list_newsletters

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

With no annotations, the description carries the behavioral burden. It communicates that names are 'live' when possible and that it 'falls back to cache when offline,' which is meaningful runtime behavior. It does not detail empty-cache behavior or staleness, but for a read-only listing tool this is adequate.

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?

Two short sentences with no filler. The core purpose is front-loaded, and the cache fallback is a separate second sentence that earns its place.

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?

For a simple optional-parameter tool with no annotations or output schema, the description covers the main behaviors an agent needs: what is listed and how the tool behaves offline. It could add a note on output shape or fresh-vs-cache indication, but nothing critical is missing.

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 only parameter, limit, is not mentioned in the description, and schema description coverage is 0%; the description does not compensate for this gap. The schema itself does provide min/max/default, so this is not harmful, but the description adds no semantic value for the parameter.

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 an explicit verb ('List') and a distinct resource ('followed WhatsApp channels (newsletters)'), then adds the differentiator 'with live names.' This makes it easy to tell apart from siblings like list_chats, list_groups, and newsletter_metadata.

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 implies when to use it (needing followed newsletters, including when offline thanks to cache fallback), but it never explicitly says when to prefer this over sibling tools such as newsletter_metadata or list_chats, nor does it state any exclusions.

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