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 meaningful behavioral context: results are sorted newest first, source types are enumerated, and rows are the underlying facts for the funding_event signal. This goes beyond the structured annotations without contradicting them.

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, each earning its place: the first defines the core operation and return fields, the second explains provenance and retention value, and the third points to tools for finding the required ID. Information is front-loaded and there is 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 list tool with one required parameter, the description is largely complete: resource, ordering, fields, source types, provenance, and ID lookup are all covered. The main gap is the undefined limit parameter, but the tool's overall context is adequate for an agent to call it correctly.

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 coverage is 0%, so the description must compensate for missing parameter documentation. It implicitly explains companyId by saying 'a company's funding rounds,' but the optional limit parameter is not described at all. With no schema descriptions and no mention of what limit controls, parameter semantics are only partially covered.

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 states the verb ('List'), the resource ('a company's funding rounds'), the ordering ('newest first'), and the specific fields returned. It distinguishes itself from related siblings like list_company_signals and list_company_news_events by clarifying that these are raw funding facts that feed the funding_event signal.

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 gives clear context on when this tool is useful: after the derived funding_event signal expires, this history remains visible. It also provides direct guidance for finding company IDs via campaignstack_list_companies or campaignstack_get_company. It doesn't explicitly contrast with sibling list tools, but the context is clear enough for selection.

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