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

Annotations already cover safety (readOnly, idempotent, non-destructive), and the description adds substantial context on top: the full status vocabulary (confirmed/not_found/partial/out_of_scope/out_of_coverage), the itemised claimed-vs-filed behavior for partial matches, and the explicit 'Rule-2: no estimates — absence is reported as absence' policy. That is meaningful disclosure beyond the structured fields.

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?

Front-loads the purpose, then enumerates return statuses compactly, ending with the no-estimates rule. Dense but each clause carries information; the status list is long but necessary given no output schema exists.

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 no output schema, the description compensates by enumerating every possible status and noting that the coverage window is always reported. For a 9-parameter verification tool this gives the agent everything needed to interpret results and call it 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 description coverage is 100%, so the schema already documents every parameter, including the ±3 filing-day and ±0.5pp tolerances. The description only restates the claim dimensions (ticker/subject, filer, percent, intent, timeframe) without adding matching semantics beyond what the schema provides, so the baseline 3 applies.

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?

Starts with a specific verb+resource ('Check a claim about an activist stake ... against the filed Schedule 13D/13D-A record') and enumerates the claim dimensions it evaluates. It is clearly distinguishable from the sibling verifiers (verify_13f_holding, verify_8k_event, verify_insider_purchase) by naming the 13D/13D-A filing domain.

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 explicit scope boundaries: passive 13G returns out_of_scope and claims outside the collected window return out_of_coverage, with the coverage window always reported. It lacks explicit routing to sibling tools for out-of-scope cases, so it stops just short of full when/when-not/alternatives guidance.

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