9-Rune Cast

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and closed-world behavior, so the safety profile is covered. The description adds genuinely new operational information in the cost line (10 credits, Tier 1) and the endpoint, which matters for a metered API. It does not disclose whether results vary with the seed or what the spread positions mean, so it stops short of rich behavioral context.

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?

Extremely compact and front-loaded, with the identifying phrase first and metadata bracketed after it. Nothing is padded, though the single identifying sentence is arguably too thin rather than too long.

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. But with three fully undocumented parameters, no usage guidance against close rune siblings, and no explanation of the Pennick spread itself, the definition is not sufficient for an agent to invoke it confidently.

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 0% for three parameters, so the description must carry the burden and does not. In particular, `seed` (number or string) is completely unexplained — an agent cannot tell whether it makes the cast deterministic or is optional entropy, and `allowReversed` and the 400-character `question` limit are likewise unaddressed.

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?

"Pennick layout 9-rune cast" names a verb (cast) and a specific 9-rune spread, and the name distinguishes it by count from siblings like astroway_runes_single and astroway_runes_three. However, "Pennick layout" is jargon with no explanation, and the description never says what a nine-rune cast is for or produces, so an agent relying on the description alone has only a partial picture.

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 statement of when to choose the 9-rune cast over the three-rune or single-rune tools, no prerequisites, no exclusions. The only routing signal is the number in the tool name, which the agent must infer.

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