Set or update the access token for Microsoft Graph authentication. Use this when the MCP Client has obtained a fresh token through interactive authentication.
AI agents use set-access-token to create or update resources in Lokka (Microsoft 365 MCP server) — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Lokka (Microsoft 365 MCP server) environment.
This tool updates (writes) authentication credentials that gate access to potentially sensitive Microsoft 365 data and operations. While it does not directly modify tenant data, it reconfigures the authentication mechanism that enables all downstream Write, Execute, and Destructive operations on the server.
From the tool's definition Tool description states 'Set or update the access token' — this modifies authentication state that controls subsequent access to Microsoft 365 resources.
Documented attack patterns abuse exactly the kind of access set-access-token gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Lokka (Microsoft 365 MCP server), and nothing reaches the server without passing your rules. This is the rule we recommend for set-access-token:
{
"version": "1",
"default": "deny",
"tools": {
"set-access-token": {
"limits": [
{
"counter": "set-access-token_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}set-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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Set or update the access token for Microsoft Graph authentication. Use this when the MCP Client has obtained a fresh token through interactive authentication. It is categorised as a Write tool in the Lokka (Microsoft 365 MCP server) MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Lokka (Microsoft 365 MCP server) MCP server in PolicyLayer and add a rule for set-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 Lokka (Microsoft 365 MCP server). Nothing to install.
set-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 set-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 set-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.
set-access-token is provided by the Lokka (Microsoft 365 MCP server) MCP server (merill/lokka). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Lokka (Microsoft 365 MCP server), add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
4 Lokka (Microsoft 365 MCP server) tools catalogued and risk-classified — across an index of 43,000+ MCP servers.