Google Ads MCP Server

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

With no annotations provided, the description carries full burden for behavioral disclosure. While 'update' implies a mutation operation, it fails to mention critical aspects like permission requirements, whether budget changes are immediate or scheduled, rate limits, or what happens if the budget exceeds account limits. For a mutation tool with zero annotation coverage, this represents a significant gap in transparency.

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 perfectly concise at just 7 words, front-loading the essential action and resource without any wasted language. Every word earns its place, making it immediately scannable and understandable while avoiding unnecessary elaboration.

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 budget mutation tool with no annotations and no output schema, the description is insufficiently complete. It doesn't address what the tool returns (success confirmation? error messages?), doesn't mention side effects or constraints, and provides minimal guidance for proper usage. Given the complexity of financial operations and lack of structured safety signals, more context would be valuable.

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%, with both parameters clearly documented in the schema itself. The description adds minimal value beyond what's already in the structured data - it mentions 'daily budget' which aligns with 'budget_euros' but doesn't provide additional context about format, constraints, or business rules. This meets the baseline expectation when schema does the heavy lifting.

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 verb ('update') and resource ('daily budget for a campaign'), making the tool's function immediately understandable. However, it doesn't differentiate from potential sibling tools like 'enable_campaign' or 'pause_campaign' that also modify campaign states, leaving some ambiguity about when to choose this specific budget update 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?

The description provides no guidance on when to use this tool versus alternatives. There are no mentions of prerequisites (e.g., campaign must be active), exclusions (e.g., cannot update paused campaigns), or comparisons to sibling tools like 'get_campaign_details' for checking current budget first. This leaves the agent with minimal context for appropriate tool selection.

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