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

Annotation Contradiction: The description states 'Create' which implies a write/mutation operation, while annotations declare readOnlyHint=true. This is a fundamental inconsistency that leaves the agent unable to trust either the description or the annotations.

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 a single, front-loaded sentence with no filler words. It earns its place by stating the core action, though it could be slightly more informative without losing conciseness.

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?

The tool has only one parameter and an output schema, so the basic shape is simple. However, the contradiction between the 'Create' description and readOnlyHint annotation leaves the behavioral contract ambiguous, which is a significant completeness gap.

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%, and the sole parameter 'description' is already documented in the schema. The tool description adds no meaningful semantic detail beyond what the schema provides, so the baseline score 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 clearly states a specific verb ('Create'), a concrete resource ('custom Last Frame world'), and the input basis ('from a description'). This distinguishes it from sibling tools like list_last_frame_worlds or start_last_frame.

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?

No guidance is given about when to use this tool versus alternatives such as list_last_frame_worlds, choose_last_frame, or start_last_frame. The verb 'Create' implies some usage context, but no explicit conditions, exclusions, or alternative routing are provided.

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