messages_send_contact

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

Annotations already declare readOnlyHint=false, openWorldHint=true and destructiveHint=true, so the safety profile is covered structurally. The description adds that the action 'reaches other people on the platform' and requires user confirmation, which is useful context beyond the annotations, but the 'deletes, or redirects data' clause is confusing and does not map to sending a vCard.

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 verb+resource is correctly front-loaded, and the endpoint/transport parenthetical is compact. However, the middle sentence is a muddled template fragment that mixes unrelated concerns (reaching others, deleting, redirecting), hurting clarity.

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 an open-world, destructive mutation tool with no output schema and 0% parameter documentation, the description is too thin. It should explain the addressing model and the required contact object, and clarify what confirmation is needed, none of which it does.

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% across 8 parameters, and the description explains none of them. Details such as the required nested contact object (displayName + vcard), the addressing options (chatId/username/phoneNumber), or replyToMessageId are left entirely to inference from examples, so the description fails to compensate for the coverage gap.

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 and resource: 'Send a contact card (vCard)'. This clearly distinguishes it from sibling send tools like messages_send_media or messages_send_location by the payload type. It does not explicitly name an alternative, but an agent can tell what it does at a glance.

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?

There is no clear when-to-use guidance, no alternatives named among the many messages_send_* siblings, and no prerequisites. The second sentence ('get the user's confirmation first') is a generic caution rather than routing guidance, and it is tangled with an unrelated clause about deleting/redirecting data.

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