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

No annotations are provided, so the description carries the burden. It discloses that the tool returns meaning details (upright/reversed, arcanum, suit, links) and that it looks up by slug or Russian name. However, it doesn't mention error behavior for invalid slugs/names, whether it returns both upright and reversed always, or any other behavioral traits. It's adequate but not rich.

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, front-loaded with the core meaning, then lookup details. Every word earns its place. The examples in the description are useful and compact.

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 single-parameter lookup tool with no output schema, the description covers the input format and the scope of the returned meaning. It doesn't describe the exact output structure, but with no output schema and a simple lookup, this is a minor gap. The tool is simple enough that the description is nearly complete.

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 100%, so the schema already documents the 'card' parameter with examples. The description adds the format details (slug pattern like major-00, cups-07) and Russian name examples, which slightly extends the schema. Baseline 3 is appropriate since the schema does the heavy lifting.

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 the tool's function: it provides the meaning of a single Rider-Waite tarot card, including upright/reversed, arcanum, suit, and links. It also specifies the lookup methods (slug or Russian name), which distinguishes it from sibling tools like tarot_draw or tarot_deck.

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 implies when to use this tool: when you need the meaning of a single card, and it explicitly mentions lookup by slug or Russian name. It doesn't explicitly state when not to use it or name alternatives, but the context of siblings (tarot_draw for draws, tarot_deck for deck info) makes the usage fairly clear.

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