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

Annotations already cover read-only, idempotent, non-destructive behavior, so the bar is lower. The description still adds genuine context beyond them: newest-first ordering, a 50-item page cap, and the fact that parked phones retain apps/sign-ins at no cost. It does not describe error behavior or cursor expiry, but this is solid added value.

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, front-loaded with the core action and scope. The trailing sentence about parked phones is somewhat tangential to a listing tool but justifies itself by explaining the 'when each parks' data the tool returns.

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 read-only, annotation-covered, two-param list tool with no output schema, the description covers ordering, page size, paging, and the meaning of parked. An agent has everything needed to call 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?

Schema description coverage is 100%, so both cursor and status are fully documented in the schema; baseline is 3. The description restates paging ('up to 50 a page, and next_cursor for the next page') but adds no syntax or format detail beyond the schema.

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 this project's phones') and adds return-shape detail (newest first, status, park time). It is implicitly distinguishable from get_phone (singular) and list_apps (different resource), though it never names a sibling explicitly.

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 listing use case is implied by the verb and the project scope, and the schema handles the status-filter edge case. However, the description gives no explicit when-to-use guidance versus get_phone or other read tools, and names no alternatives.

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