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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds the transport endpoint and a concrete cost (10 credits, Tier 1), which is genuinely useful billing context, but says nothing about whether the draw is randomized, whether the seed makes it reproducible, or how reversals 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 single descriptive sentence is front-loaded and waste-free, but the bracketed group/endpoint/cost block is scaffolding shared across hundreds of sibling tools rather than information unique to this definition. Terse to the point of being under-specified.

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 values need not be explained, and annotations cover the safety profile. However, with six optional parameters and no required fields, the description leaves the agent guessing about what a caller should supply and when, which is a meaningful omission for a drawing tool.

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 only 50%: `seed`, `question`, and `allowReversed` carry no schema documentation, and the description does not compensate for any of them. For a divination tool, the absence of any note on `question` or `allowReversed` (which defaults to true and changes the result set) is a real gap.

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 and resource: a single-card draw from the Marseille deck. It is clear enough to distinguish from multi-card spreads like draw_three_card or draw_celtic_cross, but it never contrasts itself with near-neighbors such as marseille_daily, marseille_birth_card, or marseille_clarify, which may also produce single-card output.

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 guidance on when to use a single-card draw rather than any other Marseille spread, no mention of prerequisites, and no named alternative. The bracketed endpoint and cost tags are metadata, not usage direction.

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