Карты

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

Annotations already declare read-only, idempotent, open-world, and non-destructive behavior. The description adds valuable behavioral context: it returns cards from all accounts, marks externally-linked cards, and explains why ucid-related features fail for external cards.

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 compact sentences contain the full scope, the key output fields, downstream tool mappings, and the external-car exception. Every clause earns its place with no redundancy.

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?

Given zero input parameters, a rich annotations set, and an output schema, the description is complete. It explains the most important behavioral edge case (external cards lacking ucid) and would allow an agent to call the tool correctly without any 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?

The tool has zero parameters and the input schema is empty, so there is nothing to document. The description still adds semantic value by explaining what each output field (id, ucid) is for and how external cards are represented, exceeding the baseline for a zero-parameter tool.

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 clearly states 'All cards across all accounts' and specifies exactly what the tool returns: id, ucid, balance, type. It distinguishes itself from list_accounts and list_operations by focusing on cards, including the external-bank card caveat.

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 gives strong usage guidance by explaining that id is for card_operations and ucid is for card_limits/card_requisites, including the important exclusion that external cards have no ucid so those tools won't work for them. It does not explicitly say 'use this when you need a full card overview,' but that context is clearly implied.

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