mcp-whatsapp

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

Annotations provide critical behavioral hints: destructiveHint=true (modifies data), readOnlyHint=false (not read-only), idempotentHint=false (non-idempotent), openWorldHint=true (handles dynamic resources). The description adds minimal context beyond this—it implies mutation but doesn't detail side effects (e.g., notifications to recipients, edit history), rate limits, or authentication needs. It doesn't contradict annotations, so no penalty, but offers little supplemental behavioral insight.

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 a single, front-loaded sentence: 'Edit a previously-sent message.' It wastes no words, directly conveying the core action without fluff. Every word earns its place, making it highly efficient for an AI agent to parse quickly.

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 (destructive mutation with 3 required parameters) and rich annotations, the description is minimally adequate. Annotations cover safety and idempotency, and the schema documents parameters well. However, no output schema exists, and the description doesn't explain return values or error conditions. It meets a basic threshold but lacks depth for a mutation tool in a messaging context.

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%, with clear parameter descriptions: 'chat_jid' (WhatsApp JID format), 'message_id' (WhatsApp message ID), 'new_body' (replacement text). The description adds no additional semantic context beyond the schema—it doesn't explain parameter relationships (e.g., message_id must belong to chat_jid) or constraints (e.g., edit time limits). With high schema coverage, baseline 3 is appropriate as the description doesn't compensate with extra meaning.

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 'Edit a previously-sent message' clearly states the verb ('Edit') and resource ('previously-sent message'), making the purpose immediately understandable. It distinguishes from siblings like 'send_message' (creation) and 'delete_message' (removal), though it doesn't explicitly name these alternatives. The description is specific about the action but could be more precise about the platform context.

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 provides no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., needing an existing message), exclusions (e.g., cannot edit messages in certain states), or compare with siblings like 'send_reply' or 'delete_message'. The agent must infer usage from the tool name and schema alone.

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