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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false, openWorldHint=false), so the bar is lower. The description nonetheless adds useful behavior beyond them: deterministic ordering (newest first), fixed page size, and the fact that returned entries include a public URL — all of which matter for correct consumption.

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?

One tightly constructed sentence front-loads the verb and resource, then appends ordering, page size, and the return-value hint in a compact em-dash clause. No filler, no restatement of the tool name.

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 single-optional-parameter read-only list tool with no output schema, the description supplies everything an agent needs: what is listed, ordering, page size, and what each entry yields (a public URL) plus where that URL is consumed. Nothing material is missing.

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 100% and the single `page` parameter is already documented in the schema. The description repeats the 24-per-page fact and adds the ordering semantic ('newest first'), which is not in the schema, but it offers no pagination-end or out-of-range guidance. Baseline 3 is appropriate.

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 resource (user's uploaded media library) plus scope details (newest first, 24/page). An agent can immediately distinguish it from the many other list_* siblings (list_posts, list_drafts, list_assets) because it is explicitly about uploaded media files.

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?

The description gives clear usage context by stating the returned URLs are 'usable directly in schedule_post's media_urls', which effectively routes the agent toward the downstream tool that consumes this output. It stops short of an explicit when-not or a named alternative for other media-fetching needs.

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