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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds important behavioral context: data is 'read as published and never computed' and it explicitly mentions that anything not published for the build is stated. This transparency about data provenance and limitations is valuable beyond the annotations.

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 a single, dense sentence (with a follow-up sentence) that front-loads the core question and then enumerates what is covered. It is efficient but could be slightly more structured with bullet points or clearer separation of categories for readability.

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?

Given the tool's simplicity (no parameters, no output schema), the description provides a complete picture of what the summary includes and the constraint that only published data is used. It adequately prepares the agent to interpret the output, though it might benefit from mentioning the format (e.g., structured text or JSON) since there is no output 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?

The tool takes zero parameters, so parameter semantics are not applicable. The description does not need to explain any parameters, and the baseline for zero parameters is 4, which is appropriate here.

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 states a specific purpose: summarizing what CourseShelf holds, with concrete details about catalog areas, institutions, row counts, sectors, and verdicts. It distinguishes itself from sibling tools like get_institution or find_programs by focusing on aggregate holdings. However, the initial rhetorical question ('What does CourseShelf hold?') is slightly less direct than a clear verb-resource statement.

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 implies usage by asking about holdings and enumerating what it provides, but it does not explicitly state when to use this tool versus alternatives like get_institution or list_issuers. No exclusions or alternatives are mentioned, leaving the agent to infer that this is for aggregate summaries rather than detailed queries.

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