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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds behavior they cannot express: result ordering (newest first), pagination defaults (20 per page, next_cursor for more), and content exclusions. It does not mention auth or rate limits, but those are low-value here.

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?

Three tightly packed sentences ordered as identity → pay-off/relations → exclusions and paging. No filler; even the parenthetical '(source_note)' earns its place as a field mapping.

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?

With an output schema present, enumerating return fields is somewhat redundant, but the description still supplies the ordering, pagination, and cross-tool linkage an agent needs to chain into create_post. The remaining gap is that it doesn't confirm kind/aspect act as optional filters.

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 coverage is 60%: brand, limit, and cursor are documented in the schema, while kind and aspect are bare enums. The description names kind and aspect but as returned fields, not as filter parameters, so it does not clarify that they constrain the listing. Marginal added value over the schema — 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?

States a specific resource (a brand's uploaded media), its ordering (newest first), and the exact fields returned. It distinguishes itself from siblings by name: get/add_media imply single-item or insert operations, and it explicitly demarcates suggest_cover as the tool for video cover frames.

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?

Gives clear downstream context ('These media_id values are what create_post takes') and one explicit exclusion that routes the agent elsewhere ('Candidate cover frames are left out; suggest_cover lists a video's'). It stops short of a full when/when-not framework — it never contrasts itself with get_media or list_posts directly — but the routing guidance is concrete.

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