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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds genuinely useful context beyond that: no API key required, no payment, and a cap of 20 queries/session. It does not disclose what the preview response contains or that the question field is merely echoed back rather than answered.

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 free/no-key message is stated twice ('✅ No API key needed' and 'FREE preview — no key, no payment'), and the listing price is front-loaded ahead of what the tool does. The sample questions are useful, but the sentence budget is spent partly on marketing rather than operational detail.

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-optional-parameter read-only tool with no output schema, the definition covers access cost and rate limits, which is the main operational risk. It still omits what the returned preview looks like and how it differs from a real data_session_query result, leaving an agent unsure what it will actually get.

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% for both optional parameters, so the schema already explains slug routing and that question is echoed back. The sample questions in the description loosely illustrate the question field but add no syntax or constraint detail beyond the schema's maxLength and defaults.

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 identifies the listing ('govulnwatch: Go Vulnerability Database Tracker') and calls itself a 'FREE preview', so an agent can infer it samples a paid listing. However, it never states a concrete verb or what a preview actually returns (public metadata), and the pricing line '0.01 USDC/query' describes the underlying listing rather than this tool, which muddies rather than clarifies purpose.

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?

'Try one of the sample questions now' plus 'no key, no payment' implies this is the zero-commitment entry point before paying. But there is no explicit when-to-use versus siblings like data_session_query or data_session_open, and no statement of when this tool is insufficient (e.g., needing actual paid query results).

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