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

With annotations only asserting readOnlyHint and openWorldHint, the description carries the real behavioral burden and delivers: it warns that samples counts indicate thin evidence, that topPosts are grouped and ranked only within platform, that relativeToPlatformBest never compares across platforms, and that Instagram contributes different metrics depending on insights permission while Threads/Facebook produce none. This is rich, non-obvious disclosure beyond the structured fields.

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?

It is a single dense paragraph rather than a front-loaded structure with bullets, but essentially every sentence carries functional interpretation guidance and nothing reads as filler. Slightly more scannable formatting would push this higher.

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?

There is no output schema, so the description must explain return values, and it does so thoroughly: field names (samples, coverage, topPosts, relativeToPlatformBest), their semantics, and platform-specific caveats. An agent has what it needs to call and interpret this correctly.

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 description coverage is 100% (days and profile_ids are both documented in the schema), and the description adds no parameter detail beyond it. Baseline 3 applies when the schema does the heavy lifting.

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: how the user's published posts performed, enumerating the concrete outputs (views, engagement, period-on-period change, best posting hour/weekday/category, top posts). This is clearly distinguishable from siblings like get_account_summary. An agent can tell what this returns 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?

Strong interpretive guidance: quote raw totals behind percentages, read `coverage` before comparing platforms, never rank platforms on a metric one lacks. However, it does not explicitly state when to reach for this tool over siblings like get_account_summary or list_scheduled_posts, so the when/when-not routing is implied rather than named.

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