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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and a closed world, so the safety profile is covered. The description adds genuinely new behavioral context: the reduction method (year+month+day, reduced) and the cost (10 credits, Tier 1), which an agent needs for budget decisions. It still omits any error/edge-case behavior.

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?

Two short sentences plus compact bracketed metadata; the purpose is front-loaded and nothing is wasted. The group/cost tags are boilerplate but carry real routing and budget 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?

With an output schema present, return values need not be described, and annotations cover safety, so the core is adequate. The unresolved required 'name' parameter and the lack of any when-to-use guidance leave gaps for a tool competing against dozens of near-identical 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?

Schema coverage is 50%: fields and precision are documented in the schema, while date and name are not. The description clarifies that date is a birth date reduced from year/month/day, but the required 'name' parameter is left entirely unexplained and sits awkwardly against the 'from birth date' framing, adding no compensating meaning.

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?

States a specific verb (Calculate) and resource (Life Path number) and identifies the system ('Chaldean system'), which is the key axis separating it from the Kabbalistic/Pythagorean/Vedic life_path siblings. It stops short of explicitly contrasting with those siblings, but the resource+system combination is enough for an agent to place it.

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?

Usage is only implied through the 'Numerology: Chaldean' group tag; there is no statement of when to choose this over the many sibling life_path tools or any prerequisites/exclusions. An agent can infer it, but the description does no active routing.

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