Improved MCP server with init instructions and server list in query error

[ExtReMLapin]

I was running tests with Qwen code, and it was tasked to run cypher queries on both neo4j and arcadedb.

Goofy qwen didn't bother getting the list of the databases first.

Now, it has instructions to do it first, and even if it fails to do so and go for an non existing base it will get the list of the bases in the error

[gemini-code-assist]

Code Review

This pull request enhances the MCP implementation by adding specific instructions for LLMs and introducing a MCPToolUtils.resolveDatabase utility to provide a list of authorized databases when a requested database is not found. Feedback suggests improving the database filtering logic in the utility for better robustness and centralizing the security authorization check. Currently, manual security checks in the tool classes are performed before the resolution logic, which prevents restricted users from receiving the helpful list of available databases when a typo occurs.

[gemini-code-assist]

Using user.canAccessToDatabase(db) to filter the list is more robust than manually checking for * and using retainAll. This approach correctly leverages the existing security logic in the ServerSecurityUser class, which may include complex rules or wildcards beyond a simple * check.

Suggested change

	final Set<String> installed = new TreeSet<>(server.getDatabaseNames());
	final Set<String> allowed = user.getAuthorizedDatabases();
	if (!allowed.contains("*"))
	installed.retainAll(allowed);
	final Set<String> installed = new TreeSet<>(server.getDatabaseNames());
	installed.removeIf(db -> !user.canAccessToDatabase(db));

[gemini-code-assist]

Consider centralizing the database authorization check here. By moving the canAccessToDatabase check into this utility method, you ensure that all tools using resolveDatabase are consistently protected. Furthermore, this allows the 'Available databases' error message to be reached even when a restricted user makes a typo, which is currently blocked by the manual checks in the tool classes.

    if (!user.canAccessToDatabase(databaseName))
      throw new SecurityException("User '" + user.getName() + "' is not authorized to access database '" + databaseName + "'");
    return server.getDatabase(databaseName);

[gemini-code-assist]

The security check on lines 76-77 (context) is currently executed before resolveDatabase. For restricted users, this means a typo in the database name will trigger a SecurityException instead of the helpful error message containing the list of available databases. Consider moving the authorization check inside resolveDatabase or after it to ensure the 'Available databases' feature works for all users.

[gemini-code-assist]

The manual security check on lines 75-76 (context) prevents restricted users from seeing the list of available databases when they provide an incorrect database name. If the authorization check is moved inside or after resolveDatabase, the LLM will be able to self-correct using the provided list.

[gemini-code-assist]

Similar to other tools, the preceding security check (lines 60-61) blocks the helpful error message for restricted users. Centralizing this check within resolveDatabase would improve the user experience and maintainability.

[codacy-production]

Up to standards ✅

🟢 Issues 0 issues

Results:
0 new issues

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🟢 Metrics 4 complexity

Metric	Results
Complexity	4

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[robfrank]

@ExtReMLapin can you rebase and push again? thanks

[ExtReMLapin]

Done !

[codecov]

Codecov Report

❌ Patch coverage is 81.81818% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 63.78%. Comparing base (4cb5061) to head (ac9f0e8).
⚠️ Report is 23 commits behind head on main.

Files with missing lines	Patch %	Lines
...va/com/arcadedb/server/mcp/tools/MCPToolUtils.java	71.42%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3896      +/-   ##
==========================================
- Coverage   64.46%   63.78%   -0.69%     
==========================================
  Files        1587     1588       +1     
  Lines      118612   118620       +8     
  Branches    25194    25195       +1     
==========================================
- Hits        76468    75659     -809     
- Misses      31548    32483     +935     
+ Partials    10596    10478     -118     

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[robfrank]

supersede by #3966

Thank you for your contribution!