Vultr MCP

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries full burden. It states 'Update access control' implying a mutation, but doesn't disclose behavioral traits like required permissions, whether changes are reversible, rate limits, or error conditions. The return value is mentioned generically ('Status message confirming update'), but lacks detail on format or success/failure indicators.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is well-structured with a purpose statement, 'Args:' section listing parameters, and 'Returns:' section. Every sentence adds value, though the parameter explanations could be more concise (e.g., repeating 'ACL' for each). No fluff or redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given 6 parameters, 0% schema coverage, no annotations, and no output schema, the description does a fair job: it covers all parameters and states the return type. However, as a mutation tool with complex ACL parameters, it lacks details on behavioral impact, error handling, and security implications, leaving gaps for an agent.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must compensate. It lists all 6 parameters with brief explanations and examples (e.g., 'acl_categories: ACL categories (e.g., ["+@all"])'), adding meaningful context beyond the bare schema. However, it doesn't explain parameter interactions, default behaviors, or validation rules.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the verb ('Update') and resource ('access control for a database user'), specifying it's for Valkey/Redis only. It distinguishes itself from generic user update tools by focusing on access control, though it doesn't explicitly differentiate from potential sibling ACL tools (none are listed).

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance is provided on when to use this tool versus alternatives like 'update_user' or 'setup_permissions'. The description mentions 'Valkey/Redis only', which is a platform constraint but not usage context. There are no prerequisites, exclusions, or comparison with sibling tools.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.