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

Annotations already declare readOnly, idempotent, closed-world and non-destructive, so safety needs no restating. The description adds real value beyond them by disclosing the return payload — title plus summary, full text for the richer element kinds, and linked centres/channels/gates — which matters because there is no output schema. It does not say what happens for an unrecognized or ambiguous term.

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 purpose and the accepted input vocabulary are front-loaded in the first sentence, and the second sentence is devoted entirely to what comes back. Dense but every clause carries information an agent needs.

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 two-parameter read tool with full schema coverage and no output schema, the description covers purpose, input vocabulary and return shape adequately. The one gap is error/ambiguity behavior for unknown or loosely matched terms, which an agent would have to discover by calling.

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 coverage is 100%, so the schema already documents both parameters and the language enum. The description still adds semantic structure beyond the examples by grouping the accepted inputs into named element categories and tying category to response depth (full text for types, authorities, profiles, definitions and basics).

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 ("Explains") and a single, well-bounded resource ("one Human Design element") and then enumerates the element kinds it accepts, each with an example. That enumeration lets an agent distinguish this glossary lookup from the chart-computing siblings without opening any schema.

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 enumerated categories plus examples make the intended context clear: this is a definitional lookup for a single term. It does not, however, name an alternative or state when to choose compare_charts/get_chart/get_transits instead, so routing between siblings is left partly to inference.

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