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

Annotations already indicate readOnlyHint=false and destructiveHint=false. The description adds useful behavioral context: campaignId is derived when omitted, the tool returns the full updated/created object, and space scoping behavior. No contradictions detected.

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 purpose and contains no filler. However, it repeats the full role enum which is already in the schema, slightly adding length without new information. Still, it remains efficient and well-organized.

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?

Given the tool's moderate complexity and lack of an output schema, the description covers essential information: return value, scope rules, ID derivation, and space scoping. It does not cover error cases or edge behaviors, but those are beyond the typical expectation for this context.

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 100% top-level coverage, but the description goes beyond by explaining the conditional requirement of adId vs adGroupId based on scope, listing all role values, and clarifying that campaignId can be omitted. It also explains the space_id override parameter's effect, providing semantics not in 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 tool's function: attaching an existing asset to an ad or ad group with a specific role. It distinguishes itself from sibling tools like attach_asset_to_campaign by explicitly mentioning the AD/AD_GROUP scope and noting this is the scope that actually serves images/video.

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 clear guidance on when to use AD vs AD_GROUP scope and explains the practical relevance ('actually serves images/video on Display, Performance Max and Video campaigns'). It also notes campaignId derivation and active Space handling, giving clear context for invocation. Does not explicitly name a sibling alternative but the distinction is implied.

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