Append a new content block to a link-in-bio page. The block must match one of the 13 allowed types (link, social_row, whatsapp, phone_call, email_contact, image, gallery, video_embed, text, map_embed, product_card, lead_form, reviews) with that type's strict props. The server generates the block ...
Part of the Create Web Page server.
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AI agents use block.add to create or modify resources in Create Web Page. 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 block.add repeatedly, creating or modifying resources faster than any human could review. PolicyLayer's rate limiting ensures write operations happen at a controlled pace, and argument validation catches malformed or unexpected inputs before they reach Create Web Page.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
{
"version": "1",
"default": "deny",
"tools": {
"block.add": {
"limits": [
{
"counter": "block.add_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}See the full Create Web Page policy for all 23 tools.
These attack patterns abuse exactly the kind of access block.add gives an agent. Each links to the full case and the policy that stops it:
Other write tools across the catalogue. The same approach applies to each: rate-limit and validate the arguments.
Append a new content block to a link-in-bio page. The block must match one of the 13 allowed types (link, social_row, whatsapp, phone_call, email_contact, image, gallery, video_embed, text, map_embed, product_card, lead_form, reviews) with that type's strict props. The server generates the block id and returns it in the response. For already-published pages, this saves an unpublished latest revision only. Do not call page.publish in the same assistant turn after this edit. Stop and tell the user the draft/preview was updated, then wait for a separate user message that explicitly asks to update the live link, publish, or make the changes public before calling page.publish. Do NOT call page.unpublish either — the live page should stay public; only unpublish when the user explicitly asks to take it down. The response includes nextSteps: after adding a block, share these hints with the user so they know what else would make the page more complete.. It is categorised as a Write tool in the Create Web Page MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Create Web Page MCP server in PolicyLayer and add a rule for block.add: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Create Web Page. Nothing to install.
block.add 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 block.add rule in your PolicyLayer 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 PolicyLayer policy for block.add. 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.
block.add is provided by the Create Web Page MCP server (https://create-web-page.com/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 23 Create Web Page tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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