Google Ad Manager MCP Server

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

With no annotations provided, the description carries full burden. It states this is a creation operation but doesn't disclose behavioral aspects like required permissions, whether this is a mutating operation with side effects, rate limits, or what happens if validation fails. The description mentions default values but doesn't explain creation consequences or error handling.

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?

Well-structured with clear sections (purpose, Args with detailed parameter explanations, Returns). While comprehensive due to many parameters, each sentence adds value. The line_item_type enumeration is necessary but makes it somewhat dense. Front-loaded with the core purpose first.

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 complexity (11 parameters, creation operation, no annotations) and the presence of an output schema (so return values don't need description), the description is mostly complete. It thoroughly documents parameters but lacks behavioral context about permissions, side effects, or error handling that would be important for a creation 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?

With 0% schema description coverage for 11 parameters, the description provides extensive parameter documentation beyond the schema. It explains each parameter's purpose, provides examples (e.g., end_year format, creative_sizes JSON format), lists valid line_item_type values with explanations, and specifies defaults where applicable, fully compensating for the schema's lack of descriptions.

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 creates a new line item for an order with the verb 'Create' and resource 'line item'. It distinguishes from siblings like 'update_line_item_name' or 'duplicate_line_item' by specifying it's for creation, but doesn't explicitly contrast with all alternatives like 'create_order' or 'create_campaign'.

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?

No guidance on when to use this tool versus alternatives like 'create_order' or 'duplicate_line_item'. The description mentions prerequisites (order_id, target_ad_unit_id) but doesn't provide context about appropriate scenarios or exclusions for this specific creation operation.

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