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

With no annotations provided, the description must carry the burden of disclosing behavior. It does mention that 'tagging mistakes [are] caught as you type', but this is vague—does it auto-correct, suggest fixes, or simply flag errors? It also doesn't state what the tool returns (presumably a modified URL) or whether it performs any validation beyond UTM components. The lack of an output schema makes this omission more serious. The brand mention 'A HelpySelf tool' adds no behavioral context.

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 extremely concise—two short sentences. However, the second sentence ('A HelpySelf tool (helpyself.com)') is marketing fluff that doesn't help an agent understand the tool's function. The first sentence is efficient and front-loaded, but the overall structure could be tighter by removing the brand reference.

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?

The tool is relatively complex (8 parameters, mutual dependencies for UTM tagging) and there is no output schema or annotations to fill gaps. The description only says it builds campaign URLs and catches mistakes 'as you type', which suggests an interactive form but doesn't explain the output format, the meaning of any parameters, or how mistakes are handled. For a tool like this, the description is severely under-specified.

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 coverage is 0%, so the description must explain the meaning of all 8 parameters. It fails to do so. While UTM parameters like source, medium, campaign, etc. are standard, the tool includes 'normalise' (a boolean with default true) and 'id' and 'term' whose roles are not obvious even to a seasoned marketer. The description provides zero parameter-level detail, leaving the agent to guess or rely on external knowledge.

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 purpose: 'A UTM builder for campaign URLs' with a specific verb and resource. It also adds a distinguishing feature ('tagging mistakes caught as you type') that sets it apart from a generic URL builder. Since none of the 100+ sibling tools specialize in UTM construction, this tool is unambiguous.

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 implies the tool is used when you need to create campaign URLs with UTM parameters, but it doesn't provide explicit guidance on when to use it versus alternatives (e.g., when you need tracking for ads or email campaigns). There's no mention of prerequisites, such as needing a valid base URL, or circumstances where another tool might be better. The guidance is purely implicit.

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