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

Annotations already declare readOnlyHint and idempotentHint, so no contradiction. The description adds value by disclosing the tool's limited scope (only top 5,000 domains) and the type of data returned (previous-crawl rank, referring subnets), which is not evident from annotations alone. However, it does not detail data freshness or availability.

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 compact yet dense, front-loading the core purpose and scope, then efficiently listing metrics and the alternative. Every sentence adds essential information with no redundancy.

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 read-only tool with 100% schema coverage and no output schema, the description is quite complete. It clearly defines scope, domain eligibility, and provides an alternative for out-of-scope cases. Minor gap: no mention of output format or potential errors, but this is low risk.

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 the schema fully describes the 'domain' parameter. The description adds semantic richness by specifying what constitutes a valid domain (registrable domain) in the schema and hinting at expected usage (popular websites). This elevates it slightly above baseline.

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 computes link-graph rank for popular websites (top 5,000), listing the specific metrics (harmonic-centrality, PageRank, Majestic Million rank) and explicitly excluding other domains. It distinguishes itself from siblings by specifying a niche scope.

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 states when to use this tool (popular websites within top 5,000) and when not to (for other domains), directing the agent to an alternative: 'For any other domain use Linkheft on Apify.' This provides clear routing and prerequisites.

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