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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds domain context by enumerating the returned phone line details, but it doesn't disclose additional behavioral traits such as permissions, error cases (e.g., no phone line configured), or output format.

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?

The description is a single, efficient sentence that front-loads the resource ('The workspace's phone line') followed by a clear list of what is returned. Every element earns its place with no 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 simple read tool with one optional parameter, no output schema, and annotations covering safety, the description is largely complete by enumerating the returned fields. It omits edge cases (e.g., what happens if no phone line is set up), but that is a minor gap.

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% for the single optional project_id parameter, which is documented as 'Workspace to work in (from list_projects). Leave out for the default one.' The description adds no further parameter details, so the baseline 3 is 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?

The description clearly states the tool returns the workspace's phone line configuration, enumerating number, voice, inbound answering, greeting, and AI credits. This distinguishes it from sibling tools like get_call (call records) and get_settings (general settings) without explicitly naming them.

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?

No guidance is given on when to use this tool versus alternatives. The description implies it's for retrieving phone setup information, but it doesn't mention prerequisites, exclusions, or related tools like get_call or get_settings.

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