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

Annotations only say readOnlyHint=false and destructiveHint=false; the description adds that it saves data, that it's a prerequisite for change operations, and provides phone format (E.164) and country_code meaning. It doesn't detail repeated-call behavior, but the annotations already cover the safety profile, and the description adds useful context.

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 moderately long but every sentence adds value: purpose, alternative, format, and idempotency. It is front-loaded with the main action and ends with practical details. No unnecessary fluff.

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 simple save operation, it covers purpose, prerequisites, and parameter formats. It doesn't describe the return value, but an output schema exists, so that is not a gap. It could explicitly state that phone is optional if not provided, but the schema already shows defaults. Overall, it is adequately 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?

The schema has 0% description coverage, so the description must explain parameters. It does explain phone format (E.164) and country_code (dialing code), and implies first_name/last_name via 'full name'. However, it doesn't clarify that only first_name is required while phone and others are optional, which could cause confusion since it says 'saves ... phone number'. It still adds format details 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 clearly states the action (saves the account owner's full name and phone number) and its purpose (unlocking operations that change an ad account). It also distinguishes itself from read-only tools by explicitly stating it is not required for view/list/report tools, helping an agent pick the right tool.

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 gives explicit when-to-use guidance: it is needed to enable operations that modify an ad account (creating/updating/pausing campaigns, budgets, statuses), and it is not needed for read-only tools. It also mentions an alternative (panel) and states that calling once is enough, which is clear direction.

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