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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds value beyond that by enumerating the returned columns (amount offered/sold, first sale date, security types, investor count, crowdfunding platform, filing link) and by disclosing a data-coverage limitation about what EDGAR does not contain. It doesn't mention latency, empty-result behavior, or per-row charging semantics beyond the schema.

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?

Two sentences, front-loaded with the action and resource, then the return contract. The long parenthetical field list is dense but each item is informative rather than filler. Minor cost: the field enumeration makes the second sentence heavy to scan.

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?

With six optional parameters and no output schema, the description compensates by specifying the two-tier row structure and the notable fields returned, plus the EDGAR coverage boundary. An agent can decide whether this tool answers a question and predict its output shape without additional documentation.

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 description coverage is 100%, with enums on forms and match fully documented inline, so the schema carries the parameter burden. The description only echoes the Form D/Form C distinction implicitly through its return-shape discussion and adds no new syntax or constraint detail for companies, filed_after, max_charge_usd, or max_rounds_per_company. Baseline 3 is appropriate.

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?

States a specific verb and resource ('Look up private US companies on SEC EDGAR by legal name or CIK') and then describes the exact return shape: one company row plus one row per Form D or Form C offering. An agent knows precisely what the tool does and what comes back without opening anything else.

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?

Gives a clear applicability boundary: 'Primary SEC filings only; rounds raised outside Regulation D and Regulation CF are not on EDGAR,' which tells the agent when results will be empty or incomplete (e.g., non-US companies, VC rounds not filed on Form D). There are no sibling tools to route against, but it stops short of an explicit when-to-use statement such as 'use for private-company fundraising research.'

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