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

Annotations already declare readOnly/idempotent/non-destructive, so safety is covered; the description adds cost (10 credits, Tier 1), the endpoint, and the required fields, which are genuinely useful operational context. It stops short of noting anything about determinism of results or response shape.

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 front-loaded sentence stating the calculation, followed by a compact metadata block. Every line carries operational signal (group, endpoint, required, cost) with no filler.

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?

For a read-only calculation with an output schema present, the definition covers what the tool computes, its tradition, cost, and required inputs. Remaining gaps (date format nuance, compact-mode behavior) are handled by the schema.

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 60% (year, fields, precision documented; name and date bare), and the description only restates the two required parameters without adding format or meaning. This matches the baseline for partial schema coverage but adds no compensating detail.

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 ('Personal Year number for a given calendar year') and names the tradition ('Kabbalistic (phonetic) system'), which helps distinguish it from the Chaldean/Pythagorean/Vedic siblings. It does not, however, differentiate from the closely named kabbalistic_strict_personal_year or the alias target beyond the alias note.

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 description reveals this is a 'Cursor-friendly alias for astroway_numerology_kabbalistic_personal_year', which tells the agent when to prefer this spelling over the canonical tool, but it gives no guidance on choosing between numerology systems or the strict variant.

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