Healing Crystals by Sign

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds two genuinely non-structured facts: the transport (POST /v1/wellness/crystals) and the price (10 credits, Tier 1), which is real value for an agent managing a budget. It does not say whether the birth data is used to derive the sun sign or the full chart, which is the key behavioral unknown.

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?

Nothing is padded: one content line plus four compact bracket-tagged metadata lines, front-loaded with what the tool returns. The trade-off is that the terseness is achieved by omitting a verb and all usage context, so it is efficient but under-informative rather than tight.

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 13-parameter tool that takes full birth data (date, time, lat, long) just to produce a sign-based crystal list, the description never explains why that much input is needed or how the sign is derived. The one thing it need not explain — return values — is covered by the output schema, but the sibling ambiguity and parameter gaps leave the definition materially incomplete.

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 23% across 13 parameters, so the description must compensate and it does not. '[Required: date, time, latitude, longitude]' merely restates the schema's required array, and the nine optional astrological knobs (ayanamsa, houseSystem, zodiacType, timezone, timezoneOffset, cosmogram) go entirely undiscussed — including whether they change the crystal output 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?

The fragment 'Primary + supportive crystals + intentions per zodiac sign' tells the agent what content comes back, but it is a noun phrase with no verb and no stated input (birth data). Critically, it does not distinguish this from the near-identical sibling astroway_esoteric_crystals_by_zodiac_sign, so an agent cannot confidently pick between them.

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 statement, no exclusion, and no mention of alternatives. The sibling list contains five other crystal tools (esoteric_crystals, _by_chakra, _by_purpose, _by_zodiac_sign, _recommend) and the description gives no rule for choosing this one over them.

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