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

No annotations are provided, so the description carries the full burden of disclosing behavior. It only states that the destination URL is updated; it does not mention permissions, validation, irreversibility, side effects, or response behavior. This is minimal disclosure for a mutating operation.

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 a single, front-loaded sentence with no filler. Every word adds meaning: it states the action, the target, and the scope ('existing short link').

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 update tool with fully described parameters, this is minimally viable but not rich. The absence of annotations and an output schema means side effects, error conditions, and return behavior are left unspecified, though the core operation is clear.

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 input schema already has full descriptions for both parameters, covering 100% of them. The description does not add any parameter-level meaning beyond what the schema provides, so the baseline of 3 applies.

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 ('update') and a precise resource ('target destination URL of an existing short link'), making the tool's function immediately clear. It also distinguishes itself from siblings like create_short_link and update_alias by naming the particular property being modified.

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 intended use is implied: when an existing short link's destination URL needs to be changed. However, there is no explicit guidance about when not to use it or how it relates to update_alias, so the agent must infer the appropriate choice from sibling names.

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