Core Numbers Chart (chaldean)

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

Annotations already cover safety (readOnly, idempotent, non-destructive, closed-world), so the description's real contribution is cost (20 credits, Tier 2) and the localization fallback contract — 'translated: false with the English text while a language's strings are on their way' — which no structured field conveys. That fallback behavior is exactly the kind of non-obvious trait an agent needs; the only gap is that it doesn't say whether results are cached or deterministic across repeated calls.

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?

Front-loaded with the payload (six numbers in one call), then cost, then localization caveat — each sentence adds distinct information with no restatement of the title or annotations. Appropriately sized for a three-parameter batch calculation.

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 the description doesn't need to enumerate return shape, and it wisely limits itself to the `meaning`/`meaningLocalized` contract. With annotations covering safety and cost covered inline, the only real shortfall is the unresolved ambiguity of what `name` and `date` should contain.

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 only 33%, so the description should carry more weight than it does. It matches the schema on `year` (defaults to current year) but adds nothing about `date` (birth date? which calendar?) or `name` (full birth-certificate name needed for Expression/Soul Urge/Personality, length limits), both of which materially affect results for a Chaldean name-based calculation.

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 resource and scope: 'The six core numbers in one call' with all six named (Life Path, Expression, Soul Urge, Personality, Birthday, Personal Year) and pinned to the Chaldean system. The bundle framing plus credit comparison makes it distinguishable from the single-number siblings (astroway_numerology_chaldean_life_path, _expression, etc.) without opening any schema.

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?

'20 credits instead of 60 for six single calls' effectively communicates the selection criterion: use this when you need multiple core numbers rather than one. What's absent is an explicit statement of when to prefer an individual tool (e.g. when only one number is needed) — the agent must infer that reverse case from the cost arithmetic.

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