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

Annotations already provide readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds specific behavioral details such as 'check expiry date' and 'list scopes,' which go beyond the annotations. It does not contradict the structured hints and offers useful context about the token validation process.

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 concise sentence that efficiently enumerates the tool's capabilities. No redundant phrasing, front-loaded with core actions. This is exemplary conciseness.

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?

Given the lack of output schema and the undocumented parameter, the description is under-specified. It does not mention what the tool returns (though 'list' implies some output) or how the auth_account parameter should be used. The tool's complexity is low, but the missing parameter explanation and lack of return format limit its completeness for an agent to correctly invoke it.

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?

The schema has one parameter (auth_account) with no description, and schema_description_coverage is 0%. The description does not explain the purpose or expected format of this parameter. An agent has no clue whether to pass a token, account ID, or something else. The description entirely fails to compensate for the missing schema documentation.

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 clearly states the tool's actions: 'Validate Facebook token, check expiry date, list connected ad accounts and scopes.' It uses a specific verb-resource structure and distinguishes the tool's diagnostic purpose from sibling listing tools like meta_ads_list_accounts and meta_ads_business_accounts. The scope is unambiguous.

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?

No explicit guidance on when to use this tool versus alternatives. The description simply states what it does without indicating prerequisites, typical workflows, or when to prefer sibling tools. The context of many account-listing tools suggests this might be a pre-flight check, but that is not stated.

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