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

Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false, so the safety profile is clear. The description adds behavioral context by disclosing that the tool returns all market variants for an event, including alternate lines and props or all outcomes, which is not visible from annotations. It stops short of describing response structure or pagination, but the core behavior is transparent.

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?

Two sentences carry all needed information: what the tool does, what result categories to expect, and when to call it. The most important action is front-loaded and there is no filler.

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-parameter tool with safe read-only annotations, the description is nearly complete: it names the input source, the return content categories, and the intended position in the workflow. It lacks a response/pagination note, and with no output schema that would be the only remaining gap for an agent invoking it correctly.

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 schema description already tells the agent that slug is the 'Event slug from a market result (eventSlug field).' The prose only repeats 'by event slug' without adding new parameter semantics, so the baseline of 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 opens with a precise verb and object: 'Fetch every market for a single event by event slug,' which clearly separates it from broad search tools. It further specifies market composition (moneyline, alternate spread/total, props) and multi-outcome events, leaving no ambiguity about the tool's scope.

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 gives explicit when-to-use guidance: 'Use after swop_search_markets when the user wants full detail on one game/event.' This establishes the intended sequence and scenario, though it does not spell out when not to use it or name other alternatives besides swop_search_markets.

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