Change a world

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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=false, so the agent knows this is a mutating but non-destructive, non-idempotent call. The description adds useful partial-update semantics ('only what you give changes') and clarifies that `respawn` changes the server-wide spawn point. It doesn't cover persistence requirements (does the world need saving?), permission needs, or failure behavior for conflicting inputs.

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?

Densely packed but front-loaded, with each sentence addressing a distinct parameter cluster. Some sentences are long and stack multiple facts (e.g., the `border` sentence), but nothing is plainly redundant.

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 an 11-parameter, nested-object mutation tool with no output schema, the description is thorough for nearly every parameter. The main gap is operational: persistence/save implications and interaction rules (e.g., passing both `dayTime` and `addTicks`, or both `spawn` and `respawn`) are not stated.

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 only 55%, so the description carries real weight and does so well: it explains `dayTime` tick values with concrete anchors (sunrise/morning/noon/night/midnight), `addTicks` as an alternative, `durationTicks` at 20 per second, the shape and an example of `rules`, what `border` subfields accomplish, and the critical distinction between `spawn` (this world's point) and `respawn` (the server's spawn point).

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 ('Change' a 'world') and immediately scopes it as a partial update ('only what you give changes'). It also distinguishes itself from the sibling get_world by noting that get_world with `include rules` lists game rules.

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?

Gives a clear operating model: pass only the fields you want to change, with concrete context for each domain. It stops short of explicit 'when not to use' guidance or routing to alternatives such as world_effect or save_worlds after mutation.

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