resolve_vanity_url

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

With no annotations, the description carries full burden. It discloses the authentication need (STEAM_API_KEY) and the return format, which is good. However, it does not explicitly state that the operation is read-only or handle error cases like invalid URLs, leaving minor gaps.

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 very concise: one sentence for the purpose, one for a requirement, and a structured return format. Every element 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 simple one-parameter tool with an output schema, the description covers the main functionality, authentication, and return format. It lacks error handling details, but overall it is sufficiently complete for an agent to understand usage.

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 provides a clear description for the only parameter (vanity_url) with an example, achieving 100% schema coverage. The main description adds no further parameter details beyond requiring an API key, so the baseline of 3 is appropriate.

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 action ('Resolve') and the resource ('Steam custom vanity URL to a 64-bit Steam ID'), making the tool's purpose unambiguous. It is distinct from sibling tools which handle game details, player summaries, or store searches.

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 a requirement (STEAM_API_KEY), which is a usage condition, but it does not specify when to use this tool versus alternatives or provide exclusions. Usage is implied rather than explicit.

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