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

The description discloses the condition for region creation ('if >= 5 blocks were placed') and the return format ('Returns {ok, region_created, regionId?, reason?}'), adding value beyond the annotations which only indicate readOnlyHint=false and openWorldHint=false.

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 concise (two sentences) and well-structured, front-loading the main action and then providing key details about side effects and return. No extra words.

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 tool with 2 required parameters, no output schema, and minimal annotations, the description provides sufficient behavioral context, including the condition for region creation and the return format, enabling correct agent invocation.

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 input schema already describes both parameters adequately (space as string, goalId as integer with description referencing set_goal). The description does not add parameter-specific information, so baseline score of 3 is appropriate given high schema coverage.

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 clearly states the action ('Mark your active build goal as completed') and explains the side effect of automatic region creation. It distinguishes itself from the sibling tool 'set_goal' by indicating this is the completion step.

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 tells when to use: 'Call this when you finish building the structure you declared in set_goal.' It does not mention when not to use or alternatives, but the guidance is clear enough.

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