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

Annotations already declare read-only, idempotent, open-world, non-destructive behavior, but the description adds substantial operational context: metered usage tied to the connected account, no background polling or automatic retry, affiliate 27 exclusion, empty results not implying lack of coverage, and no guarantee of returns. This goes well beyond what the annotations provide.

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 front-loaded with purpose and then gives usage and behavioral guidance in a compact paragraph. It is somewhat long and repeats some schema details, but most sentences add actionable context for a complex, chart-oriented endpoint.

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 the presence of an output schema and annotations covering safety and idempotency, the description supplies the remaining context an agent needs: participant discovery workflow, totals handling, main-line behavior, affiliate exclusion, metering, and retry expectations. Nothing essential appears missing for correct invocation.

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 schema itself already documents the nested path and query parameters in detail, including participant_id discovery, main_line, and affiliate_ids. The description largely repeats that schema content, adding only the note that series are grouped by affiliate and may contain points for more than one participant.

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 states a specific verb and resource: get line price chart data for a specific market, returning time-series data for charting line movement. It is clear what the tool does, but it does not explicitly differentiate itself from similar siblings such as v2GetMarketLinePriceHistory or v2GetMarketHistoryByEvent.

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 procedural guidance: discover participant_id via GET /api/v2/markets/participants first, and for totals discover TYPE_RESULT Over and Under participants and request each side separately. It also explains main_line filtering and affiliate exclusion, though it does not state when not to use this tool or name an alternative tool.

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