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

Annotations already establish read-only and non-destructive behavior. The description adds meaningful behavioral detail beyond that: seeded randomness, same seed + same day reproducibility, anonymous draw behavior, and the returned content shape. This is useful context for an AI agent deciding whether to call the tool.

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 organized with the core purpose first, then determinism, then usage examples, then return details. The 'Great for tarot apps...' sentence is slightly promotional but still helps an agent identify likely use cases, so no sentence feels wasted.

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 optional-parameter read endpoint, the description covers the core behavioral model, return content, seed reproducibility, and language/date flexibility is present in the schema. The only omission is an explicit note about how this choice compares to post_tarot_draw, but that is a minor gap given the overall 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?

Schema description coverage is 100%, so the parameters are already well documented. The description re-emphasizes the seed semantics and result shape, but adds only modest conceptual context beyond the schema. 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 the tool's function: returning a single tarot card for daily guidance, which distinguishes it from the multi-card spread endpoints. It is specific about the resource and behavior without naming a sibling explicitly, so it stops just short of a perfect score.

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 clear context for when this fits: 'Card of the Day' features, morning ritual apps, journaling tools, and daily reflection. It does not explicitly compare itself to post_tarot_draw or add 'use X instead' guidance, so it lacks full alternative routing.

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