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

The annotations already mark the tool as read-only and idempotent, and the description adds genuinely useful behavioral detail: what 'match' can return and that 'none' is a successful miss rather than an error. This goes beyond annotation-provided information without contradicting it.

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, front-loaded with the core purpose, and every sentence earns its place. It communicates purpose and the key behavioral outcome in just two sentences with no filler.

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 read-only lookup tool with a rich output schema and safety annotations, the description covers the main outcome modes and the 'successful miss' nuance. It does not discuss sibling selection or provide examples, but the schema and annotations fill most remaining gaps.

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%, so the schema already documents both parameters. The description adds slight context with 'admitted glossary term' for the term parameter, but it contributes nothing specific to expected_revision semantics beyond what the schema provides.

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 uses a specific verb, 'Define', and identifies the resource as 'one admitted glossary term,' with concrete outcome states for the match field. It is clear what the tool does, though it does not explicitly differentiate it from sibling tools like atlas_read.

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 guidance on when to use this tool versus its siblings, and no alternatives are named. The phrase 'admitted glossary term' implies a restricted scope, but the description gives no when-to-or-when-not-to guidance.

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