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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and closed-world scope, so the safety profile is covered. The description contributes non-schema operational context (cost of 10 credits, Tier 1, POST endpoint, group), but says nothing about draw behavior itself, such as whether seeding makes the draw reproducible or how reversed cards are handled.

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 definition is compact and front-loads the spread identity, with the endpoint/cost metadata in tagged lines that are easy to parse. There is no filler, though the brevity is partly under-specification rather than pure economy.

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?

An output schema exists, so return-value documentation is unnecessary, and the description does convey spread, deck style, and cost. However, for a 6-parameter draw tool surrounded by dozens of near-synonymous tarot draws, it omits the usage routing and the purpose of question/seed/allowReversed, leaving real gaps.

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 only 50% and the description contributes no parameter meaning at all. The undocumented parameters (seed, question, allowReversed) have no explanation anywhere, and the two schema descriptions that do exist (fields, precision) are recycled astrology text referencing planets.longitude and houses.cusp, which is actively confusing for a tarot draw tool. With low coverage the description is expected to compensate and does not.

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 names a specific spread ("Adapted 10-card Celtic Cross") and deck style ("Marseille pip-style reading"), which lets an agent distinguish it from the RWS and Lenormand Celtic Cross siblings and from other Marseille spreads like draw_cross or draw_seven_card. The verb is only implied by the tool name rather than stated, so it stops short of the level of explicit sibling differentiation seen in the best definitions.

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?

There is no when-to-use guidance, no exclusions, and no mention of alternatives among the many Marseille draw siblings (draw_cross, draw_seven_card, draw_three_card, draw_decision, draw_love, etc.). The agent must infer the choice purely from the spread name.

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