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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds useful non-annotation context: the HTTP endpoint path and a cost caveat that the endpoint is not in the public credit manifest, which is worth knowing before calling. It says nothing about result size, pagination, or unknown-chakra behavior.

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 with the essential resource and its value domain, followed by a compact metadata block. No filler, though the bracketed metadata lines add bulk that could be tighter.

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 no explanation, and all three parameters are documented. The only meaningful gap is sibling disambiguation among the four other crystal tools, which an agent choosing between them would want.

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 100%, so the baseline is 3, but the description goes further by enumerating the accepted chakra names (Root through Crown), which the schema does not provide as an enum. It still leaves case/format expectations to the schema's 'lowercase' note.

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-and-resource pairing ('Crystals indexed for a given chakra') and enumerates the seven valid chakra values, so the agent knows exactly what it returns. It does not explicitly contrast itself with the sibling crystal endpoints (by_purpose, by_zodiac_sign, crystals_recommend), so it stops short of a 5.

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 and no mention of when to prefer this over astroway_esoteric_crystals_by_zodiac_sign or astroway_esoteric_crystals_by_purpose_purpose. Usage is only implied by the 'given a chakra' phrasing and the enumerated values.

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