assign_carrier_subscriber_plan

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

With no annotations, the description carries the full burden, and it does disclose the mutation gate: confirm must be true to apply, and dry_run previews without applying. That is genuinely useful behavioral context, but it omits permission requirements, reversibility, and what a preview actually returns.

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 purpose sentence is front-loaded and efficient, but the Args/Returns docstring block is boilerplate and the Returns line restates what the output schema already provides. It is adequately sized but not tightened.

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 5-parameter mutation tool with no annotations, this covers the core operation and the confirm/dry_run gate, and the output schema handles return values. The missing 'controller' semantics and the phantom 'settings' entry leave the definition incomplete for correct invocation.

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 only 20%, so the description must compensate, and it documents subscriber_id, plan_id, confirm, and dry_run (including the required-unless-dry_run rule). However it introduces a 'settings' parameter that does not exist in the schema and never mentions the real 'controller' parameter, leaving one parameter fully undocumented.

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 first line states a specific verb and resource: assigning a service plan to a UniFi Carrier Fabric subscriber. It is clear what the tool does, though it does not distinguish itself from the nearby update_carrier_subscriber sibling, so an agent could confuse the two.

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 guidance on when to use this tool versus update_carrier_subscriber, create_carrier_subscriber, or the plan-listing tools. The dry_run/confirm mechanics imply a preview-then-apply workflow but the description never states it as usage guidance or names alternatives.

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