Disable mutating tools in read-only mode

[diksipav]

What kind of change does this PR introduce?

Improvement: #112

What is the current behavior?

Read-only mode executes SQL as a read-only Postgres user (execute_sql tool), and
apply_migration tool is disabled in read-only mode.

What is the new behavior?

Alongside execute_sql and apply_migration all other mutating tools are disabled in read-only mode.

[gregnr]

Thanks @diksipav 👍 can we please also add some tests for each of these to validate that the errors are thrown in read only mode?

[diksipav]

Hey @gregnr it seems to me that for e2e testing a real ANTHROPIC_API_KEY is used and we are calling the LLM, right? Also one of the latest (and most expensive models is used). I am testing now with my own api key, but maybe we can at least test with a cheaper model? Also not sure in this case should I test every option or for example to test one tool per each feature group in read-only mode.

Or to not write full e2e tests but to just test tool calls? Maybe to extend server.test.ts.

[gregnr]

@diksipav I think there is no need for e2e tests in this case, let's just stick to unit. The logic is pretty straightforward and probably not worth the cost of running through a real LLM.

The tests you've added to server.test.ts look good.

[gregnr]

Looks good @diksipav 👍 you can ignore the failed E2E tests since these are just due to the missing API key. We'll merge this soon.

[MariusWilsch]

I was wondering why it is not possible to still apply a migration in read-only mode with confirmation, while limiting read-only in execute SQL.

It's kind of annoying because I want to use a migration system with MCP, but it's not possible in the read-only mode.

[gregnr]

Thanks again @diksipav and sorry for the long delay. Merging!