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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, and the description adds context annotations cannot express: the return payload (puzzle number, word length, empty board) and the explicit guarantee that the answer is never returned. It also clarifies that date selection depends on the supplied time zone, a real behavioral trait of the call.

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?

Three tight sentences, front-loaded with the trigger condition, then behavior, then the next-step pointer. No filler and nothing buried.

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 zero-required-parameter, read-only starter tool with no output schema, the description covers purpose, return shape, time-zone semantics, and the follow-up path. Nothing needed to invoke it correctly is missing.

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 each parameter is already fully documented. The description's time-zone guidance ('pass when known... otherwise UTC') mirrors what the schema says rather than extending it, so the baseline 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?

States a specific verb and resource ('play today's Words With Attitude puzzle'), explains the game mechanic (guess a hidden word in six tries), and distinguishes it from the sibling submit_guess by naming that tool as the next step. An agent can tell exactly what this tool initiates.

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 an explicit trigger ('Use this when someone wants to play today's puzzle'), explains the time-zone preference and the UTC fallback, and names the follow-up tool (submit_guess) for subsequent guesses. When-to-use, default behavior, and the alternative are all covered.

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