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

Annotations already provide readOnlyHint=true, and the description does not contradict this. The description adds valuable behavioral context: the mutually exclusive required IDs (a constraint not reflected in the schema's required list), the Space scoping behavior, and how campaign_id expands the scope. It does not mention pagination or return format, but given the annotation coverage, the added context is significant.

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 two sentences long, front-loaded with the core purpose, then the critical constraint, then the scoping behavior. Every clause earns its place with no filler or redundancy. It is highly scannable and efficient.

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 7-parameter tool with no output schema, the description gives the essential selection rules and scoping mechanism. The main gap is that it does not describe what the response items look like (e.g., whether each binding includes full asset objects or just IDs), but this is not strictly required without an output schema. The description is sufficient for an agent to decide when to call the tool and set up valid parameters.

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 description coverage is 100%, so the schema already documents each parameter. The description adds essential semantic value beyond the schema by stating the 'exactly one of ad_id / ad_group_id / campaign_id' mutual-exclusion rule, which the schema does not encode. It also clarifies the space_id override behavior. This elevates it above the baseline 3 for high schema coverage.

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 tool 'List asset-to-ad / ad-group attachments', which is a specific verb+resource that distinguishes it from sibling tools like list_assets (which lists assets themselves) and list_campaign_assets. The added detail about campaign_id returning 'every ad-level binding' further disambiguates its scope.

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?

The description explicitly states the core usage constraint: 'Exactly one of ad_id / ad_group_id / campaign_id is required', and explains the behavior for campaign_id. It also directs users to set_active_space for switching spaces or passing space_id to override. However, it does not explicitly contrast with list_assets or say 'use this instead of X when you need bindings' — the distinction is implicit rather than explicit.

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