Since launching our MCP last year we've seen an awesome uptick in our customers using it to query profiling data and apply performance improvements based on the available data. However, there has been a fundamental problem with how we authenticate access to the MCP, which has kept some users from getting access to it.
The problem
In order to use the MCP, users had to create a project token to configure the MCP client with. This is problematic, because creating one requires the "Owner" role on the organization, which many users don't have, as most users just have access to query Polar Signals, and not the ability to perform administrative tasks. And therein lies the paradox, a user is already able to query data, but to do so via the MCP, they need to be a privileged user, or have a privileged user create a token for them, which on top of all of the aforementioned can't only query data, but also write data.
This is all because project tokens were originally created for our profiler to push data to Polar Signals Cloud. When we created the MCP, we admittedly misappropriated them.
Tokens are also long-lived, so invalidating them requires manual action by an "Owner".
The solution
There is already a well defined solution for all of these problems, which the MCP spec also adopted: Oauth. The idea is that the MCP client uses the user's identity to issue queries for profiling data. Best of all, we just had to implement the spec and it works for any MCP client.
This post is not about how we made that implementation happen (maybe we'll write about that in the future, let us know if you think that'd be interesting!). So without further ado, you can now use your favorite MCP client to query profiling data, authenticating via oauth. No more copying authentication tokens!
Since all tools work slightly differently, we've put together an in-product docs page that makes it easy to get started with your favorite AI.
Claude Code
For example, with Claude Code (works with Claude Desktop and Web as well!):
Cursor
Or with cursor all you need to do is click a button.
Conclusion
Now you can easily use your Polar Signals identity to query the MCP with your favorite AI.
And we're not done here, keep an eye out for more authn/authz improvements coming soon!