get_main_lines

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

Annotations already convey a safe read-only, idempotent operation. The description adds value beyond that by disclosing that retrieved_at is not price freshness, that pages are metered, and what data is preserved (participant identity, line value, price updated_at). These are meaningful behavioral notes not present in the 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 description is three concise sentences, each serving a distinct purpose: the action, the call-order constraint, data semantics, and operational cautions. It is front-loaded and contains zero filler, making it efficiently readable by an agent.

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?

The description covers the essential aspects: when to call, what data is returned (participant, line value, timestamps), and operational constraints like metering. It lacks a detailed return format description and explicit pagination details, but given the tool's simplicity and that the data-property hint implies the return structure, it is reasonably complete.

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?

The description adds context for event_id (must originate from list_events) and market_ids (explicitly request live markets 41/42/43), going slightly beyond the schema's descriptions. However, page and limit lack schema descriptions, and the description only hints at pagination through the metering note without explaining those parameters. Given the 60% coverage, it partially compensates but not fully.

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 clearly states the action (Fetch), the resource (open per-affiliate main lines), and the scope (for one event_id). It distinguishes itself from siblings like list_events and list_markets by its specific focus on main lines, leaving no ambiguity about what the tool does.

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?

The description provides explicit guidance: only call after list_events returns the exact ID, don't treat retrieved_at as price freshness, request live markets 41/42/43 explicitly, and be mindful of page metering. It lacks an explicit 'when not to use' or alternative tool mention, but the context is sufficient for correct invocation.

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