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

Annotations already declare a safe, read-only, idempotent, non-open-world operation, so the bar is lower. The description adds genuine value beyond them: an admin-only permission requirement and a feature-flag dependency, which an agent cannot infer from the annotations.

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?

Three tight sentences, front-loaded with the core action, followed by scope, then constraints. Bold formatting highlights the two gating requirements. No wasted text.

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?

Simple read-only list tool: annotations cover the safety profile, the param schema is fully documented, and the description describes what each record conveys (inbox connection, lead delivery status) in lieu of an output schema. Auth and feature constraints are stated. Minor gap: no mention of result volume, ordering, or empty-state behavior.

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% and only one optional `fields` parameter exists, with its enum documented in the schema. The description adds no syntax or format detail for it, so the baseline 3 is appropriate.

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?

Starts with a specific verb+resource ("List connected Facebook Pages") and clarifies scope beyond the title: pages connected as a Messenger inbox, plus whether each delivers Lead Ads leads. This distinguishes it from nearby siblings like list_facebook_leads and list_facebook_lead_forms without needing 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?

The description gives real prerequisites (administrators only, `facebook_marketing` feature required) that gate usage, but never states when to prefer this over list_facebook_lead_forms, list_facebook_ad_accounts, or list_inboxes. Usage context is implied rather than routed.

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