+    notes: argv.note ? [[argv.note]] : undefined,
+  });
+
+  await sheet.flush();
+}
+
+function convertLetterToIndex(letter: string) {
+  // eslint-disable-next-line unicorn/prefer-code-point
+  return letter.charCodeAt(0) - 'A'.charCodeAt(0);
+}
 
 export const builder: CommandBuilder<SheetsArgv, any> = {
   subcommand: {
-    choices: ['fetch'],
+    choices: ['fetch', 'probe'],
     description: 'Subcommand to execute',
     demandOption: true,
   },
@@ -70,9 +106,37 @@ export const builder: CommandBuilder<SheetsArgv, any> = {
     description: 'ID of the spreadsheet to fetch',
     demandOption: true,
   },
+  sheet: {
+    description: '[probe] Title of the sheet to probe',
+  },
+  row: {
+    description: '[probe] Row index to probe',
+    type: 'number',
+  },
+  column: {
+    description: '[probe] Column to probe (A..Z)',
+  },
+  value: {
+    description: '[probe] Value to update in the cell',
+  },
+  note: {
+    description: '[probe] Note to update in the cell',
+  },
 };
 
-export type SheetsArgv = {
+export type SheetsArgv = SpreadsheetsFetchArgv | SpreadsheetsProbeArgv;
+
+export type SpreadsheetsFetchArgv = {
   subcommand: 'fetch';
   id: string;
 };
+
+export type SpreadsheetsProbeArgv = {
+  subcommand: 'probe';
+  id: string;
+  sheet: string;
+  row: number;
+  column: string;
+  value: string;
+  note: string;
+};