Facebook brand page insights

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

Annotations already declare readOnlyHint=true, and the description adds valuable behavioral disclosures: detailed error handling for 429 and 401, the structuredContent.errorCode and retryable fields, and the behavior of comparison fields (priorValue, delta, deltaPercent). This goes well beyond the annotation and gives the agent concrete expectations for edge cases.

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 well-structured with clear sections for comparison options and error handling. It is concise, front-loaded with the core purpose, and every sentence adds value. No fluff or repetition of schema basics beyond necessary context.

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?

Given the presence of an output schema and readOnly annotation, the description covers all essential aspects: what the tool does, how aggregation works, comparison mechanics, and error handling. It is complete enough for an agent to invoke the tool confidently and interpret the result even before seeing the output schema.

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 input schema already has 100% coverage with descriptions for all five parameters, so the baseline is 3. The description adds important semantic value by explaining what 'compare_with' actually does (MoM/QoQ vs YoY), including the effect on output metrics (flat comparison fields). It also clarifies response_format token-efficiency, enriching the schema definitions.

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 and resource: 'Fetch Facebook metrics for all brand pages.' It clearly differentiates from sibling tools by specifying 'all brand pages' (as opposed to perhaps a single page). The scope is unambiguous and the mention of aggregation and comparison further clarifies the tool's purpose.

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?

The description provides clear usage context by explaining supported aggregation types and comparison periods, but it does not explicitly mention when to use this tool over its sibling tools (e.g., pinmeto_get_facebook_insights). It could improve by stating 'for a single brand page, use pinmeto_get_facebook_insights' or similar. Still, the context is clear enough that an agent can infer applicability.

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