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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false, openWorldHint=true), so the description's added value is describing what comes back — relative scores, category gaps, unique weaknesses — which matters because there is no output schema. It stops short of noting caching behavior, cost/latency for 5 domains, or what happens when a domain fails to resolve.

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?

Three short sentences with zero filler: what it does, what it returns, when to use it — in that order. Nothing repeats the name or title verbatim.

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 read-only, fully-documented three-parameter tool with no output schema, the description covers purpose, output shape, and trigger conditions well. The remaining gap is sibling routing — nothing tells the agent when compare_baseline is the better call.

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%, so all three parameters (domains, format, force_refresh) are already documented in the schema, including the 2–5 bound and the enum. The description only echoes the domain-count constraint and adds nothing about the format enum or refresh trade-off; baseline 3 applies.

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 and resource ("side-by-side security comparison of 2–5 domains") plus what the output contains (relative scores, category gaps, unique weaknesses). It is clear on its own, but does not differentiate from the close sibling compare_baseline or explain why one would pick this over repeated scan_domain calls.

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 names the usage context: comparing your posture against a competitor, or a head-to-head between multiple domains. That is a clear positive trigger, but there are no exclusions or named alternatives (compare_baseline is the obvious one left unaddressed).

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