get_card_performance

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

Annotations already declare readOnlyHint=true. The description adds the premium-gating and API key requirement, which is important behavioral context beyond read-only status. It does not disclose return format, pagination, or error behavior, limiting the added value.

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 description is three sentences, each serving a distinct purpose: purpose, default, and access requirements. It is front-loaded with the most important information and contains no superfluous words.

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 tool with two simple parameters and no output schema, the description covers the purpose, defaults, and access restrictions. It is mostly complete, though it could mention the structure of the return value (e.g., list of cards with P&L) for full completeness.

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 input schema has 0% description coverage. The description provides default values for both parameters (type=best, limit=10), adding some meaning. It does not explain the semantics of 'P&L' or what 'performance' entails, so the added value is minimal.

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 specifies the verb 'get', the resource 'cards performance by P&L', and the scope (best or worst, default top 10). It distinguishes itself from siblings like get_card (individual card details) and get_card_prices (price data) by focusing on performance ranking.

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 states the default behavior and access restrictions (premium-gated, requires API key), giving clear context for when to use. However, it does not explicitly mention when not to use or suggest alternatives among the many card-related sibling tools.

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