build_mosaic

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

With no annotations, the description carries the full burden and does add non-obvious geometry semantics: orientation orientation and the plate/brick tradeoff. But it says nothing about whether the tool clears existing bricks, whether it requires an open/current model, how large a mosaic can be, or what happens on failure — significant gaps for a mutating build operation.

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 that front-load the purpose and then the orientation/kind semantics; nothing is wasted. The telegraphic 'image top = back' phrasing is compact but slightly cryptic without further context.

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 described. But for a 10-parameter mutation tool with zero annotation coverage and only two of ten parameters addressed, the definition is not complete enough to call confidently — placement, cropping, sizing, and limit behavior all remain opaque.

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% and 10 parameters are present, so the description must compensate. It does explain 'kind' and 'orientation' meaningfully, but x, y, z, crop, width, height, image_path, and max_colors receive no explanation at all — notably crop's expected format and max_colors' quantization behavior are left entirely 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?

States a specific verb and resource ('Build a picture directly as a mosaic in the current model'), which is concrete and actionable. It does not name or contrast with the closest sibling, image_to_grid, so an agent must infer the difference between building a mosaic directly and converting an image to a grid.

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 implicitly guides when to pick each orientation and kind value ('plate gives fine vertical detail, brick is sturdier'), which is useful selection guidance. However there is no explicit when-to-use-this-vs-alternatives statement, no mention of prerequisites such as needing an open model or how it relates to image_to_grid, and no exclusions.

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