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

Annotations already cover readOnly/idempotent/non-destructive, and 'Changes nothing' merely restates them, but the description adds a genuinely non-obvious behavioral caveat: recent posted statuses are only returned 'when WhatsApp has them loaded.' That conditional result-set behavior is not derivable from annotations or schema and is the main reason this scores above baseline.

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 and returned-field list are front-loaded, and the examples are compact and directly actionable. 'Changes nothing' is a small redundancy against the readOnlyHint annotation, and the parenthetical field list plus the 'when WhatsApp has them loaded' clause make the opening sentence slightly dense.

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 an output schema present, the description needn't explain return shapes, and annotations carry the safety profile; what it does supply is scope, the conditional availability of recent statuses, and filter examples. Remaining gaps are minor: no mention of target_session routing in prose and no ordering/pagination hints for the combined result set.

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 the enum values plus the default ('pending' = waiting, missed or failed) are already documented in the schema. The examples reinforce the filter semantics in practice but add little beyond it, and target_session is untouched by the description, so baseline 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 uses a specific verb and resource ('List the user's scheduled WhatsApp Status posts') and enumerates the returned fields (id, type, state, time, text/caption), plus a second source of results (recently posted statuses). It is clearly a read/list tool versus manage_status in the sibling set, though it never names that sibling to draw the boundary explicitly.

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 two examples give concrete invocation contexts — empty object for pending posts, filter: "all" for everything — so an agent knows which call shape to reach for. What is missing is any statement of when to prefer this over manage_status or get_scheduled_message; the guidance is contextual rather than exclusive.

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