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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive, so safety is covered. The description usefully discloses that exactly one external Sonar query is issued (a cost/latency-relevant trait) and that results are ranked by citation presence and position, but it says nothing about failure behavior or partial coverage.

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?

A single dense sentence with no filler; the action, the input shape, and the ranking criterion all land up front.

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?

With no output schema, the description partially carries the burden by sketching the return ('rank ... by whether and where each is cited'), which is enough for an agent to interpret the result. It does not explain the result shape (e.g., per-URL position/absence) or what happens when zero URLs are cited.

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 67% and the description only loosely echoes what the schema says ('competitor URLs', 'for the prompt'), adding no format or syntax detail. The BYOK key parameter is documented only in the schema, which is acceptable given moderate coverage.

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 ('rank'), a specific resource ('several competitor URLs'), and the mechanism ('one Perplexity Sonar query') plus the criterion ('whether and where each is cited'). This is clearly distinct from analyze_website_aeo or get_visibility_report, though it never names those siblings 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?

Usage is implied: you call this when you want a head-to-head citation ranking for a prompt across two or more URLs. There is no explicit 'use this instead of X when...' guidance and no mention of prerequisites, so the agent must infer the boundary from sibling names.

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