we_preview_open

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

Annotations already declare readOnlyHint=false and destructiveHint=false, so the agent knows this creates something non-destructively. The description adds real value by disclosing that results may be 'evidence or explicit unverified state' and that it 'never changes the desktop wallpaper'. It omits auth requirements and what a failed launch looks like, so it stops short of rich behavioral context.

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?

Two sentences, front-loaded with the action verb, and no filler padding. The trailing 'never changes the desktop wallpaper' clause is idiosyncratic and slightly wasteful, keeping it from a 5.

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 3-parameter creation tool with no output schema and zero schema descriptions, the definition leaves too much unsaid: parameter meaning, resolution constraints, and error behavior. The behavioral note is helpful but the definition is not complete enough for an agent to invoke it confidently.

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 0% and the description adds no information about width, height, or projectId — no format, units, defaults, or constraints. 'Immutable source snapshot' hints vaguely at the project reference but gives no actionable mapping, so the description fails to compensate for the undocumented schema.

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 clear verb+resource: 'Launch ... engine window from an immutable source snapshot'. An agent can tell this is the counterpart to we_preview_close. However, 'official engine window' is jargon-heavy, and the description never names the sibling or scopes itself against we_preview_observe/we_preview_set_properties.

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?

No explicit when-to-use or when-not guidance, no mention of prerequisites (e.g. requires a valid projectId), and no routing to alternatives such as we_preview_close for teardown. The phrase 'from an immutable source snapshot' implies a condition loosely but is not framed as usage guidance.

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