Hexagram Lookup

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

Annotations already declare readOnlyHint, idempotentHint and non-destructive, so safety behavior is covered. The description adds a genuinely useful cost caveat ('endpoint not in the public credit manifest'), but says nothing about what data the response contains or caching behavior, and an output schema exists so returns need not be spelled out.

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, then bracketed metadata tags that are scannable and each carry distinct facts (group, endpoint, required param, cost). Slight redundancy: '[Required: number]' duplicates the required array and the title restates 'Hexagram Lookup'.

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?

With annotations, 100% param coverage and an output schema, much of the burden is already handled, and the cost note fills a real gap. What is still missing is the routing information — an agent cannot tell from the definition alone whether to look up a known hexagram or perform a casting.

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 100% and the single parameter already documents 'Hexagram number in King Wen order' with min/max 1-64. The description's '1-64 by King Wen number' merely restates the schema, adding no new semantics; baseline 3 applies.

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 ('Fetch hexagram 1-64 by King Wen number'), so an agent knows exactly what it returns. It does not differentiate from the four sibling I Ching tools (throw_coins, by_question, daily, with_changing_lines), which is the only clarity gap.

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?

No guidance on when to use this over astroway_iching_throw_coins or astroway_iching_by_question. The crucial distinction (this is a static reference lookup, not a cast) is left entirely for the agent to infer from the tool name.

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