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

With no annotations, the description carries the full burden and does real work: it declares the operation is non-destructive ('Nothing is scheduled') and that no purchase occurs. It also previews what the response contains (numbers, objective, calls/day, window, estimated credits per call/day), which matters because there is no output schema. Permissions/auth requirements are not mentioned.

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 tight sentences, front-loaded with the dry-run nature, then the previewed outputs, then the two key constraints. Every clause earns its place and nothing is repeated padding.

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 10-parameter, no-annotation, no-output-schema tool, the description covers safety and return contents but leaves four parameters unexplained and says nothing about permissions or what the preview does once confirmed. Adequate to call correctly-ish, but not complete.

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 60%, and the description echoes the field groups it covers (numbers, objective, calls/day, window) without adding format or default detail beyond the schema's own descriptions. Parameters such as timezone, talking_points, exclude_weekends and max_call_duration_seconds get no mention in either place, so the description neither compensates nor adds much.

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?

States a specific verb and resource: a dry-run preview of enabling the phone channel for a campaign, with numbers the account already owns. The preview/activate pairing against siblings like activate_campaign_phone and preview_activate_campaign_linkedin is clear from the name plus 'Dry-run', though the description never names those siblings explicitly.

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?

'Dry-run' plus 'Nothing is scheduled' tells the agent this is the safe pre-flight step before activation. 'Numbers cannot be bought through the API' steers the agent toward owned numbers (list_phone_numbers) rather than a purchase path. It stops short of an explicit 'use this before X, use activate_campaign_phone to actually enable it' routing statement.

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