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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds genuinely useful behavioral context beyond that: 'Metadata only; file bytes are not downloaded' tells the agent it cannot retrieve file contents, and the return shape {count, files} is disclosed.

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 tight sentences, front-loaded with purpose and returned fields, then behavior and return shape. Every clause carries information with no filler.

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 tool with no output schema, the description covers the returned fields, the metadata-only limitation, the optional scoping, and the return envelope. Nothing an agent needs to invoke it correctly is missing.

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 coverage is 100%, so pagination, filter, sort and related_id are all already documented in the schema. The description only restates related_id's single-record scoping, adding little beyond the structured fields. Baseline 3 applies when the schema does the heavy lifting.

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 file attachments') and enumerates the returned fields (filename, content type, size, file type, contact/job). It is the only file-oriented tool among the siblings, so the scope is unambiguous and an agent can distinguish it from the contact/job/task listers.

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 explains the scoping option ('optionally for one record (related_id)'), which is the main usage decision for this tool. It does not name when-not-to-use or alternatives, but no sibling offers an equivalent file-listing capability, so the missing exclusions are minor.

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