Add or remove labels on all messages matching a query. Same fast search-then-batch pattern as bulk_trash, but for arbitrary label ops. Use this for archive (remove_labels=['INBOX']), bulk star/unstar, mark-read across a label, moving messages between labels, etc. Use dry_run to see the count first.
Accepts freeform code/query input (query); Accepts file system path (folder); Bulk/mass operation — affects multiple targets
Part of the Mailbox MCP server. Enforce policies on this tool with Intercept, the open-source MCP proxy.
AI agents use bulk_modify to create or modify resources in Mailbox. Write operations carry medium risk because an autonomous agent could trigger bulk unintended modifications. Rate limits prevent a single agent session from making hundreds of changes in rapid succession. Argument validation ensures the agent passes expected values.
Without a policy, an AI agent could call bulk_modify repeatedly, creating or modifying resources faster than any human could review. Intercept's rate limiting ensures write operations happen at a controlled pace, and argument validation catches malformed or unexpected inputs before they reach Mailbox.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
tools:
bulk_modify:
rules:
- action: allow
rate_limit:
max: 30
window: 60See the full Mailbox policy for all 49 tools.
Agents calling write-class tools like bulk_modify have been implicated in these attack patterns. Read the full case and prevention policy for each:
Other tools in the Write risk category across the catalogue. The same policy patterns (rate-limit, validate) apply to each.
Add or remove labels on all messages matching a query. Same fast search-then-batch pattern as bulk_trash, but for arbitrary label ops. Use this for archive (remove_labels=['INBOX']), bulk star/unstar, mark-read across a label, moving messages between labels, etc. Use dry_run to see the count first.. It is categorised as a Write tool in the Mailbox MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Add a rule in your Intercept YAML policy under the tools section for bulk_modify. You can allow, deny, rate-limit, or validate arguments. Then run Intercept as a proxy in front of the Mailbox MCP server.
bulk_modify is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the bulk_modify rule in your Intercept policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the Intercept policy for bulk_modify. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
bulk_modify is provided by the Mailbox MCP server (mailbox-mcp). Intercept sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic policy on every MCP tool call. Per-identity grants. Full audit log.