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

Annotations only declare readOnlyHint=true. The description adds two genuinely behavioral facts: a 24-hour expiry (a failure mode the agent must plan around) and that the call never purchases a replacement (cost/authorization behavior). Missing is what happens on an expired or unknown id.

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?

Two short sentences, the core action front-loaded, and the expiry constraint placed immediately after. Every clause carries information; nothing is padding.

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 single-parameter read with no output schema, the description covers purpose, lifetime constraint, and cost behavior. It could say a bit more about error behavior on expiry or what the report contains, but it is largely sufficient.

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?

One parameter with 0% schema description coverage, so the description must carry it. 'By report_id' identifies the parameter's role but adds no format, length, or expected-value information beyond the self-evident name.

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 (read) and a precisely scoped resource (a completed public cached report) keyed by report_id. The qualifiers 'completed' and 'cached' distinguish it from the sibling get_scan_status, though no sibling is named explicitly.

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?

'Completed' implies you should only call this once a scan has finished, and 'never purchases a replacement' implies this is not the tool for obtaining a fresh report. Both are inferred rather than stated, and no alternative tool is named for that case.

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