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

With no annotations provided, the description carries the full behavioral burden and does so well: it discloses frozen inputs since 2026-09-07, that responses carry usd_panel {frozen: true, as_of}, the required terminology ('Say "last published", never "today"'), and the guarantees of being deterministic, distribution-free, and never-under-protective. These are substantive operational facts an agent could not infer from the schema 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?

The critical frozen-input caveat is correctly front-loaded, and each sentence adds information. It is somewhat verbose, with mild promotional framing ('honest', 'recommended') and a parenthetical VaR explanation that could be tightened, but there is no true 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?

An output schema exists, so return-value exposition is not required, yet the description still notes the usd_panel envelope and letter grades to set expectations. Combined with the frozen-input warning, sibling contrast, and honesty guarantees, nothing an agent needs to invoke this correctly is missing.

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% for the single card_name parameter, so the schema already fully documents the input. The description adds no syntax, format, or resolution guidance beyond what the schema provides, making the baseline 3 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?

States a specific verb and resource ('Get the calibrated conformal risk forecast for a trading card') and immediately differentiates itself from the sibling simulate_price by contrasting its distribution-free calibration with Monte Carlo simulation. An agent can distinguish this from get_price, simulate_price, and get_market_snapshot without opening a schema.

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 declares itself 'the recommended, honest default forecast,' which is a clear usage signal, and implicitly routes agents away from simulate_price for distribution-free needs. It does not, however, give explicit when-not-to-use conditions or name the alternative tool directly, so it stops short of full routing guidance.

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