This is how you secure AI access to financial and project data
Secure AI access with minimal data sets, OAuth, tenant isolation, read-only tools, limits, current revocation, and content-free audit logs.
By Auke Westra
Founder of DigiData
Short answer
Secure AI access starts with minimal, server-side permissions. Use a per-user and tenant connection, explicitly choose sources, tables, and columns, offer read-only tools, limit each query, and check connection status and role on each call. Do not share a long-lived OData API key with an external assistant.
Start with data minimization
Financial and project data often contains customer data, amounts, employees, planning and contract information. The first security question is therefore not which model you choose, but what data the use case actually needs.
Create an allowlist of sources, tables and columns per connection. For example, a question about outstanding items does not need to be able to read salary or HR columns. A project margin analysis does not automatically have to see every financial table.
Hold permission server-side
A token must identify the user, tenant, connection, target group and rough scope. The detailed field permission remains in DigiData and is reloaded with each tool call. This means that a change takes effect immediately and a model cannot continue to use an old column list from a token.
The tenant is never provided by the model. DigiData derives this from the validated user and connection. Read more about these controls at MCP Safety.
Use OAuth, no copied API key
An OData API key in an external chat is more difficult to manage per user, client and dataset. Remote DigiData MCP therefore uses OAuth with PKCE, resource binding and short access tokens. An administrator reviews a clear consent screen and can revoke the connection.
Make the toolset demonstrably read-only
A read-only MCP server should not have a hidden write route. Tool names and descriptions should make it clear that they read schemas, query bounded records, perform aggregations, or show synchronization status. No create, update, delete, execute, send or approve; no free SQL either.
Read-only limits the impact, but does not prevent a data leak via too broad a selection or a second external tool. Prompt injection into a text field can mislead a model. Therefore, continue to limit outgoing data and do not let the client choose a new destination or additional tenant.
Limit costs and output
Check all selection, filter, sort and group fields against the allowlist. Set limits for rows, bytes, time, and complexity. Let the database be grouped and aggregated first, so the assistant gets a small result instead of a wide recordset.
Audit without content
For support and incident investigations, tool name, time, duration, counts, safe error category, and correlation ID are useful. Prompts, filter values, tokens, and result rows do not belong in analytics or audit logs. This keeps observability usable without creating a second repository for corporate content.
Manage the lifecycle
Periodically check owner, purpose and last used time. Revoke unused connections and test that a revoked or demoted user is rejected on the next call. In addition, keep a tenant and global shutdown option available.
External provider remains a separate assessment
DigiData can secure the outgoing selection, but cannot make all storage and training conditions of every external subscription the same. Determine which ChatGPT or Claude workspace is allowed and who manages provider settings. The privacy equation helps explain that boundary.
Finally, use MCP Troubleshooting to diagnose securely without sharing tokens or customer records with support.
Sources

About Auke Westra
Founder of DigiData
Auke Westra is Founder of DigiData and writes about data integrations, OData and Power BI.
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