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

Annotations already carry the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower, yet the description adds real context: no persistence or billing side effects, build diagnostics are returned, and HTTPS imports are not bundled (browser-only). It does not describe size/file-count limits or failure behavior, which would be the remaining useful additions.

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?

Purpose and side-effect scope are front-loaded, and the sentences are dense and largely non-redundant. The final sentence about window.HostedWorld is tangential API guidance that does not help select or invoke this tool, costing a bit of focus.

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 read-only tool with full annotation coverage and no output schema, the description covers purpose, side effects, and return intent adequately. However, a deeply nested, zero-documented parameter plus build constraints mean an agent still lacks guidance on how to shape a valid 'site' payload, leaving a real completeness gap.

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% and the single 'site' parameter is a nested object with four required/optional fields (entryPoint, category, files, assets) plus nested variants and assets. The description only gestures at the payload ('local modules and HTML pages') without explaining entryPoint, category, assets, or the difference between files and assets, so it compensates very little for the undocumented nested structure.

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 ('Compile the complete local HTML/CSS/JavaScript site package') and immediately distinguishes itself from the sibling save_hosted_world_site by scoping out side effects ('without saving, publishing or paid effects'). An agent can tell what this does and what it does not do without opening the schema.

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 'without saving, publishing or paid effects' clause clearly signals the safe pre-flight context in which this tool should be used versus the save/publish siblings. It stops short of an explicit routing statement (e.g. 'call this before save_hosted_world_site'), and the closing sentence about window.HostedWorld is runtime guidance rather than tool-selection guidance.

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