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

Annotations already declare readOnly/idempotent/non-destructive/non-open-world, so the safety profile is covered. The description adds genuinely new operational context: the credit cost ('10 credits (Tier 1)'), the endpoint, and the required-parameter set. It also notes the reduction method, though it doesn't detail error behavior or numeric validation.

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?

Front-loaded with the core purpose in the first sentence, with machine-readable metadata tags kept short. Every element is compact and carries information; the bracket tags are slightly noisy but not wasteful.

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 the description supplies purpose, required inputs, cost, and endpoint for a simple calculation tool. The one meaningful gap is cross-system selection guidance, which the sibling set arguably makes necessary.

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 50% (only 'fields' and 'precision' are documented in-schema). The description partly compensates by clarifying that 'date' is a birth date and that name/date are required, but it adds nothing about the name format or the compact-mode 'fields'/'precision' interaction beyond what the schema already says.

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'), a specific resource ('Life Path number'), and the disambiguating system ('Pythagorean'). This cleanly separates it from sibling life-path tools in the Chaldean, Kabbalistic, Vedic, numks and nump families without needing to open any schema.

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 guidance on when to choose the Pythagorean life path over the Chaldean, Vedic, or Kabbalistic life-path siblings, nor any prerequisites or exclusions. The '[Group: Numerology: Pythagorean]' tag is context metadata rather than usage direction, so an agent gets no routing help.

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