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

readOnlyHint=true already tells the agent this is a safe, non-mutating read, so the lower bar applies. The description adds the scope ('this room's blocks') and hints that results are keyed by number, but says nothing about ordering, completeness, or how the mapping is presented.

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?

One short, front-loaded sentence with no filler. It is efficient, though brevity comes at the cost of stating the action verb, which makes it slightly cryptic rather than crisp.

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?

With no output schema, the description carries the burden of explaining the return value, and 'by number' only partially signals that the result is a number-to-name mapping. For a zero-parameter lookup this is roughly adequate but leaves the return shape and the enclosing scope implicit.

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?

The tool takes zero parameters, so there are no parameter semantics to document and the baseline of 4 applies. Nothing is missing here.

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?

The description identifies the resource (the texture name/number mapping for a room's blocks) but never states the action — whether it lists, resolves, or returns them. It doesn't differentiate itself from texture-adjacent siblings like paint_faces, place_blocks, or look_blocks, so the agent can't tell exactly what operation this performs without inference.

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 when-to-use guidance, no mention of prerequisites (e.g. needing to be in a room), and no reference to alternatives such as look_blocks. The agent must guess the context in which this is the right call.

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