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

Beyond the annotations, the description discloses important provenance and reliability behavior: the edition has a preface dated 1591, each column carries an archive page locator, unconfirmed text is withheld, the English meaning is AI-written and unverified by a human scholar, and results include attribution and a permalink. These are substantive behavioral details that an agent would not know from the readOnly/idempotent annotations alone.

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 front-loaded and appropriately sized for a retrieval tool, but it repeats the archive locator point in two separate sentences. The information earns its place overall, though minor redundancy keeps it from being maximally concise.

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 no output schema, the description still explains what is returned: trigrams, lines, judgement text, optional line text, archive locators, attribution line, and permalink. It also covers key caveats about provenance and unverified translation, making the tool sufficiently complete for an agent to call and interpret results.

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 schema already documents both parameters, including examples for hexagram and line. The description reinforces that retrieval is by hexagram number and that a line text is added if requested, but it adds no real syntax or semantic detail 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 a specific verb and resource: it returns one of the 64 Zhouyi/I Ching hexagrams by number, including trigrams, lines, judgement text, and optional line text. It is clear what the tool does, but it does not explicitly distinguish itself from sibling tools such as compute_heluo_birth_hexagram or other compute/retrieval tools.

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?

Usage is implied by phrases like 'by hexagram number' and 'one line text if asked', but there is no explicit guidance on when to choose this tool versus related siblings. The description does not state exclusions or alternatives, leaving tool selection mostly to inference from the tool name and resource description.

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