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

Annotations already declare read-only, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new behavior: a no_kit fallback for unsupported indices, a licensing gate for real-money settlement, a 'not advice' disclaimer, and a 600-character cap on the paste output. No contradiction with annotations.

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 body is one enormous run-on sentence enumerating roughly fifteen returned fields inside the same breath as the usage guidance. The use case is front-loaded, but the middle is an undifferentiated field glossary that is hard to scan and would be better as a structured list or deferred to an output schema.

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?

With no output schema, the description carries the burden of describing the return shape, and it does enumerate question, period, strikes, settle_time_utc, settle_rule, tie_rule, fallback, proof, recount, license and paste. This is sufficient for an agent to know what it gets back, though the presentation density hurts usability rather than leaving gaps.

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% and the sole ticker parameter is fully documented in the schema (including the four supported tickers and the optional dollar sign). The description restates the ticker set without adding new syntax or format meaning, 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?

The opening clause states a clear triggering condition and verb ('list, write or settle a prediction market') and names the resource (a Tickerz index market kit), plus an endpoint equivalence (GET /api/indices/{ticker}/listing.json). It is distinguishable from get_index/get_question because it produces a pasteable market rather than raw data, though the purpose statement is nearly swallowed by the following field dump.

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 when-to-use trigger ('when someone wants to list, write or settle a prediction market on a Tickerz index') and a boundary case ('Any other index returns no_kit with the reason'). It stops short of naming which sibling to use instead (get_index, get_rule, methodology) for adjacent needs, so it is clear context without alternative routing.

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