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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is established. The description adds behavioral value beyond annotations by disclosing that results include per-sector counts of public investors, a one-line description, example companies, and ordering by busiest sector first.

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 compact sentence that front-loads the core purpose and then packs the key output details (counts, descriptions, examples) and ordering into the remainder. No filler or repetition of annotation information.

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 parameterless read-only reference tool with no output schema, the description adequately covers what the response contains and how it is ordered. An agent can predict the tool's output and how to use it with the named sibling filters.

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 has zero parameters, and the input schema has no properties, so the description has no parameter semantics to clarify. The baseline of 4 applies because there is nothing for the description to add over 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 description clearly identifies the resource ('sectors an investor can list on their Signed profile') and specifies that it returns the valid sector filter values for list_investors and search_investors. It distinguishes the tool from sibling tools by framing it as the reference vocabulary behind their filters rather than an investor-list operation.

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 explicitly connects this tool to the sector filter on list_investors and search_investors, making the intended use clear: consult this before applying sector filters. It does not state when not to use it, but the relationship to the sibling tools is specific enough to guide selection.

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