Activate firewall

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

The annotations only declare readOnlyHint=false and destructiveHint=false; the description adds meaningful behavioral context by disclosing the one-active-firewall-per-VM constraint. This helps the agent understand the state-changing impact of calling the tool, including the implicit replacement of an existing active firewall.

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 short and front-loaded with the core purpose. The final sentence, 'Use this endpoint to apply firewall rules to VPS instances,' is somewhat redundant with the first sentence, but the overall structure is efficient and easy to parse.

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 simple two-parameter endpoint with no output schema, the description is reasonably complete. It covers the action, the target resource, and the most important constraint (only one active firewall per VM). Missing details like what happens if no firewall exists or whether the operation is idempotent are minor for this complexity level.

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?

The input schema already documents both parameters with 100% coverage: firewallId and virtualMachineId. The description adds no additional parameter-level meaning, so a 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 states a specific action ('Activate') and resource ('firewall for a specified virtual machine'), making the core purpose clear. It does not explicitly name sibling tools like VPS_deactivateFirewallV1 or VPS_syncFirewallV1, but the verb and resource are specific enough to identify the operation.

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 a key usage constraint: 'Only one firewall can be active for a virtual machine at a time.' This implies the activation will replace any existing active firewall, which is valuable. However, it does not explicitly state when to prefer this tool over related firewall tools or note prerequisites such as creating a firewall first.

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