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

Annotations already declare readOnly/idempotent/non-destructive, and the description goes well beyond them: it discloses input validation rules (letters only, matching answer length), that invalid guesses are rejected with a reason and do not count, that the answer is revealed only on a win or the sixth miss, and that the server persists nothing — consistent with the idempotent hint and explaining why prior guesses must be resent.

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?

Five tight sentences: usage and prerequisite front-loaded, then the return shape, then the validation rule, then the answer-reveal condition and statelessness. No sentence is filler.

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 six-parameter, stateless tool with no output schema, the description covers what to send, what comes back (per-letter marking plus a comment), rejection behavior, and when the answer appears. An agent has everything needed to call it and to interpret results correctly.

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%, including the ordering semantics of previous_guesses and the time-zone fallback, so the schema does the heavy lifting. The description reinforces the required trio (puzzle number, prior guesses in order, new guess) and the letters-only/length rule, but never mentions time_zone or utc_offset_minutes, adding little genuinely new parameter meaning.

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 action (submit each word the player guesses) tied to a specific product and puzzle type, and names the sibling tool start_daily_puzzle that must precede it. An agent can immediately tell this is the per-guess play step, not the puzzle-creation step.

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?

Explicit usage cadence ('for each word the player guesses') and a prerequisite (puzzle started with start_daily_puzzle) plus the instruction to resend earlier guesses in order. It stops short of naming when to call the sibling give_up instead, so the alternative case is left implicit.

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