introspect_schema

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

With no annotations, the description carries the burden of disclosing behavior. It clearly indicates this is a read operation ('Fetch'), but it does not elaborate on potential caveats such as response size, rate limits, or whether authentication is required. It adds minimal context beyond the verb.

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 consists of two short sentences: the first states the purpose, the second explains when it's useful. Every word carries meaning, and the structure is front-loaded with the essential information.

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 tool with no parameters and no output schema, this description is largely complete: it tells what the tool does and why you'd use it. It could be slightly more explicit about the output format (e.g., that it returns a GraphQL schema in SDL or JSON), but given the low complexity, it suffices.

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 tool has zero parameters, so there is no parameter semantics to explain. Per the evaluation rules, a baseline of 4 is appropriate when parameters are absent, and the description does not need to compensate for any schema gaps.

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 states a specific action and resource: 'Fetch the full Railway GraphQL schema.' It clearly distinguishes from siblings by noting it's for discovering operations beyond the built-in tools, which sets it apart from raw query tools like raw_graphql.

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 phrase 'Useful for discovering available operations beyond the built-in tools' provides clear context on when to use the tool. However, it does not explicitly name alternatives or state when not to use it, unlike the ideal case where alternatives are mentioned.

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