Resolve vanity URL to SteamID

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

Annotations provide readOnlyHint and openWorldHint, which are consistent. The description adds the requirement for an API key and specifies the output format (17-digit SteamID64), which is valuable beyond the annotations. No contradictions.

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 two sentences, each serving a purpose: the first explains the core functionality, the second adds an important requirement. No unnecessary words, well-structured.

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 conversion tool with one parameter, no output schema, and clear annotations, the description fully covers what an agent needs: input format, output description, and prerequisites (API key). It is complete for the tool's complexity.

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 covers the single parameter with 100% coverage, providing a description. The description adds a concrete example ('gabelogannewell') and explains its context from a URL, which adds meaning beyond the schema.

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 tool converts a vanity profile name to a SteamID64, specifying the part of the URL and the output format. It distinguishes itself as a prerequisite for other player tools that need the SteamID64, which sets it apart from sibling tools.

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 implies usage when you have a vanity URL and need the numeric SteamID, and it explicitly notes the requirement for STEAM_API_KEY. However, it does not explicitly state when not to use it or mention alternatives, which is acceptable given no alternative exists among siblings.

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