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

With no annotations, the description carries the full disclosure burden and does so substantively: it states that rotatePairing signs the paired device out, that null stops answering callers, that the deployment caps concurrency overall, and that mode:live fails with LIVE_MODE_UNAVAILABLE. It omits any mention of the required revision parameter's optimistic-concurrency semantics and general permission requirements, keeping it short of a 5.

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?

Given 10 parameters and 0% schema coverage, the length is justified and every clause carries information. However, it is one comma-spliced run-on paragraph rather than a front-loaded summary followed by structured field notes, which reduces readability. Content is dense but not padded.

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 10-parameter mutation tool with no annotations and no output schema, the description covers most behavioral caveats but leaves the required revision parameter (optimistic concurrency) unexplained and says nothing about atomicity or partial-update behavior. It is adequate but has clear gaps for a tool of this complexity.

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 0%, so the description must compensate, and it does for most fields: name, isDefault, inboundAgentId, testNumbers, rotatePairing, capacity, and mode all receive meaning beyond the schema (e.g., SAGOT testNumbers removal-only, Twilio capacity limits, admin-only live mode). Only id, workspaceId, and revision are left unexplained, which is a minor gap for identifier fields.

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 enumerates the concrete operations performed on a line (rename, set default, set inboundAgentId, set testNumbers, rotatePairing, set capacity, mode:live), which clearly defines the tool's scope. It is distinguishable from siblings such as lines_create/lines_delete/lines_get, and it explicitly routes to lines.verifyNumber for adding numbers. It lacks a single summarizing verb+resource sentence, but the field-level enumeration conveys the purpose well.

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?

It provides strong conditional guidance: null inboundAgentId stops answering, SAGOT testNumbers can only remove (add via lines.verifyNumber), and mode:live requires admin not an assistant. It does not explicitly frame when to use this tool versus lines_create or lines_delete, but the operational conditions given are detailed and actionable.

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