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

With no annotations, the description carries full burden. It transparently discloses the key behavioral nuance: rows without the plan flag are unknown, and the tool reports how many such rows exist. It also enumerates what the response will contain (record type rows, distinct filers, date spans, share flagged), going beyond a simple 'list' statement. It stops short of discussing pagination, ordering, or data freshness, but for a coverage-introspection tool this is sufficient.

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 three sentences, front-loaded with the answer to 'what does this do', followed by when-to-use and how to scope. Every sentence earns its place with no filler or redundancy.

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 single-optional-parameter coverage tool with no output schema, the description fully covers the return content, the meaning of the plan flag limitation, and how to narrow the query. It is complete enough for an agent to decide when to invoke it and what to expect, without needing to infer details from sibling tools.

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 schema provides only a bare 'ticker' string with zero description. The tool description compensates by explaining that passing a ticker gives per-company coverage, which implicitly defines the no-ticker case as aggregate coverage. This adds meaningful context beyond the raw schema and is adequate for a single optional parameter.

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 what the tool does: reports insider history coverage by date, record type, filer counts, date spans, and the proportion of rows with a Rule 10b5-1 plan flag. It distinguishes itself from the related insider tools by explicitly telling the agent to call it before treating a plan split as complete, making its purpose and scope unmistakable.

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 explicit when-to-use guidance: call this before reading a plan split as complete, because rows without the flag are unknown and this tool quantifies them. It also explains the optional ticker parameter. It lacks explicit alternatives or when-not-to-use scenarios, but the trigger condition is clear and actionable.

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