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

Goes well beyond the annotations: every call creates a new draft with a new link (non-idempotent behavior made concrete), up to 500 recipients per draft, one card per household, no photo capture, and how photo cards are handled. It also discloses the senderName default (unsigned message) that affects the saved artifact.

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 core purpose and the no-mail/no-charge guardrail are front-loaded, and nearly every sentence carries a distinct rule. It is a dense single paragraph though, and the photo-handling tail could be tighter or bulleted without losing 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 non-idempotent creation tool with no output schema, the description covers what matters: the returned link, the 500-recipient cap, per-household semantics, placeholder behavior, and photo limitations. An agent can call it correctly without further 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?

With 80% schema coverage the baseline is 3, but the description adds real meaning the schema lacks: the recipient address format ("Street, City, ST ZIP", empty if unknown), giftName as a short noun phrase without the store name, name as it appears on the card, and the no-senderName default. It does not add much on the design or occasion params beyond pointing at list_card_designs.

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 (save a DRAFT of postcards) plus the full scope from a single card to a whole guest list, and explicitly says what it does not do (never mails, never charges). It also points to list_card_designs for design ids, which separates it from that sibling.

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?

Gives clear context: use it to produce a draft link the sender later opens to add a return address, review, and pay, and it explicitly rules out mailing and charging. It names list_card_designs as the source for designs and occasions, but never mentions quote_price, leaving the pricing alternative implicit.

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