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

Annotations already declare readOnlyHint, destructiveHint and openWorldHint, so the description's 'Read-only' phrasing is largely redundant. Its one genuine contribution is naming the returned fields, which partials compensate for the absent output schema, but no pagination or filtering behavior 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?

A single compact sentence with the resource scoping front-loaded; nothing is wasted. It is arguably under-specified rather than padded, which is the better failure mode.

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 list tool with three filter parameters, no output schema, and low schema coverage, the description omits how to scope results (e.g., by campaign_id or account) and what pagination or volume to expect. An agent can guess the call but not use it well.

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%: account_id has a (non-English) description, while profile_id and campaign_id have none. The description never mentions the parameters at all, so it fails to compensate for the undocumented campaign_id scoping, which is critical for a list tool.

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 ('Read-only list of Sponsored Products ad groups') and even enumerates returned fields (id, name, state, default bid). The 'Sponsored Products' qualifier implicitly distinguishes it from the SB and SD ad group siblings, but it never names those alternatives 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?

There is no guidance on when to use this list versus ads_list_sp_campaigns, ads_list_sp_targets, or the SB/SD equivalents, and no prerequisite or filtering context. An agent must infer usage entirely from the tool name.

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