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

No annotations are provided, so the description carries the full burden. It clearly discloses the scope of the change (affects branded subdomain), reassures that plain short links remain functional, and mentions the Pro requirement. Though it does not detail the full request/response lifecycle, it provides sufficient transparency for a single-parameter mutation tool.

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 three short sentences that front-load the core action ('Claim or change the branded subdomain'), then add necessary constraints and reassurances. Every sentence adds useful information with no repetition or filler.

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?

Given the low complexity (single parameter, no output schema, no nested objects), the description is complete enough. It covers purpose, prerequisites, and a behavioral guarantee. The only minor gap is not stating the return value or success/failure cues, but for a mutation tool this is acceptable.

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 coverage is 100% with a clear description for the subdomain parameter. The description adds value by explaining the effect of the parameter ('so codes also resolve at {name}.oqr.to') and gives an example format. This goes beyond the schema's basic type/description, earning above 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 sequence ('Claim or change') and clearly identifies the resource (branded subdomain). It distinguishes itself from siblings like get_subdomain, clear_subdomain, and other domain-related tools, making its purpose unmistakable.

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 mentions 'Pro only' and 'Requires an OpenQR API key,' providing important prerequisites. It also clarifies a key context: changing the subdomain does not break existing short links. However, it does not explicitly state when to use set_subdomain versus siblings like bulk_create_dynamic_qr or other tools, but the context is clear enough for an AI agent.

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