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

Beyond the annotations, the description discloses sign-in requirements, owner approval prerequisite, active-plan requirement, pending-carrier behavior, status semantics for active versus connecting states, retry guidance via receptionist_refresh, and replacement restrictions. This is substantial behavioral context for an activation tool marked openWorldHint=true.

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 information-dense and every clause carries some behavioral meaning, but it is written as a long run-on with semicolon-separated rules and opens with constraints rather than a clear action sentence. The content is useful but would be easier to act on if structured into purpose, prerequisites, and status rules.

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 three-parameter activation tool with no output schema and no schema descriptions, the definition covers most operational concerns: authorization, approval, plan status, carrier pending state, retry behavior, and replacement restrictions. The main completeness gap is the unexplained mode parameter, which matters because the tool distinguishes new-number orders from other activation paths.

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?

With 0% schema description coverage, the description must carry parameter meaning. It usefully says to use a number from phone_numbers and ties owner approval to the owner_approved condition, but it never explains the mode enum values 'new' versus 'forward', leaving one of three required parameters ambiguous.

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 title and description make clear that this tool activates a chosen phone number, and it names related tools such as phone_numbers and receptionist_refresh. However, the description opens with preconditions rather than a direct action statement, so the core purpose is inferred from context rather than stated cleanly in the description itself.

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 gives explicit when-to-use conditions: owner-only, explicit owner approval of the exact number, an active receptionist plan, and the number must come from phone_numbers. It also gives when-not-to-use guardrails by forbidding replacement of pending, uncertain, ported, or routing-incomplete lines and by limiting another number to cases where can_choose_another_number is true after a fresh carrier check.

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