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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description is not burdened with that. It adds value beyond annotations by disclosing the return shape — one-line summary and world_id — which matters since no output schema exists. It does not mention pagination, ordering, or behavior when the person has no worlds, leaving a small gap.

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 sentence with the resource and the returned fields front-loaded; every clause adds information (resource meaning, return content, downstream key). No filler.

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 simple zero-param read tool with rich annotations but no output schema, the description covers purpose and return content adequately. Empty-state behavior and ordering are unstated but are minor omissions for a list call.

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?

The tool takes zero parameters, so there is no parameter semantics to explain; the baseline for a parameterless tool applies. The description correctly implies no filtering or scoping inputs are needed.

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 and resource ('List the person's LoreKeeper worlds') and immediately disambiguates the term with a parenthetical defining worlds as D&D/tabletop RPG campaigns and settings. It also specifies the payload (one-line summary plus world_id), so the agent knows exactly what comes back.

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 phrase 'the world_id that every other tool takes' implicitly positions this as the discovery entry point before using sibling tools, which is clear context for invocation ordering. There is no explicit when-not guidance, but with no overlapping sibling (all others operate on characters or lore) there is little ambiguity to resolve.

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