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

Annotations already declare readOnlyHint=true and idempotentHint=true, covering the safety profile. The description adds value by specifying that query parameters are 'decoded' and by enumerating the output components. It does not discuss error behavior for invalid URLs, but the annotations lower the bar, and the added decode detail justifies a 4 rather than a 3.

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 tight sentences. The first sentence front-loads the action and output components; the second gives practical usage context. No wasted words.

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?

This is a simple one-parameter, read-only tool with an output schema and supportive annotations. The description covers purpose, usage context, and the nature of the result (decoded query parameters). Nothing essential is missing for an agent to select and invoke it correctly.

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?

Parameter schema coverage is 100%: the 'url' parameter is described as 'absolute, with scheme,' which aligns with the description's use of 'URL.' The description does not add any new parameter-level meaning beyond what the schema provides. Baseline of 3 is appropriate.

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 uses a specific verb ('Break') and resource ('a URL'), and explicitly lists the output components (scheme, host, port, path, decoded query parameters, fragment). This clearly distinguishes the tool from sibling utilities, which are entirely different (base64, datetime, etc.).

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 gives explicit context for when to use the tool: 'Use to inspect or debug a URL instead of parsing it by eye.' It doesn't name an alternative tool, but among the siblings there is no obvious conflicting URL parser, so this guidance is sufficient. A dedicated 'when not to use' clause is absent, which prevents a 5.

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