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

Annotations already establish the safety profile (readOnlyHint=false, destructiveHint=true, openWorldHint=true), so the description's job is to add specifics — and it does: a 10-per-call cap and a hard one-restart-per-lifetime limit with rejection on retry. The rejection behavior is consistent with idempotentHint=true in that repeat calls produce no further state change, so no contradiction. It does not mention authentication, quota impact, or response shape.

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?

Three sentences, all front-loaded: the operation and its scope first, then the constraints, then the endpoint. No filler, and each sentence carries a distinct piece of information.

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 single-parameter write tool with no output schema, the description covers operation, limit, failure mode, and transport. What is missing is any hint of the response or what a rejected restart looks like to the caller, which an agent would have to discover empirically.

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?

Top-level schema coverage is 0% for the 'numbers' array, though the nested 'number' and 'carrier' fields are documented inline in the schema. The description compensates only partially by restating the batch ceiling ('up to 10 per call'), which matches maxItems, and says nothing about the number/carrier object shape or that carrier is optional.

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?

States a specific verb and resource ('restart tracking') and names the scope ('stopped numbers'), which cleanly separates it from stop_tracking, register_numbers, and change_carrier. The 'WRITE:' prefix and POST /retrack endpoint make the operation unambiguous.

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 precondition ('stopped numbers') tells the agent when this tool applies, and the once-per-lifetime rule warns when it will fail. It stops short of naming alternatives explicitly (e.g., use register_numbers for never-tracked numbers), so the routing guidance is contextual rather than spelled out.

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