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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds useful context about the returned metrics but does not disclose behavioral details such as how 'top posts' are ranked, whether limits apply, or how the window affects the top-post selection.

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?

The description is a compact single sentence that enumerates the key output categories without redundancy. It is efficient, though the informal opener 'How the posts did:' is slightly less direct than a more explicit 'Returns post performance metrics' would be.

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 one optional parameter, full schema coverage, read-only/idempotent annotations, and an output schema, this is a fairly complete definition for a simple analytics tool. The main missing pieces are sibling differentiation and definition of 'top posts,' but those are not critical given the output schema and 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?

The only parameter, window, is already fully described in the input schema ('7d, 30d or 90d'), so schema coverage is 100%. The description adds no additional meaning for this parameter, so the baseline score of 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?

The description clearly states that the tool reports post performance via totals (impressions, engagement, replies, engagement rate) and top posts by views, likes, and replies. It is clear about the resource and outcome, though it does not explicitly distinguish itself from sibling tools like list_posts or get_run beyond the metric vocabulary.

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?

There is no guidance about when to use this tool versus alternatives such as list_posts or get_account. It neither provides usage conditions nor mentions which sibling tool to choose for other post-related needs.

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