list_viber_chats

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

With no annotations, the description carries full behavioral burden. It discloses warnings (e.g., 'WARNING: only fields that exist on this endpoint work — do NOT use created or edited'), default values (sort_dir, skip, take), pagination limits, and automatic resolution of user names. It does not mention auth, rate limits, or return format, but since an output schema exists, that gap is acceptable. The warnings and defaults add substantial transparent context.

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 structured as a clear list of arguments, each with one line of explanation. It is slightly long due to 10 parameters, but every line adds value, including the warning about sort fields. The format is scannable and efficient.

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 tool's complexity (10 parameters, no annotations, no schema documentation), the description is highly complete. It covers all parameters, defaults, and warnings. It does not mention authentication or rate limits, but these are not typically required for a list operation and are absent from most sibling descriptions. The output schema provides return-value details, so the description does not need to.

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 0%, so the description must compensate. It does so thoroughly, explaining all 10 parameters with examples (e.g., queue '10333', contact ID format), constraints (direction IN/OUT, date format YYYY-MM-DD), and warnings (sort field limitations). This goes far beyond the schema, which only provides types and defaults.

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 begins with 'List Viber activities with channel-specific fields,' which uses a specific verb ('List') and resource ('Viber activities'). This clearly distinguishes it from sibling tools like get_viber_chat (which retrieves a single chat) and other channel-specific list tools (list_messenger_chats, list_whatsapp_chats).

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 tool's purpose is clear from the name and description, but it does not explicitly state when to use it over alternatives or mention exclusions (e.g., 'Use this instead of list_web_chats if you need Viber channels'). However, parameter guidance like 'Use list_queues to find names' and 'call list_contacts(search=...)' provides context on prerequisites. This is clear context but lacks explicit alternative comparisons, so a 4 is appropriate.

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