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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false and destructiveHint=false, so the safety profile is covered. The description does add non-structured value by disclosing cost (10 credits, Tier 1), which matters for agent budgeting. It says nothing about output shape, but an output schema exists, so that gap is acceptable.

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?

One sentence of purpose plus compact bracketed metadata; nothing is padded or redundant. Structure is front-loaded with the operative verb and resource, and the cost/group tags scan cleanly.

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 described, and annotations cover the safety profile. However, for a tool with an unexplained required 'name' parameter and heavy sibling overlap, the description omits both parameter meaning and selection guidance, leaving real gaps for an agent deciding between 60+ numerology calls.

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 two required parameters (name, date) carry no schema descriptions at all, only pattern/length constraints. The phrase 'from the day-of-birth digit' loosely maps to date, but it never explains what 'name' should contain (full birth name? any name?) or why a Birthday calculation needs a name at all.

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 (Birthday number) and pins the system (Pythagorean), which is the main axis distinguishing it from the Chaldean/Kabbalistic/Vedic and numk/numks/numps siblings. It does not explicitly contrast itself with those alternatives, but the name+description pairing is unambiguous about what computation it performs.

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 guidance, no mention of prerequisites, and no routing to alternatives despite ~60 sibling numerology variants. The only scoping signal is the [Group: Numerology: Pythagorean] tag, which identifies family but not conditions for selection.

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