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

Annotations already declare read-only, idempotent, non-destructive behavior, but the description adds meaningful operational context: data comes from Polymarket's order-book history, quiet markets can have gaps that are left unfilled, and closed/resolved markets end at trading close. It also states that the output includes a chart in the card and clarifies the tool is informational, not advice.

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 the primary use case, followed by input forms, return values, and caveats in a logical order. Despite being one dense paragraph, every sentence contributes useful selection or invocation context 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?

Given that an output schema exists and annotations cover safety traits, the description is complete: it explains the use case, accepted inputs, default range/outcome behavior, returned metrics, data provenance, gap behavior, and closed-market edge cases. An agent has enough information to select and call the tool 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 description coverage is 100%, so the schema already documents market, outcome, and range thoroughly, including defaults and enum values. The description reinforces accepted market forms and time ranges, but adds little parameter-level detail beyond the schema; baseline 3 is appropriate.

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 resource and operation: it retrieves a prediction market's price/odds history over time, and it explains exactly what the return contains (start/end probability, change, high/low, chart). The examples and scope make it clearly distinguishable from siblings such as current-odds or market-flow tools.

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 an explicit triggering condition — 'Use this when the user asks how the odds ... have changed over time' — and illustrates it with several concrete query examples. It does not explicitly name when not to use it or point to alternative siblings for current odds versus historical odds, so it falls short of a full 5.

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