x3d_list_defs

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

With no annotations, the description carries the burden. It explains return behavior and input flexibility, but doesn't explicitly state whether the operation is read-only or what error handling looks like. For a list operation, this is adequate but not rich.

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 structured with a clear summary, a brief explanation of DEF names, return details, and usage hint. It's a bit wordy with the HTML analogy, but all content is relevant and front-loaded.

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 relatively simple tool, the description covers purpose, input format, output contents, and usage context. An output schema exists, so return structure isn't needed in the description. Missing edge cases like invalid input, but not essential.

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?

The schema only says 'x3d_source' is a string, with no description. The description adds critical detail: it can be a file path or full XML document string, which significantly clarifies usage. This compensates well for the 0% schema coverage.

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 clearly states the tool's purpose: listing all DEF'd nodes in an X3D scene, with specific mention of returned context (node type, parent, children). This distinguishes it from siblings like x3d_search_nodes or x3d_node_info by focusing on DEF names as identifiers.

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?

Includes explicit usage context: 'Use this to find targets for x3d_extract_node or x3d_add_node', which signals when this tool is appropriate. It doesn't explicitly state when not to use it, but the related tools give some contrast.

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