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

Annotations already provide safety hints (readOnly, idempotent, non-destructive). The description adds significant detail: it scores candidate regions, groups by source, and flags client-side rendering, plus mentions pricing, going well beyond annotations.

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 with no extraneous details. The main purpose is front-loaded, and every clause adds value (method, use case, limitation, pricing).

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 tool with an output schema, the description covers purpose, method, use case, limitation (client-side JS), and pricing. No missing information that would hinder proper invocation.

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 a single 'url' parameter described simply as 'Public URL to extract navigation from'. The description does not add meaning beyond the schema for this parameter; the behavioral details are orthogonal.

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 identifies the tool as a 'Navigation extractor' and explains it pulls a site's navigation links by scoring candidate regions, differentiating from siblings like get_seo_links which likely extracts all links.

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?

Description explicitly states it is 'For agents mapping site structure or planning which pages to fetch' and notes it reads server-rendered HTML, providing clear usage context. It does not explicitly state when not to use but implies limitations via client-side rendering flag.

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