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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description goes beyond them by disclosing the exact payload ( program, screenplay rendering, duration in seconds, settings with units) and by noting that moves come 'ready-made' and can be used as a starting point for authoring. It does not mention size limits or error behavior for an unknown move reference.

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?

Front-loaded with the return contents, then the naming rules, then the authoring workflow, then a call example. Every sentence earns its place, though the run-on enumeration of return fields is dense and could be split for readability.

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?

With no output schema, the description must carry the return contract, and it does — itemizing every field the agent will receive. Identifier formats and the follow-on validate step are covered. Missing only edge-case behavior (what happens if the reference is ambiguous or unknown).

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 100% and the schema already says the value is the id, short name or page slug as list_moves gives them. The description still adds real value by spelling out the three accepted forms and giving a concrete id example ('c4c:beh:wave_hello') plus a call example, removing any guessing about format.

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 ('Returns one ready-made move') and then enumerates exactly what comes back: block program JSON, screenplay text, length in seconds, works-on target, settings with units, page and links. The word 'one' plus the enumerations clearly separates it from the sibling list_moves.

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 authoring workflow: 'To write your own move, start from one, change it, then validate it,' routing the agent to the sibling validate tool. It also explains the three accepted identifier forms, but never states when not to use this tool or what to use instead for bulk retrieval.

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