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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds a genuinely useful fact not in structured data: the 10-credit Tier 1 cost. It says nothing else about behavior, but with annotations carrying the main burden a 3 is fair.

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: the purpose line comes first, then group/cost metadata, then the alias note. Every line is compact, though the alias sentence is only marginally valuable to a selection decision.

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 15-parameter tool with only 33% schema description coverage, a vague one-line purpose leaves too much unexplained. Output schema existence relieves the need to describe return values, but the input side and the tool's distinct role among many near-identical siblings are not covered.

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 33% across 15 parameters, and the description contributes zero parameter meaning — no mention of required date/time/lat/lon, the enum choices, compact-mode fields, or timezone handling. With a low coverage rate, the description should compensate and does not.

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 says it returns a 'single-keynote signature for the chart', which partially restates the title 'Rudhyar: Personality Keynote' without explaining what a keynote signature actually is or what it contains. It does at least identify the resource as a chart signature and flags the group, but it distinguishes nothing from siblings such as symbolic_degrees or lunation_phase.

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 when-to-use guidance, no prerequisites, and no alternatives named. The only contextual information is the credit cost and the group label, which do not tell an agent when this tool is preferable to the ~40 sibling psychological tools.

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