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

Annotations already establish readOnly, idempotent, and non-destructive behavior. The description adds useful behavioral specifics, including attribution level, source quote, and the explicit clarification that amount means the round amount, never the check. This prevents a common misinterpretation of the returned data.

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 dense but efficient: it front-loads the output fields and closes with the filter options. Every clause carries useful information, though splitting output and filtering into separate sentences would improve 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 that no output schema exists, the description enumerates the key return fields and the main query dimensions. It leaves minor ambiguities such as whose state is being filtered, but it is adequate for a read-only search tool.

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?

With only 56% schema coverage, the description compensates by naming the otherwise undocumented filters: stage, since-date, and lead-only. It does not define accepted values or date formats, but for most parameters it adds meaning beyond the bare 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 defines the resource as investor-by-investor round participations and enumerates the specific output fields that distinguish it from sibling tools like search_vc_firms or search_vc_funds. The granularity and scope are unambiguous.

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 lists filter dimensions such as investor, company, partner, stage, state, since-date, and lead only, but it never explains when to prefer this tool over alternatives like search_vc_funds or search_family_office_investments. No when-to-use, when-not-to-use, or comparison guidance is provided.

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