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 modifies authentication credentials reversibly but with high blast radius. This is a Write operation (modification) rather than Read (it actively changes tokens, not just retrieves them), not Execute (doesn't run arbitrary code), and not Destructive (tokens can be regenerated). However, compromised token management could grant unauthorized access to the entire CMS, making this high severity.
From the tool's definition Tool name 'update_access_token' indicates modification of authentication credentials. Storyblok context shows this is a CMS access control mechanism.
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 (arjuncodess/storyblok-mcp). 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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115 Storyblok MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.