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

No annotations exist, so the description carries the full disclosure burden. It does convey that results include human-review status and are candidate (unconfirmed) records, which is useful. However, it never states that this is a read-only operation, whether it returns all agents' candidates or only the caller's, ordering/pagination, or any access constraints.

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 compact sentences with the resource stated first and the clarifying qualifier last. The 'Candidates, not confirmed planets' clause is slightly redundant with 'planet candidates' but does add real epistemic precision about the data's trust level.

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 parameters, no annotations, and no output schema, the description is the only source of behavioral information, and it omits scope (all agents vs. self), return shape, and volume. It is adequate to identify the tool but thin for actually invoking it correctly.

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 meaning to add; baseline 4 applies. Nothing in the description misleads about inputs.

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 names the resource (real-sky planet candidates submitted by agents) and the payload of interest (human-review status), plus a disambiguating clause distinguishing candidates from confirmed planets. The verb 'list/retrieve' is only implicit, and it doesn't explicitly contrast with planets_vet or planets_submit, so it stops short of a 5.

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?

There is no when-to-use guidance, no mention of alternatives such as planets_vet (for reviewing candidates) or planets_submit (for creating them), and no stated preconditions. An agent must infer the browsing use case from the description alone.

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