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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the safe read-only nature is established. The description adds that this is a catalog view with no paid content, clarifying the scope boundary. This is useful but doesn't go much beyond what annotations provide; it doesn't get into rate limits, auth, or failure modes.

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: the first lists what's included, the second clarifies what's not. Concise and front-loaded with the core purpose. Could be slightly tightened but overall efficient.

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 simple, read-only listing tool with no required parameters, a short description suffices. The description explains the catalog contents and explicitly notes that detailed interpretations are a paid feature elsewhere. This covers the main use case without needing more elaboration.

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 100%, so both parameters are documented in the schema. The description mentions filtering by theme implicitly ('о чём расклад') and the query parameter examples ('любовь', 'работа', 'год') are in the schema. The description itself doesn't add parameter details beyond the schema, so baseline 3 is appropriate.

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 this lists Tarot spreads with title, card count, theme, and page URL. It distinguishes this as a catalog-listing operation. However, it doesn't explicitly differentiate itself from sibling tools like get_card_meaning or list_decks, though the resource types differ.

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 a catalog-browsing use case and explicitly states what's NOT included (position breakdowns and card interpretations are paid). It doesn't name alternatives like list_decks or get_card_meaning, so usage guidance is implied rather than explicit.

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