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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds real value beyond that: the data source (SEC IAPD public API) and the fact that no API key is required, plus a summary of what the response contains.

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-loaded with the core action in the first sentence, then a bulleted usage block and a one-line source note; nothing is padded. The bullets are slightly repetitive with the opening sentence but earn their place as routing cues.

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?

An output schema exists, so return values need not be spelled out, and the description nevertheless summarizes the ADV Part 1 sections returned. Source, key requirement, and prerequisites are all present; only the auxiliary request parameters are left unexplained.

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 only speaks to the CRD ('by its CRD number'), which the schema already documents with an example and provenance. The remaining nested parameters (wholesaler_ids, source_resource_id, exclude_fillers, etc.) are not addressed in the description at all; the $defs entries do describe them, so the description adds little beyond the structured fields.

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 ('Retrieve the full Form ADV filing detail for one RIA firm by its CRD number') and enumerates the payload (client types, advisory activities, fee arrangements, custody, offices, affiliates). This cleanly separates it from the sibling SearchIAPDFirm search tool, which is named as the upstream source of the CRD.

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?

An explicit 'Use this tool when:' block gives three concrete conditions (you have a CRD, you need offices/custodians/affiliates, you're building a prospect profile), and it names SearchIAPDFirm as the prerequisite source. It stops short of stating when NOT to use it (e.g., individual reps belong in GetIAPDIndividualDetail), so it is strong but not fully routing.

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