Forward a WhatsApp message

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

The annotations already capture readOnlyHint=false, idempotentHint=false, and destructiveHint=false. The description adds the meaningful behavioral fact that the recipient sees the message marked as forwarded, which an agent cannot infer from the schema or annotation flags. It also implies the original message remains untouched.

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 sentences, both earning their place. The first states the core action, and the second conveys a notable user-facing behavior. There is no repetition of schema details, no filler, and the key object and destination are front-loaded.

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 two-required-parameter operation without an output schema, the description adequately covers the action, the destination chat, and the primary observable outcome ('marked as forwarded'). A slightly more complete description might mention what happens on success or that only chat ID and message ID are needed, but nothing critical appears 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?

Both parameters are already fully documented in the JSON schema with high specificity: message_id gets an explanation of its origin and an example, and to_chat_id gets a clear 'Destination chat' label. Since schema description coverage is 100%, the description bears no additional parameter burden, and the baseline 3 applies.

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 uses a specific action verb ('Forward') a clear resource ('an existing message') and a target ('another chat'). The detail that the recipient sees it marked as forwarded is a distinctive behavior that differentiates it from siblings like send_message and edit_message, even though no sibling is named.

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 does not explicitly tell an agent when to choose this over alternatives, nor does it name send_message or edit_message as alternatives. It implies usage by stating it applies to 'existing messages', and the schema's message_id description references read_messages / search_messages, but that guidance is in the schema, not the main description.

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