compare_sites

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

With no annotations, the description carries the burden of disclosure. It discloses the API key requirement, the per-call cost, concurrent scanning behavior, threshold used for competitive gaps, and output includes generated fix code. It does not explicitly state read-only or lack of side effects, but 'scans' and the analysis nature imply non-destructive behavior.

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 front-loaded with the core purpose and outputs, followed by a clear usage condition and then practical prerequisites. It is a bit dense, but each sentence contributes information about behavior, usage, or costs.

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?

The description offers enough for an agent to choose and call the tool: purpose, usage triggers, API key, cost, and output summary. An output schema exists, so the need to document return values is reduced. The main lacking aspect is parameter explanations, but those are already penalized in the parameter semantics dimension.

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 0%, so the description must compensate for all parameters. It indirectly maps url and competitor_url via 'two sites concurrently,' but pages is entirely undocumented in both the schema and description. An agent would not know what 'pages' controls, making this clear gap.

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: 'Competitive gap analysis — scans two sites concurrently, shows side-by-side scores, category-by-category winners, competitive gaps...' This is a specific verb and resource, and it distinguishes compare_sites from sibling tools like scan_site by focusing on two-site comparison and competitor benchmarking.

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 explicitly says 'Use when the user wants to benchmark against a competitor or when scan_site detects competitors in the AI Identity Card,' giving clear triggers for usage. It does not explicitly state when not to use the tool, but the provided context is sufficient to infer it is for competitor comparison rather than single-site audits.

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