Does 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 new operational context the annotations do not carry: the HTTP endpoint, the 10-credit Tier 1 charge, and the required input set — useful for budgeting and call planning.

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?

Compact and front-loaded: the purpose leads, bracketed metadata follows, and the alias note is placed last. No filler sentences, though the bracket block is terse enough that some lines (endpoint) carry little decision value.

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, credit-charged endpoint with low schema coverage, the description leaves major gaps: no indication of which optional parameters matter, no defaults guidance, and no differentiation from the psychological sibling family. The existing output schema and annotations cover return shape and safety, but the input-side context is thin.

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 only 33% across 15 parameters, so the description is expected to compensate, and it does not. It merely restates the four required parameters already marked required in the schema and says nothing about ayanamsa, timezone/timezoneOffset, houseSystem, fields, or precision semantics.

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?

"Single-keynote signature for the chart" names a resource and a method (Rudhyar, via title/alias) but never explains what a 'keynote signature' actually is or what it returns conceptually. It is distinguishable from other Rudhyar tools only weakly, through the 'keynote' word; the alias sentence adds identification value but not purpose.

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 this tool over the many sibling psychological/interpretation tools (e.g. astroway_psyr_symbolic_degrees, astroway_ai_interpret_element). Only required inputs and cost are given, which is operational metadata, not usage guidance.

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