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

With no annotations, the description carries the burden of disclosing behavior. It usefully reveals this is a deterministic local lookup, not generative AI. However, it doesn't describe the output format, whether verses are in Chinese or translated, or what happens for invalid hexagram combinations, so transparency is partial.

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 compact—two sentences—with the core action front-loaded. Every phrase earns its place, and there is no redundant information.

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?

For a simple lookup tool with two integer parameters and no output schema, the description adequately covers the purpose and nature of the tool (local source vs AI). It could mention return format or error handling, but these are not critical for a minimal understanding.

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 input schema already fully describes both parameters with ranges and meaning (1-64). The description adds the relationship between primary and changing hexagrams, but this is marginal since the schema covers each parameter's semantics. Baseline of 3 applies due to 100% schema coverage.

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 clearly states the tool's function: look up a 焦氏易林 verse for a primary hexagram changing into another. It uses a specific verb ('look up') and resource, and distinguishes itself from sibling tools by clarifying it's a local classical-source lookup, not an AI reading.

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?

The description provides context on when to use this tool by noting it's a local classical-source lookup rather than an AI reading, implying it's for retrieving exact verse text. However, it doesn't explicitly name alternatives or state conditions like 'use this when you need a literal verse rather than interpretation.'

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