vrm_snapshot

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

With no annotations, the description carries the full burden. It discloses a key behavior ('through a local headless Chrome/Edge') and a limitation ('rest pose', though v0.1 supports only rest pose). However, it does not mention side effects like file overwriting, system requirements beyond the browser, or error behavior, leaving gaps for a render 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?

The description is a single, information-dense sentence with no fluff. It front-loads the core action and then lists key options, earning its place with relevant details.

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 render tool with no output schema, the description covers the essential behavior: input, output type (PNG), pose, expression, and view presets. It misses details about return values or error handling, but for a utility that writes to an output_path, this is acceptable. The 'local headless Chrome/Edge' requirement adds important operational context.

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 only 43%, so the description must compensate. It adds meaning to 'expression' (with an example) and 'view' (mentions face close-up), but it does not clarify 'width' or 'height' beyond their schema types. This partial compensation matches the baseline for a moderately described 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?

The description clearly states the action ('Render a still PNG'), the resource (a VRM avatar), and specific details like 'rest pose', 'expression weights', and 'view presets'. This distinguishes it from sibling tools like vrm_inspect (inspection) and vrma_preview (VRMA animation), making its purpose unambiguous.

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 implies when to use the tool (when a snapshot of a VRM is needed) but does not explicitly state alternatives or exclusions. It does not compare with sibling tools, so guidance is implied rather than explicitly provided.

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