Best time to publish

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

Annotations already declare read-only, idempotent, non-destructive, so the bar is lower. The description still earns credit for disclosing methodology ('each post scored against your median, so one viral post does not decide') and for warning that follower-online data is conditional on Meta providing it. It does not state the lookback window or what happens with sparse data.

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 front-loaded sentence with no filler; the qualifying parenthetical is the most useful part. The nested clause about follower data makes it slightly dense but nothing is wasted.

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 no output schema and 40% parameter coverage, the description should explain the result shape more explicitly, e.g., a ranked list of weekday/time blocks with scores. It conveys the grain but not the return structure or how metric choice affects results, leaving gaps for a 5-param analytic tool.

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 40%, so the description must carry weight. It clarifies the time zone meaning ('in your time zone') and the output granularity, but adds nothing about the three undocumented parameters: the FEED/REELS type, the posts count window, or the metric enum semantics.

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/resource pairing: it reports when your own posts performed best, broken down by weekday and 3-hour block. The parenthetical about median-scoring makes the output unit concrete. It does not name the sibling insight tools it differs from (get_account_insights, get_audience), so it stops short of a 5.

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?

Usage is only implied: the 'your own posts' framing hints this is a self-performance tool rather than a follower-activity tool, but there is no explicit when-to-use, when-not-to-use, or named alternative. An agent must infer that this is the scheduling/optimization tool rather than a general insights tool.

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