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

Annotations already declare the write profile (readOnlyHint=false, destructiveHint=false, openWorldHint=true, idempotentHint=false). The description adds that the resulting list is reusable across multiple workflows, which is light extra context, but it does not disclose non-idempotent behavior (duplicate lists on repeat calls) or any limits on how many filters/lists can be saved.

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?

A single front-loaded sentence that commits the verb and resource immediately with no filler or repetition. Every clause earns its place by naming the use cases.

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 create mutation with a deeply nested request body and no output schema, the description says nothing about what is returned (presumably a list object/ID) or about the __requestBody wrapper. Annotations cover safety, but the return/confirmation aspect is missing.

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% and the nested filter object is thoroughly documented in the schema, so the schema does the heavy lifting. The description only refers generically to 'a company filter' and adds no syntax or field-level meaning beyond it, making the baseline 3 appropriate.

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?

States a clear verb ('Save') and resource ('a company filter as a reusable list'), and the company-list scope implicitly separates it from contact_lists-create and company_lists-update. It does not explicitly name or contrast with a sibling, so it stops short of a 5.

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 downstream purposes (review, enrichments, scoring, export, CRM workflows) imply why an agent would create a list, giving useful context. However, there is no explicit when-to-use vs. when-not, no prerequisites, and no mention of the update/import alternatives.

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