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

Annotations already declare readOnly, idempotent and non-destructive, so the safety profile is covered; the description adds value beyond that by flagging the resource as 'private' (capability-gated) and by disclosing that payment, per-card production and mailing are tracked as distinct states. That state-model note is real context an agent would otherwise have to discover from the output.

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 front-loaded with the operation and its required inputs, and the state-model caveat placed last. Nothing is wasted.

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?

An output schema exists, so return-shape explanation is not required, and annotations cover the safety profile; what remains is the state-model hint, which the description supplies. The one gap is that the undocumented order_id parameter is clarified only obliquely via the word 'parent'.

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 coverage is only 50% — order_id has no description at all — so the description compensates by calling it the 'parent' order_id, signaling that card-level identifiers are distinct entities under it. The token's secrecy requirement is already documented in the schema, so that part is repetition rather than added value.

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 (read a private purchase plus its order.cards), which no sibling does — cancel_order and prepare_order mutate, search_cards queries a different resource. It stops short of naming any sibling explicitly, so the differentiation is inferred rather than declared.

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 mention of 'using the parent order_id and order_access_token' implies the required credentialing path, but there is no statement of when to reach for this tool versus alternatives, nor any exclusion (e.g., use search_cards to find an order first). Usage is implied, not guided.

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