AI agents use update_access_token to create or update resources in Storyblok MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Storyblok MCP Server environment.
Updating access tokens is a reversible write operation that modifies security credentials. While not immediately destructive, a compromised token update could grant unauthorized access to all Storyblok resources. Severity is high due to the blast radius: a malicious token update could lock out legitimate users or enable unauthorized access to content management systems.
From the tool's definition Tool name 'update_access_token' indicates modification of authentication credentials. The Storyblok MCP Server description states it 'directly access and manage your Storyblok spaces, stories, components, assets, workflows, and more,' implying token updates…
Documented attack patterns abuse exactly the kind of access update_access_token gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Storyblok MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for update_access_token:
{
"version": "1",
"default": "deny",
"tools": {
"update_access_token": {
"limits": [
{
"counter": "update_access_token_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}update_access_token stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
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update_access_token. It is categorised as a Write tool in the Storyblok MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Storyblok MCP Server MCP server in PolicyLayer and add a rule for update_access_token: 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 Storyblok MCP Server. Nothing to install.
update_access_token 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 update_access_token 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 update_access_token. 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.
update_access_token is provided by the Storyblok MCP Server MCP server (kiran1689/storyblok-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Storyblok MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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159 Storyblok MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.