render_image

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

Annotations already declare non-read-only, non-destructive, non-open-world, so safety is largely covered. The description adds two genuinely useful traits beyond that: writing to disk when path is set, format chosen by extension, and that ray tracing can take minutes. It says nothing about what happens when path is omitted or what transparency/viewport_pass do.

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 dense sentences, no filler, with the core action and settings scope front-loaded and the caveat (slow with ray tracing) at the end where it still reads. Slightly awkward semicolon chaining but nothing wasteful.

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?

An output schema exists, so return values need not be explained, and the disk-write and runtime behavior are covered. However, with seven parameters at 0% schema coverage, two parameters (transparency, viewport_pass) and the camera identifier format are undocumented, leaving real gaps for a moderately complex render tool.

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 0%, so the description must carry all seven parameters. It explains path (format by extension), width/height/sampling (default to render settings, implying the -1 sentinel) and camera (active or given), but transparency and viewport_pass are completely unaddressed and there is no hint of accepted camera identifier forms.

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 ('Render one image') plus the governing camera and render-object settings, which lets an agent distinguish it from the plural siblings render_images and render_videos. It stops short of explicitly naming those siblings, so differentiation is implied rather than stated.

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?

'Render one image' versus the sibling 'render_images'/'render_videos' hints at the single-vs-batch distinction, and the note about path writing implies when output goes to disk. There is no explicit when-to-use/when-not guidance, no prerequisites (active camera must exist), and no routing to alternatives.

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