learnRead this guide first to understand tool IDs, account handling, workflows, message shape, and error-code fixes before using the WhatsApp tools.
The guide to these tools: ids, account_id with several accounts, the workflows, the message shape and what to do about each error code. Read it once, before the other tools; it never touches WhatsApp.
| Name | Required | Description | Default |
|---|---|---|---|
| account_id | No |
Changes observed during successful MCP inspections.
v1.6.0Input schema / properties / account_id / descriptionRemoved value: -"Account id"v1.0.3Input schema / properties / account_id / descriptionPrevious value: -"Registry account id (default, work, …). Omit to resolve from chat_id or message_id, or the default account."New value: +"Account id"v0.15.0Input schema / additionalPropertiesAdded value: +falseInput schema / properties / account_idAdded value: +{
+ "description": "Registry account id (default, work, …). Omit to resolve from chat_id or message_id, or the default account.",
+ "minLength": 1,
+ "type": "string"
+}v0.9.3Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover readOnly/idempotent/non-destructive/closed-world, and the description adds the meaningful behavioral point that the call has zero effect on the WhatsApp account itself. It also signals the content categories (ids, workflows, error codes), which is useful for judging whether to call it first, though it doesn't specify the response shape or size.
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?
One dense sentence that front-loads the topics covered and ends with the strongest routing cue ('read it once, before the other tools'). No filler and every clause carries information.
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 single-optional-parameter documentation tool with no output schema, the description supplies everything needed: what the guide contains, the account scoping rule, the recommended call order, and confirmation of no side effects.
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 coverage is 0% — account_id is an unexplained bare string — and the description compensates by explaining that account_id matters when several accounts are in play. It does not clarify when the parameter can be omitted despite being optional, which keeps it short of a 5.
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?
A specific resource is named — a guide covering ids, account_id semantics for multi-account setups, workflows, message shape, and error codes — and 'it never touches WhatsApp' immediately distinguishes it from every action sibling. An agent can tell this is documentation retrieval, not an API call, without opening the schema.
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?
'Read it once, before the other tools' gives explicit ordering guidance relative to the 22 sibling tools, and the exclusion ('never touches WhatsApp') tells the agent not to expect any live data or side effects. Both when-to-use and what-it-is-not are stated.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.