Marseille: Custom Spread

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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds genuinely new behavioral context: cards are seeded the same way as fixed spreads (implying reproducibility via the seed parameter) and each call costs 10 credits (Tier 1), which an agent should know before invoking.

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 core sentence is front-loaded and waste-free, and the bracketed metadata lines are compact. The group line repeats what the tool name already conveys ('Marseille'), a minor redundancy, while the cost and endpoint lines earn their place.

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 no explanation, and the positions/count alternation is addressed. But with zero required parameters, the default behavior when neither positions nor count is supplied is unstated, which is a meaningful gap for a 6-parameter 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 coverage is only 50%, so the description must carry weight, and it does: it clarifies that positions and count are alternative ways to specify the spread and reiterates the 1-15 bound. It doesn't cover seed, question, art, or allowReversed, but the mutual-alternative relationship between positions and count is real meaning beyond the schema.

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 gives a specific verb and resource ('Draw 1-15 Marseille cards') plus the distinguishing scope ('into positions you name or by count'), which separates it from the fixed-spread siblings such as draw_celtic_cross. It stops short of naming a sibling explicitly, so it's clear but not maximally differentiated.

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?

Usage is implied through the 'positions you name or by count' framing and the 'seeded like the fixed spreads' contrast, which hints that standard spreads live elsewhere. However, it never states when to prefer this over a named spread, nor any exclusions or prerequisite conditions.

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