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

Annotations declare readOnlyHint=false, idempotentHint=true, destructiveHint=false, so the safety profile is already structured. The description adds nothing about whether 'mutate_line' actually changes persistent state or merely computes a derived hexagram — a meaningful distinction for an I Ching tool — so it leaves a real behavioral ambiguity unaddressed.

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 stating purpose, followed by a compact enumeration of return fields. The field list is dense but earns its place given there is no output schema. No filler or repetition.

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 usefully enumerates the return payload (King Wen number, binary symbol, trigrams, Wu Xing element, codon, nuclear, complement, reverse, dynamic transformations). Parameters are fully covered by the schema. The remaining gap is the semantics of 'mutate' — computed vs. persisted — which keeps it from a 5.

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 accepted query forms (name, pinyin, number, Unicode symbol) and the 1-6 line range for mutate_line. The description adds no syntax or format detail beyond that, so the baseline of 3 is appropriate.

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 gives a specific verb ('Inspect or mutate') and a specific resource ('one of the 64 King Wen I Ching Hexagram Macro-Actions'), so the agent knows exactly what object is being operated on. It does not explicitly differentiate from siblings like sutra.list or sutra.cast, so it falls short of a 5.

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?

There is no explicit guidance on when to use this tool versus sutra.list (presumably to enumerate all 64), sutra.cast (presumably to generate a reading), or sutra.canon. The word 'Inspect or mutate' hints at two modes, but the agent has to infer when each applies.

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