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

Annotations already declare a non-read-only, idempotent, non-destructive write, and the description adds genuinely useful context beyond them: existing domains are skipped, and background research is gated by plan, engine availability and research limits. What is missing is any statement of the failure modes (invalid domain formats, exceeding the account limit) and what the call returns.

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?

Three tight sentences, front-loaded with the action and the input format before the caveats. Every sentence carries information; the plan/engine/limits clause is slightly dense but not padding.

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 one-parameter write tool with no output schema and covering annotations, this is close to complete: input format, deduplication and limit behavior are all stated. The remaining gap is the outcome of a call (how many were added versus skipped, and what happens when the plan limit is hit).

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% and there is a single parameter, so the schema already carries the burden. The description does add the domain format via the example ('acme.com' rather than a full URL), which is the one piece of semantics the schema lacks, but it does not clarify whether subdomains or paths are accepted.

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 gives a specific verb and resource ('Add companies to your list by website domain') plus a concrete example array, so the action and input form are unambiguous. It does not name a sibling to contrast with, and request_accounts in particular sounds close enough that a differentiating sentence would help.

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?

Usage is implied rather than stated: an agent can infer this is for onboarding new companies onto the list, and the duplicate-skip note hints at when it is safe to call. There is no explicit when-to-use/when-not-to-use guidance and no mention of the alternative (request_accounts) for companies that are not yet on the list.

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