lookup_cik

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It discloses the data source (SEC's company_tickers.json), coverage (10,000+ US tickers), cache freshness (24-hour window), and the metadata returned (entity name, SIC code, tickers, exchanges, fiscal year end, addresses). This is strong context, though it doesn't explicitly state the operation is read-only.

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 six sentences, front-loaded with the core purpose. Each sentence adds value—explaining the CIK, the workflow, metadata, data source, and caching—though it could be slightly tightened without losing meaning.

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?

Despite having no annotations and only one parameter, the description covers the tool's purpose, role in the pipeline, data source, freshness, and returned metadata. With an output schema present, it doesn't need to describe return values. Minor gaps like error handling or invalid ticker behavior are acceptable for this simple lookup 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?

Schema coverage is 100% with a clear description for the 'ticker' parameter ('Stock or ETF ticker symbol'). The description adds context about US ticker coverage but does not meaningfully enrich the parameter beyond what the schema already provides, so the baseline score of 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?

The description clearly states the tool's function with a specific verb and resource: 'Look up a ticker's SEC Central Index Key (CIK) and entity metadata.' It distinguishes itself from sibling resolvers by focusing on SEC CIK and explicitly positions itself as a prerequisite step for get_etf_holdings.

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 says 'This is the first step before calling get_etf_holdings,' providing clear when-to-use context. However, it does not mention when not to use the tool or compare it directly with sibling tools like resolve_ticker, resolve_cusip, or resolve_figi.

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