Attach numbers to campaign

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

Describes the response format as 'per-TN assigned/failed lists' with specific failure reasons, and notes that the response is NOT wrapped in the standard envelope. This adds significant context beyond the annotations, which only indicate non-readonly and non-idempotent. No contradiction with annotations.

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 with no wasted words. Front-loaded with action, then flow context, then response/error details. Every sentence earns its place.

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 parameter set and the presence of annotations, the description fully covers purpose, usage context, prerequisites, response format, and error scenarios. No gaps identified.

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 100% with clear descriptions for both parameters. The description adds context by explaining the campaign ID source (msg_list_campaigns / msg_create_campaign) and the NANP format example, which enhances understanding beyond the schema alone.

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 name and description clearly state 'Attach telephone numbers you own to one of your 10DLC campaigns.' It uses a specific verb ('attach'), identifies the resource ('telephone numbers' and 'campaign'), and positions it as step 3 of the 10DLC flow, distinguishing it from siblings like msg_remove_numbers.

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?

Explicitly states it is step 3 of the flow, lists prerequisites (msg_create_brand, msg_create_campaign), and notes that it is required before msg_send. Also enumerates possible error types (INVALID_PAYLOAD, NOT_FOUND, TNIQ_ERROR) with HTTP status codes.

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