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

With no annotations provided, the description carries the full burden, and it does disclose the shape of the return value: grid occupancy, planes, arithmetic trail, and a short reading. It omits any statement of read-only/pure-computation semantics or performance characteristics, but the deterministic birth-date-to-grid framing makes the non-mutating nature effectively implied.

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?

A single front-loaded sentence covering input and output, followed by a compact example. Every clause earns its place and nothing is padding.

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?

There is no output schema, so the description must describe return values, and it lists the grid contents, planes, arithmetic trail, and reading clearly enough for an agent to know what comes back. It stops short of describing the exact response structure or field names, which would be the remaining gap.

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 100% and the single parameter is fully documented in the schema, including the pattern and the 1900–2100 range, so the baseline is 3. The description adds a concrete example input ({"dob":"1990-05-14"}) and repeats the YYYY-MM-DD format, which is genuinely useful for correct invocation.

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 gives a specific verb+resource: it takes a birth date and returns a filled 3x3 Lo Shu grid with present, missing and repeated numbers. This is clearly distinct from numerology siblings (lifePath, nameNumber, compatibility) that compute other things, though the description does not explicitly name those alternatives.

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 implied by the single-input design and the description of the output, so an agent can infer when to reach for this tool. However, there is no explicit statement about when to use this over the sibling numerology tools, and no prerequisites or exclusions are given.

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