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

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint, covering safety. The description adds the cost of $1 per call, which is critical for decision-making, and specifies the scope of information returned. This goes beyond the annotations without contradicting them.

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 two sentences, front-loaded with the primary action ('Look up one CVE'), then lists return contents, provides usage guidance, and notes cost. Every sentence carries value, with no 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?

For a simple lookup tool with strong annotations and clear input schema, the description is complete. It covers what the tool does, what data it returns, when to use it, and the cost. No output schema exists, but the listed return types (CVSS, affected products, patch availability, references) give the agent enough context to interpret results.

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 50%, with previous_scan_id having a full description in the schema. cve_id is self-evident from the tool name and description ('by identifier') and its pattern is defined in the schema. The description adds no new parameter semantics, but the schema covers the essential details.

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 function: 'Look up one CVE by identifier' and enumerates the returned data (CVSS score/vector, affected products, patch availability, references). This is a specific verb+resource pairing that distinguishes it from sibling tools like threat_intel_lookup or vuln_prioritize.

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 clear usage condition: 'Use when a specific CVE ID is already known.' This tells the agent when to invoke it, though it doesn't explicitly state when not to use it or name alternative tools. The condition is enough to guide selection among siblings.

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