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

Annotations already declare destructiveHint=true and non-idempotent, so the safety profile is covered; the description adds only the ownership precondition. Critically, it never explains which numbers end up in the pool — the schema has no numbers parameter at all — so the core behavior of the call is left ambiguous.

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?

A single short sentence with no filler, which is well front-loaded, but the brevity comes at the cost of substance rather than being earned conciseness.

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 mutating, destructive-flagged creation tool with no output schema and only one-third parameter coverage, the description leaves key questions unanswered: how numbers are associated with the pool, what happens to a number already in another pool, and what is returned.

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 coverage is 33%: only `routing` is documented, and its enum description is thorough. `name` and `description` have no explanation in schema or description, and the description mentions no parameters at all, so it does not compensate for the coverage gap.

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 gives a specific verb and resource ("Create a sender pool") and adds the constraint that the pool is built from owned numbers, which separates it from clone_number_pool and update_number_pool. It doesn't explicitly name those siblings, but the intent is 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?

There is no statement of when to use this versus clone_number_pool or update_number_pool, no prerequisite about needing purchased numbers first, and no note that numbers must later be attached. The only implied guidance is "numbers you own," which is a precondition rather than a usage rule.

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