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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint. The description adds behavioral context: it explains the meaning of report_count (high = active attack source, null/0 = no malicious activity) and the comment field (names known infrastructure). It also notes that no API key is required ('Keyless'), which is useful operational information beyond the annotations.

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 concise: three sentences that front-load the core purpose, then add behavioral details and a usage note. Every sentence adds value without redundancy or fluff.

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?

The description covers the main output fields (report_count, comment) but does not specify the format or other fields like ASN/owner or abuse contact. There is no output schema to compensate. Additionally, error handling or edge cases (e.g., invalid IP) are not mentioned. For a simple lookup tool, it is adequate but not fully complete.

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?

There is only one parameter 'ip', and the input schema provides a description with examples (e.g., '8.8.8.8'). The tool description does not add further semantics about the parameter beyond what the schema already provides, so the baseline score of 3 applies as schema coverage is 100%.

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 tool's purpose: 'Look up an IPv4 address in the SANS ISC DShield database' and lists specific outputs like attack-report history, ASN/owner, abuse contact, and risk. The verb 'Look up' and resource 'IPv4 address in DShield database' are specific, and the tool is distinct from siblings like 'threat_level' or 'port_activity'.

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 does not explicitly state when to use this tool versus alternatives among the 30+ siblings. It mentions 'Keyless' as an advantage but lacks guidance on scenarios where other tools might be more appropriate, such as when a broader threat assessment or port-level data is needed.

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