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 the pricing behavior ('[Cost: 10 credits (Tier 1)]'), which is genuinely useful context not present in structured fields, but says nothing about the draw semantics (card selection, reversals, seeding) beyond the layout.

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 short lines, layout stated first, metadata tags after. Nothing is wasted, though the sparse content borders on under-specification rather than disciplined brevity.

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, but for a priced draw tool with five parameters (three undocumented), the description omits how the question and seed affect the draw and how reversed cards are handled, leaving an agent under-informed.

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 40% — seed, question and allowReversed have no schema descriptions. The 500-char question cap, integer seed bounds, and default-reversed behavior are undocumented in both schema and description, so the description fails to compensate for the 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 names a specific spread layout ('Past / Present / Future three-card spread'), which tells an agent exactly what divination result to expect. It does not distinguish itself from sibling Marseille spreads like seven_card, celtic_cross, or cross, so an agent must infer the difference from the tool name alone.

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 choose this three-card spread over the many sibling spreads (single, seven_card, celtic_cross, career, love, decision). The only routing signal is the group tag '[Group: Tarot: Marseille]'. No prerequisites or exclusions are stated.

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