Release a number

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

Annotations already declare destructiveHint=true, but the description adds valuable context: the number leaves inventory and may be picked up by others, and lists specific error conditions (TN_NOT_OWNED, POI_LOCKED, TNIQ_UPSTREAM_ERROR). This goes beyond the annotation's bare flag.

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 three sentences: first states purpose, second warns and gives usage guidance, third lists errors. It is concise, front-loaded, and every sentence adds value. No wasted words.

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?

Given the simple action (release a number) and no output schema, the description covers the key aspects: purpose, irreversibility, and errors. It omits details like return value or success indication, but for this tool, those are less critical.

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 100%, so the baseline is 3. The description does not add new information about parameters beyond what the schema already provides (tn and reason). It mentions errors but not parameter specifics.

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 clearly states the verb 'Release' and the resource 'a telephone number you own back to inventory'. It distinguishes this action from sibling tools like num_get, num_list, or num_update_*, all of which are non-destructive or have different purposes.

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 explicitly warns that the action is irreversible and advises confirming with the user. It also lists specific errors, providing context for when the tool may fail. However, it does not compare with alternative tools or specify when not to use it.

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