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

Annotations already declare a safe read (readOnlyHint, destructiveHint=false, openWorldHint=false), and the description adds meaningful semantics beyond that: fee-inclusive per-ticket dollars, one point per day, oldest first, and the crucial caveat that an empty history is a legitimate and common result because XP only records tracking events. Minor deduction because some return-shape detail overlaps with the existing output schema.

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-loads the usage triggers, then the return shape, then the disambiguation and the empty-history caveat. Four sentences, each carrying distinct information with no repetition of schema or annotations.

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?

Given a read-only two-parameter tool with an output schema and full annotation coverage, the description supplies exactly the missing pieces: intent triggers, price semantics (asking vs sold), and the empty-vs-flat distinction that an agent would otherwise misread as an error.

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 both `days` (1-90, default 30) and `event_id` (from search_market or search_events) fully documented in the schema. The description adds no parameter-level detail such as interaction between the days window and the empty-history behavior, 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 (retrieves daily closing get-in price history for an event) and defines the granularity and ordering: one point per day, oldest first. It also draws an explicit boundary against the sibling get_recent_sales by contrasting asking price over time with actual sold prices.

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?

Opens with concrete user-intent triggers ('are prices rising or falling', 'buy now or wait', 'what has this event been doing lately'), and names the alternative tool get_recent_sales with an explicit warning not to conflate the two. When-to-use and when-not-to-use are both covered.

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