preview_character

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

With no annotations, the description carries the burden and does well: it discloses that no files are saved (non-persistent), and that the return type varies (animated GIF vs still image) based on the animated flag. It does not cover auth requirements, rate limits, or error behavior, and never explains what the required items input must contain.

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?

Front-loads what the tool does and keeps to four tight lines with no filler; each sentence carries information. Slightly terse in places (e.g., the items obligation), but nothing is wasted.

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?

No output schema and no annotations, so the description must fully carry the behavior. It adequately covers the animated/animation semantics and the non-saving nature, but omits any explanation of the required items argument or body_type, leaving real gaps for a 4-parameter 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 description coverage is 0%, so the description must compensate. It explains animated (True=GIF, False=still) and enumerates animation values (walk, idle, slash, run, 1h_slash, watering, oversized options), but says nothing about the required items parameter or body_type, leaving half the parameters undocumented.

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?

Specific verb (shows/preview) plus resource (the character) with explicit scope: the 4 directions side by side, rendered in chat and not saved to files. It distinguishes itself from the siblings by naming generate_character as the follow-up and implying this is a non-persistent look-see versus random_character/generate_character.

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?

"Use it to check the look before generate_character" gives a clear usage context and names the alternative tool the agent should follow with. It does not state explicit when-not-to-use conditions, but the preview-before-generate framing is unambiguous.

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