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

With no annotations provided, the description carries the full behavioral burden. It discloses the key non-obvious trait: the URL is ephemeral and expires after 24 hours. It does not discuss slug conflicts or error handling, but the most important behavioral constraint is explicitly surfaced.

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?

One short sentence, front-loaded with the verb and resource, and immediately followed by the essential qualifier. Every word earns its place with no redundancy.

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 two-parameter create operation with an output schema present, the description covers the core purpose and the only notable behavioral constraint (expiration). Missing conflict-handling details are minor and not needed to select or invoke the tool 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?

Schema description coverage is 100%; both url and slug are already fully documented in the input schema. The tool description adds no parameter-level detail, so the schema carries the semantic weight, matching the high-coverage baseline.

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 ('Create') and resource ('short URL'), and adds the defining qualifier 'ephemeral ... expires after 24 hours'. This unambiguously distinguishes it from sibling tools delete_shortlink, resolve_shortlink, and shortlink_status.

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 clearly establishes the context: use this when you need a temporary short URL that self-expires. It does not explicitly mention alternatives, but the create-vs-manage distinction among siblings is obvious enough that an agent can infer when to use it.

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