Send contact cards

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

Annotations already declare readOnlyHint=false, openWorldHint=true, idempotentHint=false and destructiveHint=false, so the safety profile is covered. The description adds only the 'up to 20' cardinality, which merely restates the schema's maxItems; it says nothing about delivery failure behavior, permission requirements, or that sends are outward-facing to arbitrary recipients.

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?

A single front-loaded sentence with zero filler, and the cardinality constraint arrives immediately. It is efficient, though its brevity also reflects sparseness rather than deliberate polish.

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?

This is an outward-facing, irreversible send with 6 parameters and no output schema; the description covers only cardinality. Nothing tells the agent about failure modes, retry/idempotency strategy in prose, or recipient validation requirements, which is inadequate for a messaging tool of this complexity.

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 83%, with recipient formats, phone format, idempotency reuse semantics and replyToMessageId quirks all documented in the schema itself. The description contributes no additional parameter meaning, so 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?

States a specific verb (Send) and resource (contact card) plus the cardinality limit, which separates it from send_text, send_media, send_location and send_poll by payload type. It does not explicitly name a sibling or state how it differs beyond the resource noun, so it stops short of 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?

No when-to-use guidance, no prerequisites (e.g. account must already chat with the recipient), and no alternatives named against the crowded sibling set of send_* tools. Usage is only inferable from the tool name.

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