US Government Open Data MCP

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It describes the return fields (company name, tickers, etc.) and implies a read-only operation by stating 'Look up' and 'Returns', but does not explicitly state whether it's read-only, requires authentication, has rate limits, or other behavioral traits. The description adds some context (e.g., recent filings list) but lacks comprehensive behavioral details, resulting in a baseline score.

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 well-structured and front-loaded with the core purpose in the first sentence. Additional sentences provide useful examples and guidance without redundancy. Every sentence earns its place by adding practical value (e.g., CIK examples, alternative tool reference), making it efficient and easy to parse.

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 low complexity (1 parameter, no output schema, no annotations), the description is largely complete. It covers the purpose, usage guidelines, parameter examples, and return fields. However, it lacks details on error handling, rate limits, or authentication requirements, which could be relevant for a data lookup tool. The absence of an output schema means the description must fully explain returns, which it does adequately but not exhaustively.

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 input schema has 100% description coverage for the single parameter (cik), so the baseline is 3. The description adds value by providing examples of CIK numbers for specific companies (e.g., Apple: 0000320193) and clarifies that leading zeros are optional, which enhances understanding beyond the schema's description. However, it does not explain edge cases or validation rules in depth, keeping it from a perfect score.

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 tool's purpose with specific verbs ('Look up') and resource ('company on SEC EDGAR by CIK number'), and distinguishes it from sibling tools by mentioning sec_filing_search as an alternative for finding CIK numbers. It explicitly lists the return fields (company name, tickers, SIC code, state, recent filings list), making the purpose highly specific and differentiated.

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 provides explicit guidance on when to use this tool ('Look up a company on SEC EDGAR by CIK number') and when to use an alternative ('To find CIK: search by company name using sec_filing_search'). It includes practical examples of CIK numbers for common companies, which helps users understand the input format and when this tool is appropriate versus the sibling tool.

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