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

Annotations already establish readOnly, idempotent, non-destructive, so the safety profile is covered. The description adds real behavioral context beyond that by disclosing that an empty customer_id is silently resolved from the connection record, which affects how an agent should supply arguments and what result set it will get.

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 sentences, no filler, with the core action front-loaded and the argument-resolution caveat following immediately. Every clause carries information an agent needs.

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?

An output schema exists, so return values need not be described, and both parameters are accounted for. The only omission is any hint about result volume or pagination for a list endpoint, which is minor at this complexity level.

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 0%, so the description carries the full burden, and it does: it identifies account_id as the Microsoft Advertising account and explains the empty-string default behavior of customer_id. It does not state ID formats or whether account_id is required versus optional, leaving a small gap.

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 (Lists) and resource (campaigns) scoped to a Microsoft Advertising ad account, which cleanly separates it from list_microsoft_ads and list_microsoft_ad_groups. It does not explicitly name a sibling or contrast its scope with them, so it stops short of the top score.

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?

Usage is only implied: an agent can infer this is the read path for Microsoft campaigns, and create/update/delete_microsoft_campaign are the obvious alternatives, but the description never says when to choose this over them or what prerequisites apply. No exclusions or alternative routing is given.

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