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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description earns credit for adding the "either user_id or transaction_id" constraint, which the schema does not enforce (required is empty), but says nothing about result size, pagination, or whether unassigned=true is rejected when transaction_id is used.

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?

Three short sentences, zero filler, with the '{resource} lists' framing and the required-filter constraint front-loaded. Nothing could be cut without losing information.

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?

A small read-only list tool with rich annotations and no output schema does not need much, and the description covers the essential calling constraint. Minor gaps remain around result caps and what happens with invalid parameter combinations.

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 all three parameters are already documented with the same semantics the description provides. The description's phrasing mirrors the schema almost verbatim and adds no syntax or edge-case detail beyond it; baseline 3 applies.

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 ("Lists attachments") and immediately adds the scoping constraint. It is distinguishable from get_attachment and its list_* siblings by resource name alone, though it never names an alternative 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?

Gives clear applicability conditions: one of user_id or transaction_id is required to call it, and unassigned only applies when using user_id. It stops short of saying when to prefer this over get_attachment or list_transactions, but the context is unambiguous.

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