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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds the deterministic digit-sum reduction method, which is useful, but says nothing about the credit cost, output shape, or what happens for an invalid date.

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 tight sentences, front-loaded with the core purpose, plus a compact group/cost footer. It would be a 5 if the phantom date parameter were removed rather than being the sole usage sentence.

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 needn't be described, and annotations cover safety, so the remaining burden is light. Still, the description neither differentiates from siblings nor reconciles its date-query claim with the schema, leaving a gap for a low-complexity but crowded tool family.

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 100% for the two real parameters (fields, precision), so the schema does the heavy lifting. The description instead advertises an optional `?date=YYYY-MM-DD` query parameter that does not exist anywhere in the input schema, which actively misleads rather than adds 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 and resource ('Compute today's personal angel number from date') plus the algorithm (digit-sum reduced to single digit), which is more informative than the title alone. However, it never distinguishes itself from siblings like astroway_esoteric_angel_numbers, _number, _decode, or _by_life_path_n, leaving the agent to infer that 'today' is the differentiator.

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?

The only usage hint is 'Optional ?date=YYYY-MM-DD query', with no statement of when to pick this tool over the other four angel-number siblings. There is also no note that omitting the date defaults to today, which is the whole point of the tool.

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