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

Annotations already declare destructiveHint=true, readOnlyHint=false and openWorldHint=true. The description adds behavior beyond that: signal defaults to SIGTERM and SIGKILL terminates the entire process tree, the long-poll nature of waitMs (holds the call up to 8000ms), and the stdinMode/pty prerequisite for write. It still omits what 'list' returns or the meaning of state/exitCode.

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?

Dense but organized action-by-action with the critical scoping fact (process must come from exec background:true) front-loaded. Every clause carries information; the only nit is that the single long sentence is somewhat run-on and could be split for scannability.

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 an 8-parameter, multi-mode tool with no output schema, the description covers the action semantics well but is incomplete: eof and processId are never mentioned, the id vs processId relationship is unexplained, and the read-state/exitCode values are named without defining them.

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 only 13% (8 params, essentially one described), so the description must carry the load. It does add real meaning for cursor ('pass the returned nextCursor next time'), waitMs ('up to 8000 holds the call until there is output'), data and signal (SIGTERM default, SIGKILL for the whole tree), but leaves eof, processId and the required id/processId distinction completely unexplained.

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 ('Work with a process started by runtime_sandboxes_exec background: true') and enumerates the exact operations (read, write, signal, list). It explicitly ties itself to the sibling runtime_sandboxes_exec, so an agent can tell which tool starts a process and which one follows it.

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 for each action and a precondition for write ('the process needs stdinMode pipe or a pty'), plus the routing hint that the process must have been started with exec background: true. It lacks explicit when-not guidance or a direct alternative comparison, but the usage context is solid.

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