preview_url

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

With no annotations, the description carries the full burden, and it does disclose the return payload (embed URL + thumbnail URL). However, it says nothing about auth requirements, whether the returned URLs are signed/expiring or stable, or any rate limits — meaningful gaps for a URL-issuing tool.

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 what is returned and followed by the use case; nothing is redundant. The second sentence is slightly soft ('Useful when...') but still earns its place as routing guidance.

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 simple one-parameter read tool with no output schema, the description adequately states the returned values and the intended scenario. It lacks only secondary details (URL stability, auth) that would make it fully self-contained.

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 100% and the single 'look' parameter is already documented as 'Preset id.' The description only restates 'a single preset' and adds no format, validity, or sourcing detail beyond the schema, so the baseline 3 applies.

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?

Names a specific verb (get) and precise outputs (canonical live embed URL and thumbnail PNG URL) scoped to a single preset, so the agent knows exactly what comes back. It hints at sibling differentiation by contrasting with building a 'full share URL' (build_share_url), though it doesn't name the sibling outright.

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 a clear use context: 'when you want to render an inline preview without building a full share URL,' which implicitly routes away from build_share_url toward this tool. There are no explicit exclusions, prerequisites, or named alternatives, so it stops short of the top band.

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