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

Annotations already declare readOnly, idempotent, non-destructive behaviour, so the bar is lower, yet the description still adds useful context: the exact data provenance (Kalshi, Polymarket, ICE futures, compute-index benchmarks, cheap-gpus.com median) and the unit of the returned price. It does not disclose the forecast horizon, latency, or what happens when a market has no contract for the requested family.

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, front-loaded with the core purpose and followed by provenance and coverage. Dense but every clause carries information; minor redundancy between 'market-implied' and the list of markets.

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?

An output schema exists, so return values need no explanation, and the description covers sources, units, and accepted inputs. However, for a tool whose central concept is a forecast, the absence of any horizon (what future period, whether daily/monthly granularity) is a substantive gap an agent needs to interpret the result.

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 0% with a single bare 'gpu' string and no enum, so the description carries the full burden; it does this well by enumerating the five accepted families (H100, H200, B200, A100, RTX 5090), which effectively supplies the missing enum. It falls short of stating whether input is case-sensitive or whether other families are rejected.

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?

States a specific verb-form resource ('market-implied future rental price for one GPU family') with explicit units and named data sources, and the word 'future' cleanly separates it from the sibling gpu_price_history and from current-price tools like cheapest_gpu.

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 only implied: an agent can infer this is the tool for forward-looking pricing, but the description never states when to prefer it over gpu_price_history or cheapest_gpu, nor any prerequisite or exclusion. No explicit alternative is named.

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