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

Annotations only tell the agent this is a non-readonly, open-world, non-destructive call. The description adds the crucial behavioral facts the annotations omit: there is no preview and no confirm step, the ticket is real and visible to the service desk the moment the call returns, and urgency defaults to 3. That goes well beyond the structured hints.

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?

Front-loads the most consequential fact (real, immediate, no confirm step) in the first clause, then layers user-agreement guidance, the default, the return shape, and the sibling routing. Every sentence earns its place with no filler.

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?

An output schema exists, so return details need not be explained, yet the description still names the incident number, sys_id, and link. Combined with the safety annotations and the sibling routing, an agent has everything needed to call this correctly without side effects.

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 coverage is 100%, so the schema already documents every field and even carries the urgency default. The description still adds value by singling out short_description and urgency as the fields that must be agreed with the user beforehand, and by restating the default, giving the agent a workflow lens on the parameters.

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?

States a specific verb (creates) and resource (a real incident in the connected ServiceNow instance), and distinguishes itself from siblings by naming servicenow_add_comment and servicenow_update_incident as the alternatives for touching existing incidents. An agent can place it immediately in the ServiceNow tool family.

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?

Explicitly routes the agent: use servicenow_add_comment or servicenow_update_incident instead of creating a duplicate, and agree on short_description and urgency with the user before calling. Both the when-to-use and when-not-to-use cases are stated.

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