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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description adds meaningful behavior beyond that: it discloses that results are 'summary data' rather than full healing properties and identifies the detail endpoint for more complete information. This helps the agent set the right expectations without over-claiming.

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 description is three sentences long, with the core purpose and element scope front-loaded. The sentence about essential use cases adds some contextual value but is slightly promotional and not strictly necessary. Still, no sentence wastes the reader's time and structurally it is clean.

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 list tool with annotations covering safety and a fully described parameter schema, this description is adequate: it clarifies the returned scope (summary data), points to the detail endpoint for more depth, and notes the valid elements. The lack of an output schema is mitigated by the 'summary data' statement, though exact return shape is not specified.

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%, and the description adds little beyond what the schema already documents for element, lang, limit, offset, and compact. The only parametrically relevant addition is enumerating the five elements, but the schema already does that via an enum. A baseline of 3 is appropriate.

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 description names a specific verb-object pair ('Get healing crystals and gemstones associated with a specific natural element') and distinguishes the tool from its siblings by focusing on element filtering. It also enumerates the five supported elements, making the resource scope unambiguous.

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 provides clear application context via 'elemental crystal selection, nature-based healing, and element-themed crystal grid applications' and explicitly directs users to the /crystals/{id} detail endpoint for fuller properties. It does not explicitly list exclusions or what to use instead for other filter dimensions, but the element-specific scope is unmistakable.

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