List SIP trunk providers

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

The readOnlyHint annotation already signals a safe read operation, and the description adds useful context by scoping the list to the PBX and specifying the fields returned. It does not contradict the annotations and provides reasonable behavioral expectations for a simple no-parameter listing tool.

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 immediately states the action and resource, then immediately lists the returned fields. There is no filler or redundancy.

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 parameterless, read-only list tool, this description is complete: it names the resource, the scope, and the fields in the result. The annotations cover safety, and no output schema exists, but the description sufficiently sets expectations for a simple list operation.

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 tool has zero parameters and the schema coverage is effectively 100%, so there are no parameter semantics to document. The description's mention of returned fields is a useful bonus and meets the baseline for parameterless tools.

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 uses a specific verb ('List') and identifies the exact resource ('SIP trunk providers (upstream carriers) configured on the PBX'). It also enumerates the returned fields (name, host, tenant), which clearly distinguishes it from sibling list tools for other entities.

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 clearly states that this tool lists SIP trunk providers on the PBX, giving enough context for when to call it. It does not explicitly contrast it with siblings, but the resource type is distinct enough that no real ambiguity exists.

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