填滿一個長方體

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

Annotations already include `destructiveHint=true` and `idempotentHint=true`. The description goes beyond those by specifying the Bedrock per-operation limit of 32768 blocks and the meanings of `mode=hollow` (only outer shell) and `mode=outline` (only border), which are not in the annotations. This adds valuable context, though it does not elaborate on other mode effects like `replace` or `destroy`.

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?

The description is two sentences, front-loaded with the core purpose and immediately followed by the key usage constraint and mode clarifications. There is no filler or redundant repetition of schema or annotation content.

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?

Given that an output schema exists and annotations cover destructive and idempotent behavior, the description adds the most critical operational detail: the block count limit and the alternative tool for exceeding it, plus the hollow/outline mode semantics. It does not explain the full set of mode values (e.g., replace/destroy/keep), but those are standard Minecraft commands and partly described in the schema.

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 around 57%. The description compensates for the `mode` parameter by explaining the hollow and outline options, and it clarifies that the `block` parameter applies the same block across the whole volume. However, it does not add detail for coordinate modes or the replace-related parameters, leaving some meaning to the schema descriptions.

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 states a specific verb (fill) and resource (a cuboid from `from` to `to`) and clarifies that it uses a single block type. It also distinguishes itself from the sibling `mc_build_shape` by calling out the size threshold, which helps an agent separate the two tools.

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 explicitly says that when the fill exceeds 32768 blocks, the agent should use `mc_build_shape` instead, which automatically batches. This is a clear when-not/alternative rule, and it implies that `mc_fill` is appropriate for fills within the limit.

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