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

Annotations already declare readOnly, idempotent, non-destructive, so the safety profile is covered; the description adds what annotations cannot, namely the polling lifecycle, that exactly one of `response` or `error` is populated on completion, and that the id remains readable afterward. It omits what an in-progress or not-found response looks like, which keeps it from a 5.

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 tight sentences: identity and scope first, then the polling loop, then the terminal outcomes and id persistence. No filler, and the actionable timing instruction is placed before the result semantics.

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 tool with an output schema and strong annotations, this covers the decision-relevant behavior: how to call it, how often to call it, and when to stop. Only edge cases such as an expired or unknown operation id are left unaddressed.

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% and the schema only constrains `operation_id` to a non-empty string, so the description carries the parameter burden and does so by documenting the two acceptable id formats. That is genuine meaning beyond the schema, though it gives no guidance on what to do if a malformed id is supplied.

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 the resource (a long-running operation) and the lookup key (by id), and spells out the two accepted id forms `op_…` and `operations/op_…`. It does not explicitly contrast itself with a sibling, but the polling semantics make its role distinct from the list/create tools in the catalog.

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 concrete usage context: use this for work that outlasts a call, with sandbox placement and x402 settlement as examples, and prescribes a polling cadence of about every 2 s until done. It stops short of naming an alternative tool for cases where the work completes synchronously, which is the only missing routing cue.

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