list_attachments

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

Annotations already declare readOnlyHint=true, and the description reinforces this with 'without saving anything to disk', plus discloses what the result contains (attachment names, content types, sizes). It adds useful behavioural context beyond the annotation, though it says nothing about permissions or failure modes.

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 core purpose and the no-disk-write constraint are front-loaded in one efficient sentence; the trailing Args block is mildly redundant formatting but adds no padding. Nothing wasted.

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 an output schema present, return values need not be described, yet the description helpfully indicates the metadata fields. Both parameters and the read-only nature are covered; only auth requirements and error behaviour are absent, which is acceptable for this simple listing tool.

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 0%, so the description must carry the parameter burden — and it does, defining message_id as the Message-ID and folder as the folder containing the message. The only gap is that the INBOX default is left to the schema rather than restated.

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 (List) and resource (a message's attachments) and immediately scopes the output to metadata — names, content types, sizes — which cleanly separates it from save_attachment in the sibling set.

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 'without saving anything to disk' signals the read-only context and implicitly contrasts with save_attachment, giving clear usage context. However, it never names the alternative tool or states an explicit when-to-use condition, so it stops short of a 5.

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