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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds one behavioral fact beyond that — only 'analyzed' sources are returned — but says nothing about pagination, ordering, or the cursor semantics that the schema's `before` param warns can skip same-millisecond items.

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 with no filler, and the scoping qualifier ('analyzed', 'for a brand') comes before anything else. However appropriate, it is arguably too terse for a paginated list 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?

For a simple read-only list with no output schema, the description covers what is enumerated but not how enumeration works — no mention of paging, default limit, or result ordering. The agent can call it, but cannot reason about paging behavior from the description alone.

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%: `before` is documented in the schema, but `brandId` and `limit` are not, and the description never mentions them. 'Available to a brand' weakly implies brand scoping, but the limit cap and page-size behavior are undocumented in both places.

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 ('List') and a specific resource ('analyzed source URLs available to a brand'), which is enough to separate it from list_media_library and list_content. It never names or contrasts a sibling, so the differentiation is left to the agent's inference.

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 when-to-use guidance, no exclusions, and no pointer to alternatives such as get_content_source for a single source or create_content_source for adding one. The agent must guess the retrieval context entirely.

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