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

Annotations already establish idempotence and read-only safety. The description adds useful behavioral context beyond that: it is sourced from the SEC IAPD public API, requires no API key, and returns all Form ADV Part 1 fields. It does not discuss rate limits or error behavior, but the disclosures made are meaningful.

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: a direct first sentence stating what the tool does, a concise list of use cases, and a short source/auth note. Every sentence earns its place, and the most important scoping information is front-loaded.

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 an output schema, read-only annotations, and sibling context, the description provides enough to select and invoke the tool correctly. It covers purpose, expected return content, source, authorization requirements, and the prerequisite relationship to SearchIAPDFirm.

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 description highlights the key parameter, crd, and tells the agent where to obtain it (from SearchIAPDFirm). However, it does not compensate for the remaining parameters such as wholesaler_ids, source_resource_id, exclude_fillers, or additional_display_fields, despite the reported low schema description coverage of the top-level schema.

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 names a specific verb and resource: 'Retrieve the full Form ADV filing detail for one RIA firm by its CRD number.' It also enumerates the fields returned, such as client types, custody information, and affiliated entities, which clearly distinguishes it from sibling lookup/search tools like SearchIAPDFirm.

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 contains explicit 'Use this tool when' bullets covering the main scenarios and names SearchIAPDFirm as the source of the required CRD. It does not explicitly say when NOT to use it versus alternatives such as GetIAPDIndividualDetail, so it stops just short of a full 5.

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