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

readOnlyHint=true is already declared by annotations, but the description adds genuine behavioral value by describing the shape of the returned payload (breakdown by mcc/mccMnc, quantity and price per sub-item, optional delivery statuses) and the underlying endpoint. This compensates for the absence of an output schema. It does not cover error/permission behavior, so it stops short of a 5.

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 front-loaded sentence establishes what the record contains, followed by the endpoint path. Nothing is padded, though the raw REST path contributes little for an agent selecting an MCP tool.

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 no output schema and only readOnlyHint in the annotations, the description carries the burden of describing the return payload, and it does so adequately via the breakdown/sub-item/status details. Missing pieces such as error behavior or empty-result handling keep it from a 5.

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%, so all three parameters are already documented in the schema, including the group_by enum values and the detail_statuses flag. The description mirrors that information ('by country (mcc) or network (mccMnc)', 'optionally with delivery statuses') without adding syntax or format detail beyond it, so the baseline of 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?

The description gives a specific verb+resource ('One consumption record') and further scopes it by naming the breakdown dimension and per-sub-item fields. It contrasts implicitly with smsmode_list_consumptions via the singular 'record', but never names the sibling, so differentiation is inferred rather than stated.

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?

There is no explicit when-to-use or when-not-to-use guidance in the description. The usage is inferable from the singular scope (fetch one consumption by id), and the schema notes the id comes from smsmode_list_consumptions, but the description itself does not route the agent among alternatives.

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