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

Annotations already declare the full safety profile (readOnly, idempotent, non-destructive, closed-world). The description adds valuable context beyond that — it reads from cache with no network, and notes get_group forces a fresh GroupMetadata.update, which explains staleness behavior the annotations don't.

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?

Purpose is front-loaded, immediately followed by the cache/no-network caveat and the alternative routing. The examples are compact and each demonstrates a distinct scenario with no filler.

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?

An output schema is present so return values needn't be explained, and annotations cover safety. Combined with cache-vs-live disclosure and param examples, an agent has everything needed to call it correctly; only pagination/ordering of results is left unspecified.

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%, so the baseline is 3, but the description goes further by showing each parameter in context (query substring match, limit as top-N). This directly illustrates intended usage of both optional params.

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?

States a specific verb ('List') and resource ('WhatsApp groups the user belongs to') with clear scope. It distinguishes itself from the sibling get_group by contrasting list-all behavior against a single-group live lookup.

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?

Explicitly names the alternative (get_group) and the condition that selects it ('For a live snapshot of a single group'). The three examples map concrete intents to inputs, removing ambiguity about when to use which parameter.

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