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 useful context beyond annotations — the endpoint (POST /v1/geomancy/rubeus) and a concrete cost of 10 credits (Tier 1) — but says nothing about what the response contains or any limits.

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 semantic line is front-loaded and the bracketed metadata (group, endpoint, cost) is compact and scannable with zero filler. It is arguably too sparse rather than bloated, but nothing is 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?

An output schema exists, so return values needn't be spelled out, and annotations cover safety. Still, for a zero-required-param divination endpoint in a large sibling family, the description leaves the core behavior (that it yields the Rubeus figure's reading) implicit and gives no selection criteria.

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% and both optional params (fields, precision) are fully documented in the schema with examples. The description adds no parameter detail, which is acceptable given the schema does the heavy lifting — baseline 3.

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 conveys the specific figure's symbolism ('Passion, anger, blood: ill omen') and the endpoint/group identify it as the Rubeus geomancy figure, distinguishing it from the other 15 geomancy siblings by name. However, it never states what the tool actually does or returns — no verb like 'returns' or 'retrieves' — so the purpose is only implied.

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 explanation of how to choose Rubeus over Acquisitio, Puella, or the other geomancy figures, and no prerequisites stated. The agent must infer everything from the figure's meaning alone.

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