hostinger-api-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 the one-active-firewall constraint (valuable context), it doesn't address critical behavioral aspects: whether this is a destructive/mutative operation, what permissions are required, whether it's synchronous/asynchronous, what happens if another firewall is already active, or what the response looks like. For a mutation tool with zero annotation coverage, this leaves significant gaps in understanding the tool's behavior.

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 concise and well-structured: three sentences that each add distinct value. The first states the core purpose, the second provides a critical constraint, and the third gives usage context. There's zero redundancy or wasted words, and the most important information (activating a firewall) is front-loaded.

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 2 parameters, no annotations, and no output schema, the description provides adequate but incomplete context. It covers the basic purpose and a key constraint (one active firewall), but lacks information about behavioral traits, error conditions, response format, and prerequisites. The schema handles parameter documentation well, but the description doesn't compensate for the missing annotation and output information.

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 100%, with both parameters clearly documented in the schema. The description doesn't add any parameter-specific information beyond what's in the schema (firewallId and virtualMachineId). It implies these parameters are needed but provides no additional context about format, validation, or relationships. With complete schema coverage, the baseline score of 3 is appropriate.

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 action ('Activate a firewall') and target resource ('for a specified virtual machine'), making the purpose unambiguous. It distinguishes from obvious siblings like VPS_deactivateFirewallV1 by specifying activation rather than deactivation, though it doesn't explicitly differentiate from all VPS firewall-related 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 clear context about when to use this tool: 'Only one firewall can be active for a virtual machine at a time' and 'Use this endpoint to apply firewall rules to VPS instances.' This gives practical guidance about the one-active-firewall constraint and the application purpose. However, it doesn't explicitly mention when NOT to use it or name specific alternatives among the many sibling tools.

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