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

Annotations already mark this as readOnly/non-destructive, and the description adds meaningful behavioral context on top: the underlying three-coin method, seeded randomness, deterministic reproducibility (same seed + same date = same result), and what the output covers (line values, changing lines, transformed hexagram). No contradiction with annotations.

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, every one earns its place: what it does, how it differs, and when to use. It is front-loaded with the core behavior and contains no filler or redundant restating of the title.

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?

Given the simple option list, readOnly annotations, and no output schema, the description covers the essential output contents and behavior. It could be slightly more explicit about response fields, but the mention of line values, changing line positions, and resulting hexagram is sufficient for most orchestration decisions.

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 parameters are already fully documented in the schema. The description reinforces the seed/date relationship and the meaning of reproducibility but does not add significant parameter detail beyond the schema, which is acceptable at the baseline of 3.

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: 'Cast a complete daily I-Ching reading using the traditional three-coin method with seeded randomness.' It enumerates the distinguishing features (line values 6-9, changing line positions, resulting hexagram) and explicitly contrasts with 'the simple daily hexagram,' making it easy to tell apart from sibling tools like post_iching_daily.

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?

Gives clear usage context: this is for apps seeking an authentic oracle experience with daily consistency and reproducibility. It does not explicitly list alternatives by name, but the 'Unlike the simple daily hexagram' comparison implies when not to use it. This is solid guidance though it stops short of a fully explicit when-to-use/when-not-to-use matrix.

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