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

Annotations already declare readOnly/idempotent/non-destructive, so the burden is lower. The description still adds real behavior: results are sorted by date when a range is given, the default cap is 50 posts, and per-network results are deliberately omitted. It does not discuss pagination beyond the limit or response shape, so it stops short of a 5.

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 sentences, each earning its place: what it returns, how to filter, and how to route around it. The defaults and the schedule_post workflow rule are front-loaded with no filler.

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 listing tool with no output schema, the description supplies everything an agent needs: filter modes, default limit, ordering, and sibling routing to get_post for per-post details. Safety is already covered by annotations.

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%, so baseline is 3, but the description adds value the schema does not: date-range reads are sorted by date, an empty argument set defaults to the 50 most recent, and status filtering is the third mode. It does not spell out the enum values beyond what the schema lists.

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 ('Lists') and resource ('posts') plus what each row contains (status, date, targets). It is clearly distinct from get_post, which it explicitly names as the per-post alternative.

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 explicit invocation modes (from/to range, status filter, or nothing for the 50 most recent), a workflow rule ('read before schedule_post to avoid duplicates and slots too close together'), and an exclusion routing to get_post. When and when-not are both covered.

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