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

Annotations already provide readOnly and idempotent hints. The description adds valuable context that this is a compact/summary index and includes license/attribution requirements (data © IChing.Rocks), which is beyond what annotations convey. No behavioral surprises are hidden.

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?

Three sentences, all information-dense: what the tool returns, optional parameter, and when not to use it. No filler or repetition; front-loaded with the core function.

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?

The tool is simple (one optional param, output schema provided) and the description fully covers its purpose, variants, and relationship to sibling tools. License mention also covers important usage context.

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?

The schema already documents the single 'order' parameter with enum values and default. The description reinforces this by listing the allowed order values and explicitly stating kingwen is the default, adding clarity beyond the schema.

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 states the tool lists a compact index of all 64 I Ching hexagrams with specific fields (id, name, pinyin, characters, essence, trigrams, url). It clearly distinguishes from get_hexagram/get_hexagrams (returns full detail) and get_all_hexagrams (returns full dataset) by calling itself the 'summary index only.'

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 explains when to use this tool vs. alternatives: use it for the summary index, get_hexagram(s) for full detail on a known number, get_all_hexagrams for the full dataset, and search_hexagrams for text search. Also notes optional order with a default.

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