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

Annotations list all hints as false, indicating no special flags, but the description adds key behavioral details: no authentication required, the 24-hour expiration, and the redirect mechanism. This goes beyond the annotations to clearly set expectations.

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?

Three concise sentences: states the core function, gives usage context, and warns about the 24-hour limit. Every sentence adds value, with no fluff.

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 single-parameter tool with an output schema and annotations, the description covers purpose, usage, and constraints comprehensively. No gaps remain for expected behavior.

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 covers 100% of the parameter (long_url) with a clear description and format. The tool description does not add extra parameter-level detail, but the schema already provides sufficient meaning. Baseline of 3 is appropriate given full schema coverage.

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: turning a long URL into a short 307.fi link that redirects. It uses a specific verb-resource combination and differentiates itself from siblings by highlighting the temporary nature and direct usage.

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?

Explicitly states when to use the tool (e.g., when a URL needs to be typed or pasted in constrained contexts) and when not to use it (for anything lasting over 24 hours). It also provides a clear alternative guidance by labeling it for handoffs within tasks, distinguishing it from other tools.

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