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

Annotations already declare readOnly, idempotent, non-destructive, non-open-world behavior, so the safety profile is covered. The description adds genuinely non-obvious behavior: lookups are not license-filtered, non-resource kinds return their search-result shape, and openLicense is defined against the current search filter. Return-format detail is thinner, but the added context is substantive.

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?

Four sentences, front-loaded with the retrieval keys before the return-shape and license caveats. Dense but each sentence carries distinct information; the closing markdown-link rendering instruction is slightly advisory but still actionable for an agent preparing output.

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 compensates by describing what different lookup modes return, the license field semantics, and how to surface the result to a user. Nothing essential for a correct single-fetch call is left unstated.

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%, so baseline is 3, but the description adds meaning beyond the schema: it marks naddr as the preferred handoff from search_content and constrains relays to those returned by list_relays. The author parameter's disambiguation role is echoed rather than expanded, keeping it short of a 5.

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 first sentence states a specific verb (Retrieve), resource (a single piece of content), and three lookup keys with a stated preference order. It also explicitly frames itself as the handoff target for search_content results, separating it from the sibling search tools.

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?

It names when to use naddr (preferred, from a search_content result), when to fall back to d-tag or eventId, and when to pass relays (only those from list_relays). The condition selecting each path is explicit, including the author param for disambiguating duplicate identifiers.

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