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

Annotations already disclose that this is a non-read-only, non-destructive, open-world operation. The description adds meaningful behavioral context beyond that: the 4.5-block reach limit, the requirement that the target cell be empty and adjacent to a solid block, and that the block comes from inventory. It still omits failure behavior and whether the item is consumed, but with annotations covering safety this is a solid addition.

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 short sentences, front-loaded with the primary action and then the key constraints. There is no redundant or filler text.

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 simple placement tool with rich annotations and fully described schema parameters, the description covers the core action and constraints well. It lacks detail on error conditions or item consumption, but no output schema exists and the missing pieces are relatively minor.

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 100%, so the schema already explains x, y, z, block, and api_key. The description adds only high-level context ("block from your inventory") and does not clarify formats or coordinate semantics beyond what the schema provides, so the baseline of 3 is appropriate.

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 and resource ("Place a block") along with concrete scope ("from your inventory within 4.5 blocks"). This clearly distinguishes the tool from siblings like mine, use, and craft, which manipulate blocks or items differently.

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 gives validity preconditions ("cell must be empty and touch a solid block") but does not say when to choose this tool over alternatives such as use or craft. Usage is implied by the constraints rather than explicitly guided.

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