Subscribe to a WhatsApp contact's online and typing presence so updates arrive later as event-stream notifications; returns only a success confirmation.
Subscribe to a contact's presence (online, typing) so it arrives as presence events. It does not return presence: the updates come later through the event stream. Returns a success confirmation.
| Name | Required | Description | Default |
|---|---|---|---|
| chatId | Yes | Chat JID |
Changes observed during successful MCP inspections.
v2.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations declare a non-destructive, idempotent, open-world write, so safety is already covered. The description adds genuinely useful non-obvious behavior: the call does not return presence data, updates are delivered later via the event stream, and the immediate return is only a success confirmation. That closes the biggest agent confusion for a subscribe-style tool.
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 short sentences, front-loaded with the action, then the crucial negative ('It does not return presence') and the return behavior. No filler and nothing buried.
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?
No output schema exists, so the description carries the return-value burden and does so ('Returns a success confirmation') while explaining the async delivery path. For a single-parameter subscription tool, nothing an agent needs to invoke it correctly 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?
There is only one parameter (chatId) and the schema documents it at 100% coverage as the 'Chat JID'. The description mentions subscribing to 'a contact's presence' but adds no format or naming details beyond what the schema already provides, so this sits at the baseline for a fully documented 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?
States a specific verb+resource ('Subscribe to a contact's presence') and enumerates the presence types (online, typing), so an agent can distinguish it from the mutation-oriented sibling whatsapp_set_chat_presence. It stops short of naming the sibling explicitly, so a 4 rather than a 5.
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?
Usage is implied rather than stated: the agent learns updates arrive asynchronously and that this tool does not return presence, which implies 'call this, then listen to the event stream.' There is no explicit when-to-use/when-not guidance relative to alternatives such as whatsapp_set_chat_presence.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.