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

Annotations already cover read-only, idempotent, and non-destructive, so the description adds value beyond them by disclosing 'not separately rate-limited' and by describing the return contents (status, progress, timestamps, poll_url). No contradiction with annotations.

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 sentences carry the action, sibling pointer, rate-limit note, and return summary in efficient order. Every clause earns its place; no filler or repetition.

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 single-parameter, read-only status tool with strong annotations, the description covers the safety profile, rate limiting, return content, and the relevant sibling for blocking behavior. Nothing an agent needs to call it correctly is missing.

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% and the single job_id parameter is already documented as 'UUID of the async job'. The description adds only the context that this is a status fetch 'by id', which does not materially extend the schema's meaning. Baseline 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 uses a specific verb ('Fetch') and resource ('async simulation job status by id'), and scopes it as 'latest'. It also names sibling poll_job as a different behavior, so an agent can immediately distinguish this from related job 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?

Explicitly states the alternative: 'Use poll_job to block until a terminal state.' This tells the agent when to choose the sibling instead. It also implies suitable use for non-blocking status checks, though it stops short of a full when-not-to-use list.

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