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

Annotations already establish read-only, idempotent, non-destructive, closed-world behavior, so the bar is lower. The description still adds real operational context: the 20-credit cost, and the localization caveat that `meaningLocalized` may fall back to English with `translated: false` while a language's strings are pending.

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?

The return contents and the cost comparison are front-loaded, and the bracketed group/endpoint/required/cost block is scannable. It is slightly dense with metatext, but no sentence is wasteful for a tool with this many sibling variants.

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 explained, yet the description still previews `meaning`/`meaningLocalized`. Required inputs are surfaced via the bracket line. The only gap is that the referenced language selection has no corresponding parameter, leaving the localization trigger ambiguous.

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 60%, with `year`, `fields` and `precision` already documented in the schema, so baseline is 3. The description restates the `year` default (already in the schema) and mentions meanings come 'in the requested language', but no language parameter exists in the schema, so that hint is unactionable rather than additive.

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?

Names a specific verb+resource (returns the six core numbers in one call) and enumerates them: Life Path, Expression, Soul Urge, Personality, Birthday, Personal Year. It also states the system variant ('Kabbalistic (phonetic)') and the concrete alternative ('60 for six single calls'), which separates it from both the single-number siblings and the other chart schools.

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?

Explicitly frames the use case: get all six numbers together for 20 credits rather than issuing six single calls, which is a clear cost/coverage trade-off an agent can act on. It does not, however, tell the agent when to prefer a sibling such as astroway_numerology_kabbalistic_strict_chart or the Chaldean/Pythagorean/Vedic chart variants.

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