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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds genuine behavioral value by disclosing the cost (10 credits, Tier 1), which is not in any structured field, but it says nothing about computation, auth, or what happens with missing inputs.

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?

It is short and the group/cost tags are front-loaded, but the body is an under-specified fragment rather than a complete statement, so brevity comes at the cost of information rather than from efficient editing.

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, but for a 15-parameter chart-calculation tool requiring date, time, and coordinates, the description omits input requirements, timezone handling, and any usage context. An agent has almost nothing to act on beyond the cost tag.

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%, so the description is expected to compensate, and it does not mention a single parameter. The four required inputs (date, time, latitude, longitude) carry no descriptions anywhere, and complex fields like timezone vs timezoneOffset are left entirely to the schema.

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 is a noun fragment listing output categories ("Personality + temperament + best-suited household") rather than a verb+resource statement of what the tool computes. It never says it derives meaning from the pet's Sun sign, and it fails to distinguish itself from siblings astroway_pet_personality and astroway_pet_temperament, whose names overlap directly with the stated outputs.

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 prerequisites, and no mention of alternatives, despite many near-identical pet siblings. The [Group: Pet Astrology] tag gives domain placement only, which is not usage direction.

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