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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds only the list-all fallback behavior; it says nothing about return format (a list vs. a single definition) or size limits.

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 compact sentence with a parenthetical qualifier; the audience level and term list are front-loaded and the fallback behavior closes it out. Slightly dense but nothing is wasted.

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 two-parameter read-only lookup with no output schema, the description covers purpose, audience, and the zero-arg case. Only the return shape and language handling remain unstated, and the latter is in the schema.

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 50%: 'lang' is documented in the schema but 'term' carries no schema description and is only implicitly explained by the description's list-all behavior. The description never mentions language selection, leaving the enum to the schema alone.

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 resource (student-level definitions of orbital terms) and enumerates representative entries, so an agent can immediately tell this glossary lookup apart from the calculation tools in the sibling list (perigee_orbit, perigee_distance, etc.).

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?

Explicitly states the no-argument behavior: 'Without a term, lists them all,' which gives a clear call pattern. It does not name alternatives, but no sibling offers definitions, so that gap is minor.

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