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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), and the description goes meaningfully beyond them by disclosing the authentication requirement and the asymmetric error behavior: invisible creator-deployed markets are explained only to the bound creator wallet while others get MARKET_NOT_FOUND. The example fragments add scenario context, though they are telegraphic rather than fully explanatory.

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 purpose sentence is front-loaded and efficient, but the 'Examples' block is a series of semicolon-joined fragments that read as status labels rather than complete examples, making them harder to parse than a short bulleted outcome list would be.

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?

An output schema exists so return values needn't be explained, and annotations cover safety. What remains uniquely useful — auth requirement, creator-only visibility disclosure, and the MARKET_NOT_FOUND fallback — is present, leaving only the sibling differentiation as a gap.

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% with only two required parameters (marketAddress, chainId), both already documented in the schema with format constraints. The description adds no additional meaning about parameter format or coupling, so 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?

The description gives a specific verb and resource ('preflight: whether a market is visible and tradeable') plus a scope qualifier ('creator-authenticated'), which separates it from generic existence checks. It does not name the closely related siblings (kellian_check_market_exists, kellian_get_market_state), so an agent must infer the distinction rather than being told directly.

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?

It states a clear usage context — a preflight check that a visible live market 'can proceed to forecast and quote' — and describes the negative outcomes (event over, no more trades, MARKET_NOT_FOUND). It stops short of explicitly naming the alternative market-existence and market-state tools or saying when not to use this one.

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