Block & Restrict

Hide tools from the AI entirely, or block requests that match unsafe patterns

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 Civic Chat, or configure directly in the Civic UI under your toolkit’s guardrail settings.

Action: update
Category: Hook_Filter
MCP Server: google-calendar
Value: { "disabled": ["delete_event"] }