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

Annotations already declare this a safe, read-only, open-world read. Beyond that, the description discloses genuinely useful behavior: what an empty result means ("no verified transfers in the window") and an interpretive caution ("One sale is one sale -- do not generalise from a single clear"). It doesn't cover rate limits or fetch-window size, keeping it at a strong 4.

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?

Front-loaded with the triggering condition, then the return shape, then edge-case semantics, then decision context. Each sentence mostly earns its place, though the closing "One sale is one sale" line is more flavor than specification and adds slight length.

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 an output schema present, return fields need not be re-explained, and annotations carry the safety profile, so the description's remaining job is purpose, usage, and edge-case semantics -- all of which it covers, including the important empty-result interpretation. Nothing an agent needs to call this correctly 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 description coverage is 100% and there is exactly one parameter (event_id), whose meaning and source are already fully documented in the schema. The description adds no parameter-level detail, which is the expected baseline 3 when the schema does the heavy lifting.

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 precise verb+resource: recent completed deals (actual sold prices) from the XP marketplace, with per-ticket price and recency. It implicitly distinguishes itself from listing-oriented siblings (check_listing, get_ticket_listings) by framing the result as what "actually sold for" and adds scope via "verified transfers in the window." An agent can tell this apart from get_price_history without opening either schema.

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?

Multiple concrete when-to-use triggers are given: "Use when the user asks what tickets actually sold for," "before claiming nothing has traded," and "before deciding whether to make an offer or wait for a price drop." This is rich contextual guidance, but it never names a specific alternative tool (e.g. get_price_history) or states a when-not condition, so it falls short of the 5 bar.

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