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

Annotations already cover the safety profile (readOnlyHint, destructiveHint=false, openWorldHint=false), and the description adds genuinely new behavior: returns status first and the result only 'once available', so a caller knows a partial/not-ready response is possible, plus the contrast with run_simulation's blocking semantics. It stops short of covering error cases for an unknown run_id or any retention/expiry behavior, so not 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?

Purpose is front-loaded in the first clause, and the usage caveat follows immediately. Slightly padded: the JSON example largely restates the one-parameter schema, and the run_simulation caveat is packed into a long parenthetical that takes a second read.

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 an output schema present, return values need not be described; annotations cover safety; the single parameter is fully documented. The description supplies exactly the missing pieces — when to call it and that results may not yet be available — leaving no gap an agent needs to close before invoking it.

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 description coverage is 100% and the single run_id parameter is documented as 'A run id returned by run_simulation'. The description's example call shows the ID's string shape, which is marginally additive, but otherwise the schema carries the load — the baseline 3 applies.

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?

States a specific verb and resource ('Fetches the status and ... the summarised result for a previously-submitted run by its run_id') and explicitly distinguishes itself from run_simulation, the sibling an agent would otherwise confuse it with. The scope — retrieve an existing run, no resubmission — is unambiguous.

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?

Gives both the positive case ('re-check or re-fetch a run you already submitted') and the exclusion ('run_simulation itself already blocks until done ... so this is not a poll-until-ready step for it'). That is an explicit when-to-use plus a named alternative and its disqualifying condition.

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