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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower. The description adds a genuinely useful behavioral fact the annotations do not carry: the cost of 10 credits (Tier 1), which lets an agent budget or warn the user before calling. It does not describe latency, caching, or error behavior, keeping it at 4.

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?

Extremely tight and front-loaded: the operative sentence comes first, then two bracketed metadata tags. No sentence is wasted, though the group/cost tags are boilerplate rather than tool-specific content.

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 no explanation, and annotations cover the safety profile. The description supplies the calculation basis and cost. The remaining gap is the undocumented required parameters (name/date semantics), which is minor for a straightforward single-value calculation tool.

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%: the optional 'fields' and 'precision' params are documented in-schema, but the required 'name' and 'date' have no descriptions. The phrase 'full birth name' adds some meaning to the name parameter (suggesting the complete legal/birth name rather than a nickname), but the date parameter is left entirely to the schema pattern. This only partially compensates for the coverage gap, so baseline 3.

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+resource ('Calculate the Personality number') and the actual computational basis ('from the consonants of the full birth name'), which meaningfully distinguishes it from sibling soul_urge (vowels) and expression (all letters) tools. It also names the Chaldean system, separating it from the Pythagorean/Kabbalistic/Vedic personality variants. It stops short of explicitly naming those siblings, so it is clear but not maximally differentiated.

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 or when-not-to-use guidance. An agent gets no help choosing between this, astroway_numerology_kabbalistic_personality, astroway_numerology_pythagorean_personality, and the other Chaldean sub-numbers (life_path, soul_urge, etc.). The [Group] tag is a taxonomy label, not usage instruction.

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