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

With all annotations false, the description carries the behavioral burden. It discloses defaults (name, number, date), mutual exclusion (parentId excludes sessionId), visibility restriction (playerIds), and authorization (GM-only). This goes beyond the minimal 'create' implication, though it doesn't cover failure modes or idempotency.

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 dense paragraph with no filler. It front-loads the core action, then clearly separates required, optional, and authorization details. Every sentence adds necessary information about how to call the tool correctly.

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 create operation with an output schema, the description covers all needed context: required vs optional parameters, defaults, exclusivity rules, visibility, and caller restrictions. Nothing an agent needs to invoke it correctly is missing, and the output schema handles return-value documentation.

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 is empty, so the description is the only source of parameter information. It lists every parameter with defaults, constraints, and relationships (e.g., parentId excludes sessionId). This fully compensates for the absent schema and earns the highest score.

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: 'Record a new play-by-email move on a campaign.' This clearly distinguishes it from sibling tools like play_update_move, play_delete_move, and play_get_move, which concern modifying, deleting, or retrieving 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?

The description provides clear context: it is for creating a new move, requires campaignId, and is GM-only. It does not explicitly name alternatives for editing or listing moves, but the 'new' qualifier and required/auth conditions give strong contextual guidance.

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