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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), so the description is free to add operational detail — and it does: a hard cap of 180 points, chronological ordering (oldest first), per-outcome ordering matched to outcome order, and a 0–1 price range. The note that closed and settled markets are covered is exactly the kind of behavioral fact an agent cannot infer from annotations alone.

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, both dense with information and zero filler. The return shape is front-loaded ahead of the eligibility note, so the most important fact arrives first.

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?

With no output schema, the description carries the burden of describing the return value and largely succeeds: count cap, ordering, per-outcome layout, and value range are all covered. Minor gaps remain — timestamp format and behavior when a market has no price history are unstated — but nothing blocks a correct call.

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?

There is a single parameter and the schema documents it at 100% coverage, including that the UUID should come from list_markets or get_market. The description adds only the implicit notion that the id selects 'a market', so it neither needs to nor does compensate further. 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?

The description names the specific resource and verb ('How a market's prices moved') and immediately pins down the shape of the payload: up to 180 timestamped points, oldest first, one price per outcome in outcome order. This is clearly distinguishable from metadata siblings like get_market or list_markets, which describe markets rather than their price trajectory.

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?

Usage is implied rather than stated: the agent learns this is the tool for viewing how a market's view of an outcome evolved, and that it works 'including for closed and settled markets' — a useful eligibility note. However, there is no explicit guidance on when to prefer this over get_market, no mention of prerequisites, and no stated exclusions.

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