open_3d_url

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

The description goes well beyond the annotations (readOnlyHint=false, openWorldHint=true, destructiveHint=false) by detailing the network request and redirect behavior, no CORS requirement, size limits (256 MiB default, 1 GiB max), timeouts (30s socket, 120s transfer), and cleanup (temporary files deleted when scene closes). It also discloses that login/cookies and webpage extraction are not supported, and that external resources are not fetched implicitly. This is thorough and consistent with the annotations.

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?

The description is a single well-organized paragraph that front-loads the primary action and then provides necessary details in a logical order: formats, network behavior, parameters, limits, and cleanup. Every sentence contributes substantive information—there is no filler or redundant restatement of the tool name or schema.

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?

Given that an output schema exists (so return format is covered), the description addresses all essential aspects: input types, network semantics, limits, parameter usage, and lifecycle (temporary file deletion). It also mentions supported formats and gzip. An agent has everything it needs to decide when to use this tool and how to invoke it correctly without additional assumptions.

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?

With 0% schema description coverage, the description compensates by explaining key parameters: filename is for extensionless/signed URLs, scene_id is to append to an existing scene, and max_bytes has a default and maximum (256 MiB / 1 GiB). It also clarifies that url can be a single string or an array. This adds meaning beyond the raw schema types and defaults, though it does not explicitly describe the url parameter's expected format beyond 'direct HTTP(S)'.

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 states a precise verb (download and open) and resource (HTTP(S) 3D files), and clarifies that it creates a scene or appends to one via scene_id. It clearly differentiates from sibling open_3d_files by focusing on remote URLs and network behavior, while explicitly noting that external resources are not fetched implicitly. This gives an agent a distinct mental model of the tool's role.

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 description provides implicit usage context: it is for direct file URLs, not for webpage extraction or authenticated resources, and recommends self-contained models. It mentions that external resources are not fetched implicitly, implying that local files should go to a different tool, but it does not explicitly name alternatives or give hard when-to-use vs. when-not-to-use rules. Still, the guidance is clear enough for an agent to select it for URL-based 3D content.

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