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

Annotations already cover the safety profile (readOnly, non-destructive), so the description's added value is the polling semantics and the 15-minute post-completion expiry — genuinely useful operational context the agent cannot infer from annotations. It stops short of disclosing error/intermediate states or what a completed result contains.

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 short sentences, front-loaded with the resource and follow-up with the polling and expiry rules; no filler. The opening phrasing ('a job that returned status running') is slightly awkward but does not waste words.

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?

With no output schema, the description never says what the fetched result contains (route geometry, legs, status field), which an agent needs to use the return value. Polling and expiry are covered, but the return payload is a real gap for a 2-parameter async-result tool.

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 0%, so the description must carry parameter meaning. It explains that wait_seconds bounds the wait ('Waits up to wait_seconds') but omits the 0–45 constraint, and job_id is only implied by the phrase 'an optimize_routes job'. Partial compensation for a zero-coverage 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 names a specific verb ('Fetch') and resource ('the result of an optimize_routes job') and ties the tool to its sibling optimize_routes, making the async-job relationship explicit. An agent can distinguish this from get_route_example/list_route_examples without opening any schema.

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?

It gives a clear usage pattern: call while status is 'running', wait up to wait_seconds, then call again. It does not, however, state when to prefer this over the sibling example tools or what to do once the job finishes, so an explicit exclusion is missing.

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