add_tile

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

Annotations declare this is a non-read-only, non-destructive, closed-world write, so the safety profile is covered. The description adds that the tile may be optionally filled and that the new index is returned, but says nothing about persistence, required layer type, or side effects on existing tiles.

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 tight sentences with zero filler; the core action is front-loaded and the return value is appended compactly.

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 4-parameter mutation tool with 25% schema coverage and no output schema, the description covers the return value but leaves 'filename' and 'frame' entirely unexplained and gives no guidance on the tileset/layer preconditions.

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 only 25%, and the description mentions just the optional colour fill. The required 'filename' and the 'frame' parameter (with its default) remain undocumented in both description and schema, leaving half the parameters semantically opaque.

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: 'Add a new tile to the layer's tileset', with the optional solid-colour fill noted. It is distinguishable from mutation siblings like set_tile/set_tiles, though it does not explicitly contrast itself with fill_tile or create_tilemap_layer.

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?

There is no statement of when to use this versus alternatives such as set_tile, fill_tile, or paint_tile_pixels, nor any prerequisite (e.g. layer must already be a tileset). Usage must be inferred from the name alone.

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