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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=true and destructiveHint=false, so the safety profile is covered. The description adds genuine context beyond that: the runners are client-side, and they come in browser-sandbox and self-hosted sealed variants. It does not describe what a returned entry contains or whether runners must be registered or authenticated before use.

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?

A single short sentence with no filler, and the distinguishing detail (client-side, sealed, two runner types) is front-loaded. It loses a point only because the sentence is a fragment with no verb, which weakens the action statement rather than the economy.

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 zero-parameter read-only list with no output schema and rich annotations, most of the burden is already carried by structured fields. Still, the description leaves open what the listing returns per runner and whether these environments are something the agent registers, claims, or simply runs in, which matters given the surrounding bounty/registration siblings.

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?

The tool takes zero parameters, so the schema leaves nothing to explain and the baseline is 4. The description introduces no parameter-like concepts that would need clarification.

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 defines the resource well ('client-side sealed execution environments agents can run bounty work in') and even enumerates variants (browser sandbox, self-hosted sealed runners), but it never states the operation. It is a noun phrase with no verb, so the 'list' behavior is only inferable from the tool name 'runners_list' and the annotation title 'List Sealed Runners' rather than from the description itself.

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?

There is no explicit when-to-use guidance, no prerequisites, and no reference to any alternative or follow-up tool. The parenthetical hints at use for bounty work, but it does not say whether an agent should call this before wide_agent_register or wide_claim, or what to do with the result.

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