contactList

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

With no annotations, the description must carry behavioral disclosure. It does reveal the conditional behavior of the optional contact_id parameter, but it does not state whether results are paginated, what data is returned, or any rate-limit/auth implications. The read-only nature is implied by 'List' but not explicitly assured.

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 sentence front-loads the main operation and then adds the optional lookup variant, with a link to API reference. No filler or repetition of schema details.

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 tool with one optional parameter and no output schema, the description covers the two invocation modes clearly. It does not mention pagination or return structure, but those gaps are minor given the tool's simplicity and the embedded API reference link.

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 schema describes contact_id only as 'Contact profile ID'. The description adds that this parameter switches the tool from listing all profiles to fetching a single one, giving the agent actionable semantic context beyond the 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 opens with a specific verb and resource ('List contact profiles') and adds a clear alternative mode ('fetch one by contact_id'). This distinguishes the tool from CRUD siblings like contactAdd, contactUpdate, contactDelete, and non-contact list tools such as listDomains.

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 makes the core usage explicit: list all contact profiles unless a contact_id is supplied, in which case return a single profile. It does not name alternatives or state when-not-to-use, but the intended context is clear for a read operation among contact management siblings.

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