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

Annotations already declare readOnlyHint=true and openWorldHint=false, which covers the safety profile. The description adds that it returns 'slugs the other tools take,' which is useful behavioral context about its output purpose. However, it doesn't disclose the return format, result count limits, or behavior on no-match queries. With annotations covering the read-only safety, a 3 is appropriate.

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 concise sentences with zero filler. The first states the core action and output, the second gives crisp usage direction. Well front-loaded and to the point.

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 search/lookup tool with full schema parameter coverage, read-only annotations, and only 2 params, the description is complete. It explains what it does, what it returns (slugs for other tools), and when to use it. The absence of an output schema is compensated by the clear statement that it returns matching cards with slugs, which is sufficient for an agent to proceed.

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% — both parameters (query, language) have descriptions in the schema itself. The description adds 'part of a card name in any supported language' context for the query parameter and explains that the search is partial-match ('part of a card name'), which adds modest value beyond the schema. Baseline 3 is correct here as the description offers some extra nuance but the schema already 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 states a specific verb+resource ('Search the 78-card Rider–Waite–Smith deck by name') and clearly distinguishes its purpose from the sibling tools (get_love_question_answer, get_tarot_card_love_meaning) by noting it 'return[s] matching cards with the slugs the other tools take.' This positions it as the lookup/bridge tool that precedes others.

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 explicit when-to-use guidance: 'Use this first when you only have a card name.' This clearly indicates it's the entry-point tool when only a name is known, contrasting with the sibling tools which consume the slugs it produces. This is strong, actionable usage direction.

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