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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description adds genuinely new behavioral facts: the projection is anonymous, data-only, and does not store a session, solution, or certification evidence. That non-persistence guarantee goes beyond the structured hints and matters for an agent deciding whether to rely on the call. Return-shape behavior is left unstated, so not a 5.

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?

Two front-loaded sentences with no filler; the core operation leads and the constraints follow. Minor issues: the 'up to24' typo and dense jargon ('public projection', 'certification evidence') slightly reduce 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?

There is no output schema, so the description reasonably needn't explain return values, and it does cover the non-persistence profile. However, with two undocumented nested-object parameters and zero schema coverage, the description leaves the agent without enough to construct a valid definition/gameplay_contract payload.

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 0%, so the description carries the full burden, yet it only illuminates two of the four params: 'one explicit author-chosen action' (action) and 'up to 24 prior actions' (prior_actions, matching the schema maxItems). The required 'definition' and 'gameplay_contract' objects are completely unexplained, leaving half the contract opaque.

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 names a specific operation: a 'draft simulation of exactly one explicit author-chosen action' with a bounded 'up to 24 prior actions' history. It is clearly a preview/simulation of a single author action rather than a persisted submission, though the phrase 'author step' and 'gameplay_contract' keep it somewhat opaque. It does not explicitly name the sibling it differs from (e.g. submit_author_action), so it stops short of a 5.

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 negation clause ('no stored session, solution, automatic action or certification evidence') implies when-not-to-expect-persistence, and the 24-prior-action framing hints at the intended scenario. But there is no explicit when-to-use vs alternative guidance telling the agent to reach for preview_author_step over submit_author_action or author_test_replay.

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