ZOHO_MAIL tools broken: account_id typed as integer but Zoho IDs exceed JS safe integer range

[rashid301]

Bug Report

Description

All ZOHO_MAIL_* tools fail silently when the Zoho account ID exceeds JavaScript's safe integer range (Number.MAX_SAFE_INTEGER = 2^53 - 1).

Zoho account IDs are 19-digit numbers (e.g. 6486202000000008002). When passed as a JSON integer, the value is silently truncated due to floating-point precision loss, becoming 6486202000000008000 or similar. The API then either returns empty results (data: []) or a 500 internal error.

Steps to Reproduce

1. Get your Zoho account ID via ZOHO_MAIL_ACCOUNTS_LIST_ACCOUNTS — note it is a 19-digit number
2. Pass that ID to any ZOHO_MAIL_* tool (e.g. ZOHO_MAIL_MESSAGES_LIST_EMAILS) as account_id
3. Observe empty results or 500 error despite valid credentials

Expected Behavior

Tools should accept and correctly pass the full 19-digit account ID to Zoho's API.

Actual Behavior

The integer is silently truncated, Zoho cannot find the account, returns empty results or 500.

Root Cause

The account_id field in the input schema is typed as integer:

"account_id": {
  "type": "integer",
  "minimum": 1,
  "examples": [123456789]
}

Zoho account IDs are 19 digits, which exceeds Number.MAX_SAFE_INTEGER (15-16 significant digits). JSON parsers that use IEEE 754 double-precision floats lose precision on these values.

Fix

Change account_id type from integer to string across all ZOHO_MAIL_* tools:

"account_id": {
  "type": "string",
  "examples": ["6486202000000008002"]
}

This affects at minimum:

• ZOHO_MAIL_MESSAGES_LIST_EMAILS
• ZOHO_MAIL_SEARCH_MESSAGES
• ZOHO_MAIL_MESSAGES_GET_MESSAGE_CONTENT
• ZOHO_MAIL_MESSAGES_REPLY_TO_EMAIL
• ZOHO_MAIL_ACCOUNTS_LIST_ACCOUNTS (return value also affected)

Workaround

Use Zoho's official MCP server (zoho.com/mcp) via mcp-remote instead of the Composio Zoho Mail tools. The official MCP passes account IDs as strings and works correctly.

Environment

• Composio SDK / MCP integration
• Zoho Mail account based in India (.in datacenter)

[Uday-sidagana]

Hey Rashid (@rashid301), we were able to reproduce the issue and we'll be working on the fix for the same. I'll keep you updated.

[Uday-sidagana]

Hi Rashid (@rashid301), we've fixed the issue with Zoho Mail tools. Lmk if you face any issues.