Start Rust locally on an allowed client

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

Annotations already flag a non-readonly, destructive, open-world, non-idempotent call, and the description adds real behavioral context beyond that: the call is asynchronous (returns a job ID promptly), the build never executes main, and no downloads occur implicitly. It does not cover failure modes, timeouts, or whether a started job can be cancelled, which keeps it below 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?

Short, dense, and front-loaded with the action and its source of truth. A few phrases are telegraphic jargon ('Manifest-free std/local modules only') that cost a beat to parse, but there is no filler.

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 destructive, asynchronous job-starter with no output schema, the description covers the essentials an agent needs: where the inputs come from, that the response is only an acknowledgement, and that success must be confirmed via polling. Gaps remain around permissions, cancellation, and the meaning of 'target', but the operational contract is largely complete.

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 0%, so the description carries the burden. It usefully establishes provenance for sourceRevision ('exact ... from runtime_clients') and constrains operation ('explicitly allowed'), but the 'target' parameter (a bare 64-hex string) is never mentioned, and the four enum values are not explained.

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 ('Start one explicitly allowed operation on the exact runtime source revision') and pins the operation set (check/build/run/debug). It explicitly distinguishes itself from the sibling that supplies inputs (runtime_clients) and from the one that reports outcomes (poll job status / runtime_job).

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 clear context: inputs must come from runtime_clients, operations must be explicitly allowed, and only manifest-free std/local modules qualify (no implicit download, no private project inputs). It also prescribes the follow-up step ('Poll job status separately'). It stops short of naming the exact sibling tool to call next or stating outright when not to use this tool.

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