List campaign numbers

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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false. The description adds error codes (NOT_FOUND, TNIQ_ERROR) and clarifies the scope (numbers attached to a campaign). It does not contradict annotations and provides additional useful context beyond the structured fields.

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 two sentences: first sentence clearly states the purpose, second sentence gives usage guidance and error codes. Every sentence adds value; no fluff. It is front-loaded and efficiently structured.

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?

There is no output schema, so the description should compensate by explaining the return structure. It mentions listing numbers but does not describe the response format (e.g., paginated list, fields). For a simple read-only tool, it is adequate but could be more complete by indicating what the response contains.

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 significant meaning beyond what the schema already provides for each parameter. It reinforces the context (campaign numbers) but doesn't elaborate on parameter formats or constraints.

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 specific action: 'List the telephone numbers attached to one of your 10DLC campaigns.' It includes the verb 'list' and the resource 'telephone numbers attached to a campaign'. It also distinguishes from the sibling tool msg_list_numbers by specifying when to use each.

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 provides explicit guidance: 'Use to verify which numbers can send under a campaign; for account-wide messaging status of every DID use msg_list_numbers.' This tells the agent exactly when to use this tool and when to use an alternative. Errors are listed.

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