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

With no annotations present the description carries the full burden and does so richly: it discloses the refusal condition, the Twilio/SAGOT cascade (deletes trunk, credentials and origination URL it created), that detached numbers remain the caller's property, that finished-call history is retained, that scheduled retries are skipped, and that a default line is reassigned. This is exactly the kind of side-effect disclosure a destructive operation needs.

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 core action is front-loaded in the first sentence, followed by terse, high-value clauses on refusal, side effects and post-conditions. Every sentence adds information, though the paragraph is dense and the unexplained term "SAGOT" costs a little clarity.

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 destructive tool with no annotations and no output schema, the description covers refusal conditions, cleanup cascade, data retention and default reassignment well. It stops short of stating permission/auth requirements or whether the operation is idempotent, which leaves a small residual 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?

Two required UUID parameters (id, workspaceId) have 0% schema description coverage, and the description never mentions either parameter or explains which identifier the agent must supply. The description does not compensate for the coverage gap, leaving the agent to infer the required inputs.

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?

Opens with a specific verb+resource ("Remove a phone line") that is unambiguous and clearly distinct from the sibling mutation tools lines_create, lines_update, lines_clearAlert and lines_test. An agent can route to it without inspecting the schema.

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?

Provides an explicit precondition/exclusion: the call is refused while the line has active calls, which tells the agent to cancel calls first. It does not, however, name any alternative tool or explain when a different operation (e.g. deactivating via lines_update) would be preferred.

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