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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and a closed world, so safety is covered. The description adds meaningful read-shape context by enumerating the returned fields and the derived counts (posts working / waiting on owner / approved), which matters because there is no output schema. It stops short of noting result size, ordering, or pagination.

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, zero padding. The field enumeration comes first and the routing guidance second, so the most decision-relevant information is front-loaded.

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 read-only list tool with full parameter coverage and no output schema, the description supplies the return-field detail an agent would otherwise lack. The only gap is operational: no mention of ordering, result limits, or whether campaigns are paginated.

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?

There is a single parameter with 100% schema description coverage ('The brand's id, from list_brands.'), so the schema already does the work. The description adds nothing about the brandId itself, so the 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?

The description states a specific verb (lists), the resource (a brand's campaigns), and enumerates the returned fields (id, objective, angle, channels, status, post counts). It also explicitly distinguishes itself from siblings by noting that no other campaign/post tool can look a campaign up by name.

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?

It states the concrete use case ('find a campaignId for an existing campaign') and pre-empts the obvious alternative by asserting that no sibling tool supports name-based lookup. An agent knows exactly when to reach for this tool versus list_posts, get_post, or generate_campaign.

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