sleeper_exec

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

With no annotations, the description carries the full behavioral burden. It usefully discloses the Firefox limitation, but for an arbitrary-code-execution tool it says nothing about execution context (page vs. isolated world), side effects on page state, return value, or error/timeout behavior.

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 front-loaded sentence with no filler. It is efficient, though the extreme brevity borders on under-specification rather than disciplined conciseness.

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?

No annotations, no output schema, and two of three parameters undocumented. For a tool that executes arbitrary code, the description omits return format, execution semantics, and failure modes that an agent needs 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 coverage is only 33% — 'tab' and the required 'code' have no descriptions. The description adds no parameter meaning at all, so it fails to compensate for the coverage gap, leaving the agent to guess what 'tab' accepts.

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 gives a specific verb and resource ("Execute arbitrary JS") plus the execution environment (Chromium), which no sibling tool duplicates. It stops short of explicitly contrasting with the closest relative, sleeper_api, so the agent must infer which to reach for.

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?

The only conditional guidance is a platform limitation ("unavailable in signed Firefox builds"). There is no statement of when to prefer this over sleeper_api or sleeper_batch, no prerequisites, and no exclusion cases.

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