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

Annotations already declare this a safe read, so the description adds genuine behavioural context: an empty result is a meaningful answer (no verified transfers in the window), the data is completed deals rather than asks, and results include time-since-clear. The caution against generalising from a single sale warns about interpretation risk that no structured field conveys.

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 trigger condition is front-loaded and each sentence carries a distinct payload: trigger, return contents, empty-result meaning, decision use, interpretation caveat. Slightly long for a one-parameter read tool, with the final caveat bordering on advisory padding, but nothing is redundant.

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 single-required-parameter read tool with annotations and an output schema, the description covers the only things structure cannot: when to reach for it, that empty means genuinely no trades, and how much to read into a thin result. Nothing an agent needs to call or interpret it is missing.

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% and the single event_id parameter is fully documented there, including its source (search_market or search_events). The description adds only indirect meaning ("on an event") and no format or scoping detail beyond the schema, 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?

States a specific verb and resource — recent completed deals from the XP marketplace with per-ticket price and time since clearing — which clearly separates it from listing/offer tools. It does not name a sibling explicitly (e.g. get_price_history, get_ticket_listings), so differentiation is inferred rather than stated.

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?

"Use when the user asks what tickets actually sold for" is an explicit trigger, and "before claiming nothing has traded" plus "before deciding whether to make an offer or wait" give clear decision contexts. It never names an alternative tool to use instead, so the when-not/alternative half of the guidance is left implicit.

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