creature_stats

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

With no annotations, the description carries the transparency burden. It discloses the return payload shape ({name, cr, xp, citation}) and a fallback behavior ('cannot-adjudicate otherwise'). It does not explicitly state side-effect-freedom or permissions, but 'Return' and the deterministic phrasing imply a read-only lookup.

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 two sentences, front-loaded with the action, and every clause adds information. There is no redundant or filler text, aside from minor stylistic quirks like 'legal with data'.

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?

The output schema exists and likely documents the return structure, so the description does not need to repeat that. It covers the core purpose and failure mode. However, the rich optional policy parameters are left entirely unexplained, which is a moderate completeness gap for an agent deciding whether to include them.

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 0% with six parameters, yet the description only implicitly mentions the 'name' parameter via 'known creature' and the output keys. It does not explain request_id, table_policy, asserted_facts, policy_context, or table_decision, or when these optional parameters should be supplied. This is a significant gap.

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 opens with a specific verb and resource: 'Return a creature's Challenge Rating and XP with a page citation.' It clearly states what the tool does and its purpose ('for deterministic encounter-budget math'), distinguishing it from sibling tools like encounter_xp_budget or creature_valid.

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 gives a clear context for use ('for deterministic encounter-budget math') and an explicit applicability condition ('for a known creature; cannot-adjudicate otherwise'). It does not name alternative tools, but the when/when-not boundary is apparent.

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