list_messages

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

Annotations already declare readOnlyHint=true and idempotentHint=true, and the description redundantly states 'read-only'. It adds no further behavioral context such as pagination behavior, ordering, or completeness of results. It is consistent with annotations, so no contradiction, but adds little beyond them.

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?

The description is extremely short, front-loaded, and has no obvious filler. However, the phrase 'read-only' duplicates an annotation, so not every part adds new value. It is concise but slightly under-informative.

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 list operation, the minimal purpose is clear, and annotations cover the safety profile. But with no output schema, an empty list response, pagination behavior, and the relationship to sibling tools like get_message are not described. This leaves an agent uncertain about the exact result format and pagination handling.

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 only 33%: only student_id has a schema description, and that description already says it comes from list_students. The tool description does not clarify page or limit parameters, their defaults, or how pagination works. Since coverage is low, the description should compensate but does not.

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 states the operation clearly: listing a child's messages, and identifies the resource ('child's messages'). It does not explicitly name sibling alternatives, so it doesn't fully distinguish itself from 'get_message', but the 'list' vs 'get' contrast is implicit.

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 provides no guidance on when to use this tool versus alternatives like get_message or list_students. It does not state any prerequisites or exclusions. The only hint is the schema description for student_id, which is not part of the tool description.

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