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

Annotations already establish that this is a safe read, and the description goes well beyond them: it discloses that Facebook lacks impressions/reach, that Facebook story metrics are unavailable, that Instagram story metrics exist only during the 24-hour live window with no backfill, and that sub-5-viewer stories return story_insights_withheld. These are exactly the non-obvious behaviors an agent needs; only rate limits/response shape are unaddressed.

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 purpose is front-loaded in the first clause, followed by tightly packed platform caveats with no filler. Every sentence carries distinct, actionable information about metric availability.

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?

The description is thorough on platform-specific metric quirks, which is the main complexity here, and no output schema exists so some return-shape explanation is expected. However, it never describes the general response structure (e.g. per-post list shape) for the common non-story, non-Facebook cases, leaving an agent to infer it.

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% with a single well-described 'id' (launch UUID) parameter, so the schema already carries the semantics. The description adds nothing about the id, which is acceptable given the high coverage but earns no bonus.

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 opens with a specific verb+resource ('get publishing analytics with per-post engagement metrics') and enumerates the metric types, so the purpose is unmistakable. It does not differentiate itself from the sibling get_batch_launch_analytics, which is the only thing keeping it from 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?

There is no when-to-use or when-not-to-use guidance, no mention of prerequisites (e.g. launch must be published), and no routing toward alternatives such as the batch variant. The platform caveats describe output behavior, not invocation conditions.

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