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

Even with no annotations, the description discloses key behavior: the list is dynamic ('change as data is added'), derived from the index's own annotations, and includes counts that indicate breadth (e.g., 'entity covers everything, a single lineage covers a handful'). It also clarifies that contains matching is case- and separator-insensitive, reinforcing the schema's explanation.

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?

Three sentences front-load the purpose, then provide contextual guidance and parameter examples. No wasted words; each sentence contributes meaningfully.

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 one-optional-param list tool, the description covers what it returns (type names with counts), the dynamic nature, and how to narrow results. While it doesn't specify an exact output schema, the description is sufficient for effective use, though it could mention whether results are sorted or paginated.

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 schema already covers the 'contains' parameter with a clear description and matching rule. The description adds concrete usage examples (e.g., contains='lineage' for ~120 lineage clones, contains='connectivity' for connectome facets) and explains how counts relate to the breadth of the name, enriching understanding beyond the schema.

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 opening sentence clearly states the function: 'List the type names search_terms can filter, exclude, boost or demote by, with the number of terms carrying each one.' This identifies both the action and the resource, distinguishing it from sibling tools like get_term_info or run_query.

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 advises 'Call this instead of guessing,' explaining that there are over 200 names, they are index annotations rather than a curated list, and they change as data is added. This sets clear expectations for when to invoke the tool—before using search_terms with filters—though it doesn't name alternative tools.

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