Vultr MCP

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

With no annotations provided, the description carries full burden for behavioral disclosure. While it mentions this starts a 'stopped instance' (implying state change), it doesn't cover important behavioral aspects like required permissions, rate limits, whether the operation is idempotent, or what happens if the instance is already running. The description is minimal beyond the basic action.

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 perfectly structured and concise: a clear purpose statement followed by well-organized Args and Returns sections. Every sentence earns its place, with no redundant information. The formatting makes it easy to scan and understand quickly.

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?

For a mutation tool with no annotations and an output schema, the description provides adequate basic information but lacks important context. It covers the purpose and parameter semantics well, but doesn't address behavioral aspects like permissions, idempotency, or error conditions. The presence of an output schema means it doesn't need to explain return values, but other gaps remain.

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?

With 0% schema description coverage for the single parameter, the description provides valuable semantic context by explaining that 'instance_id' can be an ID, label, hostname, or UUID with specific examples ('web-server', 'db.example.com', or UUID). This adds meaningful interpretation beyond the bare schema type declaration.

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 specific action ('Start a stopped instance') with the resource ('instance'), distinguishing it from siblings like 'stop', 'reboot', or 'create'. It uses precise terminology that differentiates this tool's purpose from other instance management tools.

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?

The description provides no guidance on when to use this tool versus alternatives like 'reboot' or 'start_bare_metal_server', nor does it mention prerequisites (e.g., the instance must be in a stopped state). It simply states what the tool does without contextual usage information.

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