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

Beyond the annotations, it discloses wallet charging behavior, paused-campaign charging semantics, auto-reload preconditions, untouched existing properties, and the exact skipped-property reasons in the response. These are material behavioral traits for a destructive, non-idempotent, open-world mutation.

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 front-loaded with the core action and cost impact, then proceeds through prerequisites, charging nuances, and response details in a logical order. Despite its length, every sentence carries operational information for a complex charging mutation.

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 complex, destructive campaign mutation with no output schema, the description covers prerequisites, cost approval, pause/resume charging, auto-reload conditions, and response fields including skipped reasons. It gives an agent enough context to invoke the tool safely and interpret its outcome.

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 75%, with descriptions for confirmed, recipient, and property_ids already present. The description adds useful workflow meaning around confirmed (user approval after estimate) and property_ids (count sent to estimate), though campaign_id is not elaborated beyond the schema.

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 uses a specific verb and resource ("Adds properties to a ... campaign"), states the wallet-cost consequence, and distinguishes this operation from campaign discovery and estimation via named sibling operations. An agent can immediately tell this is the mutation for adding properties to an existing mail campaign.

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?

It explicitly prescribes the prerequisite estimate call, user approval step, and campaign eligibility (Ready, Active, or Paused), plus how to find campaigns that accept properties with search_campaigns and accepting_properties=true. This gives clear when-to-use and when-not-to-proceed guidance.

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