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

The readOnlyHint=true annotation already declares this a safe read operation, so the bar is lower. The description usefully indicates the output is markdown and enumerates the exact content dimensions returned, which adds behavioral context beyond the annotation. It doesn't describe pagination or size limits, but for a single-card lookup these aren't material.

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 dense sentences with zero waste. The first sentence enumerates all content dimensions, the second states the output format (markdown). Every element earns its place and important facts are front-loaded.

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?

This is a straightforward read-only lookup tool with 100% schema coverage, readOnlyHint annotation, and no output schema needed. The description fully enumerates what content the response covers (upright, reversed, feelings, ex, yes/no, element) plus output format. Nothing essential is missing for an agent to use this correctly.

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 (slug and language) are fully documented in the schema. The description adds value by stating slug should always be the English slug, which supplements the schema. Beyond that, schema already handles the heavy lifting, 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 states a specific verb+resource: what a single tarot card means for love and relationships. It enumerates the specific dimensions covered (upright, reversed, feelings, ex context, yes/no leaning, element), clearly distinguishing this from sibling tools like get_love_question_answer and search_tarot_cards. The scope is precise and leaves no ambiguity about what it returns.

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 the tool is for looking up love-related meanings of a specific card, which differs from the sibling tools (get_love_question_answer for question answering, search_tarot_cards for searching). However, it does not explicitly state when to use this tool vs the alternatives, nor note any prerequisites or exclusions.

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