Block & Restrict
Tool blocking lets you control exactly what your AI agent can do — hiding entire tools from view, or stopping specific requests before they execute.
Disable specific tools
Use Hook_Filter with a disabled list to hide tools the AI should never use. Disabled tools don't appear in the AI's tool list at all — it can't call what it can't see.
Example — prevent the AI from deleting calendar events or sending emails:
{ "disabled": ["delete_event", "draft_gmail_message"] }
Ask the Configurator Agent:
"Hide the delete_event tool on my Google Calendar server"
"Remove send capabilities from Gmail — draft only"
Whitelist: only allow specific tools
Use an enabled list to restrict a server to exactly the tools you want. Every other tool on that server is hidden.
Example — lock GitHub to read-only operations:
{ "enabled": ["get_repository", "list_issues", "search_repositories", "get_pull_request"] }
"Limit my GitHub server to search and read tools only"
Whitelisting is the safer default for production agents — you explicitly opt in to each capability rather than blocking known risks.
Block by parameter pattern
Request guardrails block tool calls when an input matches a pattern — even if the tool itself is visible.
Example — block GitHub code searches for secrets:
"Add a guardrail to block code searches containing 'password', 'api_key', or 'secret'"
Example — prevent SQL queries that drop or truncate tables:
"Block any PostgreSQL query containing DROP TABLE or TRUNCATE"
Common blocking patterns by server
| Server | Recommended blocks |
|---|---|
google-calendar | delete_event, modify_event (attendee changes) |
google-gmail | delete_gmail_filter, create_gmail_filter |
google-drive | any file deletion tools |
google-docs | find_and_replace_doc (bulk destructive) |
github-remote | delete_repository, delete_branch |
postgres / mysql | DROP, TRUNCATE, DELETE without WHERE |
slack | delete_message, kick_user_from_channel |
Blocking vs revocation
Blocking (via guardrails) hides or restricts a tool while keeping the server connection intact. Revocation severs the connection entirely.
Use blocking for ongoing least-privilege configuration. Use revocation when responding to an incident.
How to configure
Ask the Configurator Agent in Leadovaro Chat, or configure directly in the Leadovaro UI under your toolkit's guardrail settings.
Action: update
Category: Hook_Filter
MCP Server: google-calendar
Value: { "disabled": ["delete_event"] }