compare_domains

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds context on the output (scores, gaps, weaknesses) but does not contradict annotations. It does not disclose additional behavioral traits such as caching behavior (though force_refresh parameter hints at it) or potential side effects, but given the strong annotation coverage, the description is adequate.

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 sentences: the first defines the core functionality, the second provides usage context. Every word earns its place; no redundancy or filler.

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?

Given 3 simple parameters, no output schema, and good annotations, the description covers the tool's purpose and use cases. It explains what the output contains (relative scores, category gaps, unique weaknesses), which is sufficient for understanding. A slight gap is the lack of explicit mention of output format, but it's implied and the tool is simple.

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 coverage is 100% with all parameters described. The description reiterates the domain count range ('2–5 domains') and mentions auto-detection for format, but does not add significant new meaning beyond the schema. Baseline 3 is appropriate since the schema already provides clear definitions.

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 uses specific verbs ('compare', 'shows') and defines the resource ('security comparison of 2–5 domains'). It explicitly lists what it shows (relative scores, category gaps, unique weaknesses), which distinguishes it from sibling tools like check_* (individual checks) and scan_domain (single domain scan).

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 clearly states when to use this tool: 'when comparing your security posture against a competitor, or doing a head-to-head comparison between multiple domains.' It does not explicitly mention when not to use or provide alternatives, but the context is sufficient for correct selection.

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