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

With no annotations, the description carries the full burden and does meaningfully: it discloses determinism ('Repeatable with a seed'), the output encoding ('Returns the PNG base64 encoded'), and the cost ('1 credit per call'). It stops short of covering size limits or failure behavior, but the core behavioral profile is present.

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?

Four short sentences, front-loaded with the core purpose and followed by the three facts an agent needs (determinism, return format, cost). No filler.

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 exists, and the description usefully compensates by stating the return is a base64 PNG, plus it discloses cost. However, for a tool whose four tuning parameters (size, scale, octaves) directly determine the result, the absence of any parameter guidance leaves a real gap.

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% for four parameters, so the description must compensate and largely does not. It only touches 'seed' (via 'repeatable with a seed') and hints at octaves through 'layered'; size, scale, and octaves semantics and their ranges are left entirely unexplained.

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 ('Generate a greyscale heightmap PNG from layered value noise') plus concrete domains (terrain, clouds, textures). This clearly separates it from image siblings like pixel_art, sprite_sheet, or color_palette.

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 'for terrain, clouds or textures' clause implies when the tool is appropriate, but there is no explicit when-not guidance and no named alternative for adjacent tasks. Usage is inferable but not directed.

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