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

With no annotations, the description carries the full behavioral burden. It usefully discloses that the fork is isolated and private and that the public axioms remain unaltered, but it omits permissions, whether the fork inherits all axioms, and what happens to the source world after forking.

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 definition is a single front-loaded sentence with no wasted words. The action and its rationale are both immediately clear.

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 creation tool with no output schema and no annotations, the description covers isolation and non-alteration well. It does not state what is returned (for example, the new fork's handle or ID), which is a meaningful gap when no output schema exists.

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 both parameters are already documented in the input schema. The description adds no extra meaning about the format of world_id_or_handle or any constraints on title, so the baseline of 3 applies.

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: "Create an isolated private fork of a public Small World." The trailing purpose clause ("so custom rules can be ingested without altering public axioms") implicitly separates forking from the sibling ingest_axioms tool, though it does not name that sibling explicitly.

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?

It gives a rationale for when forking is appropriate: custom rules can be ingested without altering public axioms. However, it does not explicitly say when to choose this over ingest_axioms directly, nor does it state prerequisites such as whether the source world must be public or whether the caller needs ownership.

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