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

With no annotations, the description carries the full burden, and it discloses meaningful behavior: changing the destination redirects all existing printed copies, click history is preserved, new destinations are screened with Google Safe Browsing, and the short code is immutable in this operation. It leaves minor gaps around response/error behavior, but the core side effects and constraints are well covered.

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 front-loaded with the main action, and every sentence earns its place: operation, real-world implication, safety screening, immutability constraint, and authentication requirement. It is detailed without being wordy or redundant.

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 mutating tool with no annotations and no output schema, the description is unusually complete: it explains side effects, constraints, screening behavior, and the required plan. It does not mention the response shape or failure cases, but an agent has enough context to select and 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 coverage is 100%, so the schema already documents every parameter. The description adds only high-level framing—such as 'new destination' for url and UTM switchability—and does not materially expand on the schema's own descriptions. This matches the baseline for fully covered schemas.

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 opens with a specific verb ('Re-point... or change') and a named resource ('existing short link'), and enumerates the mutable fields: destination, title, description, and UTM parameters. It also clarifies what the tool does not do (changing the short code), which distinguishes it from sibling operations. The title reinforces the resource without being relied upon.

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 a concrete use case—repurposing printed QR codes—and states the Business-plan API key prerequisite. It does not explicitly name an alternative tool for changing the short code or creating a new link, so it stops short of a full when-to-use/when-not-to-use guide. The context is clear, but exclusions are only implied.

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