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

Annotations already declare destructiveHint=true, idempotentHint=false, and non-read-only. The description adds value beyond that by constraining the mutation surface ('Only `visible` can be changed') and disclosing the admin/feature authorization requirements. It does not explain what the response looks like, but the extra context is meaningful.

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 short sentences, front-loaded with the action and field constraint, then permissions. Zero filler; every sentence carries operational information.

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 narrow visibility toggle with annotations covering the safety profile and no output schema needed, the description covers purpose, field scope, and authorization. What it does not cover — the return shape or whether hiding affects campaigns — is minor for this tool.

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?

At 50% schema coverage, the nested `ad_account` object has no description in the schema. The description partly compensates by stating only `visible` can be changed, which aligns with the schema's `visible` field. It adds no format/syntax detail and leaves the object itself unclarified, so baseline 3 is appropriate.

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+resource ('Show or hide an ad account') and immediately scopes the mutation with 'Only `visible` can be changed.' This is clear enough to act on. It does not explicitly distinguish itself from related siblings like `list_facebook_ad_accounts` or `sync_facebook_ad_accounts`, so it falls short of a 5.

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?

Provides real gating context: 'Administrators only' and 'Requires feature: `facebook_marketing`' tell the agent when this call will succeed. There is no explicit statement of alternatives or when-not-to-use, so this is clear context rather than full when/when-not guidance.

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