By Question

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

Annotations already declare readOnly/idempotent/non-destructive, so safety is covered. The description adds genuinely new context, the 10-credit Tier 1 cost and the group/endpoint, but says nothing about whether any state persists or how the deterministic mapping is seeded.

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 core behavior leads in a single clause, and the bracketed metadata block is compact and scannable. Slight redundancy in restating '[Required: question]' which the schema already enforces.

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?

An output schema exists, so return values need not be described. For a single-param read-only divination endpoint, the definition supplies purpose, cost, endpoint, and the deterministic trait, which is enough for an agent to call it correctly.

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?

One parameter with 0% schema description coverage, so the description must compensate. 'Question text' does signal free-form natural language input, but it omits the 2-500 character bounds and repeats '[Required: question]' from the schema rather than enriching it.

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+resource: derives a hexagram from question text, and 'deterministic' distinguishes it in spirit from astroway_iching_throw_coins. It never names a sibling outright, so the differentiation is implied rather than explicit.

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 statement of when to use this versus astroway_iching_throw_coins, astroway_iching_lookup_number, or astroway_iching_with_changing_lines. The word 'deterministic' is the only hint that this is the non-random variant, which the agent must infer.

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