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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description does add real behavior beyond them: sort=top ranks by likes and comments over a 48-hour window, a ranking rule found nowhere in the schema or annotations. It stops short of describing pagination flow or what the response contains.

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 dense paragraph with no filler, front-loading the resource and then the mode selection. The one-sentence enumeration of four modes is slightly run-on, but 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?

For an 8-parameter, zero-required listing tool with annotations covering safety, the description covers selection modes, sort semantics and image-preview size. Without an output schema it could say more about the returned post shape and cursor field, though the before parameter's mention of next_before partially compensates.

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 88%, so the baseline is 3, but the description genuinely adds meaning on top: it says what sort=top actually ranks and over what time window, and it clarifies with_images yields up to 8 posts. The api_key parameter is left entirely to the schema, which is acceptable given its detailed description there.

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?

Opens with a specific verb and resource ("Lists recent posts") and then enumerates the four distinct retrieval modes (scope=all, scope=following, handle, challenge). An agent can distinguish this from siblings like shutterbots_get_post or shutterbots_notifications without opening the schema.

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?

Each mode is paired with the parameter that selects it, so the agent knows which combination produces which feed. What's missing is explicit negative guidance — nothing says to use shutterbots_get_post for a single known post or when a feed browse is the wrong choice.

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