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

Annotations already mark this as read-only, idempotent, and non-destructive. The description adds genuinely new behavioral detail: an unknown run_id fails with not_found, and the response shape is spelled out (run_id, recommended_action, confidence, expected_value, mode, created_at). This gives the agent a clear model of both success and failure behavior.

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?

Three sentences with no filler: the core purpose is front-loaded, then usage guidance, then failure behavior and return fields. Every sentence earns its place.

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 one-parameter fetch tool, the description is complete: it explains how to find the ID, what the call returns, and what happens when the ID is invalid. No output schema exists, so describing the return fields is essential and properly handled.

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 already describes run_id as a 'UUID of the simulation run,' giving 100% schema coverage. The description adds value by connecting run_id to the discovery workflow ('Use list_runs to find run ids') and by listing run_id in the return record, reinforcing its role as the lookup key.

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 verb and resource: 'Fetch one simulation run by run_id with its full detail.' It also clarifies scope by naming the included content (decision metrics and request context) and distinguishes it from list and other get_* siblings by naming the exact resource type.

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 gives clear context for when to use the tool—when a single simulation run's full detail is needed—and explicitly tells agents to use list_runs to find run ids. It does not explicitly enumerate exclusions versus other get_* tools, but for a simple one-parameter fetch it provides adequate guidance.

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