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

With empty annotations, the description carries the burden of disclosure. It mentions auth scoping, per-phone filtering, and sort order, which is good. It does not disclose pagination behavior or what the returned run objects look like, leaving gaps for a tool with no output schema.

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 dense sentence with no filler. The verb, scope, and order are front-loaded, making it easy to scan.

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 list operation, the description covers the essential invocation context (auth, one phone, ordering). However, since there is no output schema, the lack of any hint about the return shape or pagination limits leaves some uncertainty. Overall it is minimally viable with clear gaps.

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%; both page and slot are documented there. The description adds only the 'one phone' context, which reinforces the slot parameter. This meets the baseline for schema-covered parameters.

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 uses a specific verb and resource ('List the phone runs'), and scopes it to 'authenticated user' and 'for one phone', which differentiates it from list-phones and get-phone-run. The ordering 'newest first' adds useful detail. This is clear and non-tautological.

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 gives context (authenticated, one phone) but does not name alternatives or state when not to use it. The slot schema reference to 'list-phones' is helpful but lives in the schema, not the description. Usage is implied rather than explicit.

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