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

Annotations already set readOnlyHint=true, idempotentHint=true, and destructiveHint=falselint. The description adds substantial behavioral context: aggregation across all filings, ever_* relationship filter semantics, owner_name coming from the most recent filing, caveats for name_changed, plan history window coverage, 403 error behavior with charge, and the 30-credit cost. No contradictions with annotations.

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 dense but every sentence adds value: core purpose, resolution use, relationship filter semantics, return field meanings, plan limits, error behavior, cost, and endpoint. Information is front-loaded with the most important purpose and usage guidance first, then details in natural order.

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?

Even without an output schema, the description thoroughly explains return fields (filing_count, form4_filing_count, form3_filing_count, owner_name, name_changed, latest_officer_title, officer_title_as_of), filtering semantics, plan constraints, and error handling. This is complete for an agent to understand what it will receive and how to use the tool 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 100%, so the baseline is 3. The description adds meaningful value by explaining that the relationship filter takes ever_* values and means 'ever reported in this role,' and contrasts it with the per-filing is_* form found in other tools. This goes beyond the schema's enum list and helps clarify parameter semantics.

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 states a specific verb and resource: it lists all insiders of one company, one row per SEC CIK, aggregated over Form 4 and Form 3 filings. It clearly defines the output granularity and distinguishes it from related tools like list_insider_transactions by emphasizing the aggregation and CIK-level granularity.

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 states when to use this tool: to resolve a person to the insider_cik used by list_insider_transactions, get_insider_stats, and list_initial_holdings. It also names alternatives for per-filing is_* semantics (get_insider_stats, search_insider_trades), providing clear routing guidance.

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