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

With no annotations provided, the description carries the full burden. It reveals that execution is local/runtime-only, but does not disclose potential side effects, auth requirements, error behavior, or response format. While it gives the execution scope, it lacks deeper behavioral traits.

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?

Two concise sentences that front-load the action. Every sentence adds necessary information without redundancy or fluff.

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?

The description covers the core purpose, usage context, and parameter format adequately for a straightforward tool. However, since there is no output schema, the lack of return value description is a minor gap, though not critical for a simple function execution.

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% with adequate parameter descriptions. The description adds value by specifying that args can be a JSON object, array, scalar, or null, reinforcing the schema. However, it does not significantly extend beyond what the schema already communicates.

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 executes a local-runtime Mojo library function by module and function name. It uses specific verbs and resource, and distinguishes itself from sibling tools like list_runtime_libraries and get_runtime_modules by focusing on execution.

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 explicitly notes that this tool is local/runtime-backed and does not route through hosted data/query APIs, providing clear context for when to use it versus hosted alternatives. However, it does not explicitly list when not to use it or name specific alternative tools.

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