astroway_geomancy_rubeusCalculate the Rubeus geomancy figure and retrieve its interpretation for passion, anger, blood, and ill-omen signals in a geomantic reading.
Passion, anger, blood: ill omen.
[Group: Geomancy (Agrippa)] [Endpoint: POST /v1/geomancy/rubeus] [Cost: 10 credits (Tier 1)]
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
| Name | Required | Description | Default |
|---|---|---|---|
| figure | No | ||
| source | No |
Changes observed during successful MCP inspections.
v1.6.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds genuinely useful metadata beyond that: the POST /v1/geomancy/rubeus endpoint and the 10-credit Tier 1 cost, which matters for call budgeting. It says nothing about the shape or depth of the returned entry, but an output schema exists, so that omission is tolerable.
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?
Very short and front-loaded: keyword meanings first, then bracketed group/endpoint/cost metadata. Every line carries information, though the opening is a bare keyword fragment rather than a sentence, which slightly reduces immediate comprehension.
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?
For a zero-argument reference lookup with an output schema, the description supplies the concept, the tradition, the endpoint and the credit cost. What is missing is any statement that this returns a static reference entry (and that it is not an AI interpretation), which is exactly the distinction an agent needs when choosing among the many divination siblings.
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?
The tool takes zero parameters, so the schema baseline of 4 applies and there is nothing for the description to disambiguate. The metadata lines correctly imply no arguments are needed.
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 the figure's significations ("Passion, anger, blood: ill omen") and a Group tag "Geomancy (Agrippa)", so an agent can infer this is a reference entry for the geomantic figure Rubeus. However, it never states the operation or payload explicitly (no verb + resource phrasing like "returns the Agrippa reference for the Rubeus figure"), and it does nothing to distinguish itself from the 15 sibling astroway_geomancy_* figure tools beyond the name. Purpose is inferable rather than stated.
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?
No guidance on when to call this versus the other geomancy figure endpoints, versus astroway_ai_interpret_element, or versus any divination tool. The only domain context is the Group tag, which implies usage inside a geomantic reading but is not an instruction.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.