card_forecast

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

With no annotations, the description carries the transparency burden. It discloses the free/paid nature, 'FREE — no payment required', and mentions the paid alternative. It also explains edge cases like card_name resolution ('resolved to the best match') and momentum grade returning 'NA' on a drift spike. However, it does not cover error behaviors or rate limits.

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 organized with a leading summary, a bulleted return list, usage guidance, and a tip. It is slightly verbose with repeated 'FREE' emphasis and a detailed field list, but the structure makes it easy to scan.

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?

The tool has no output schema and only two flat parameters, so the description covers the key context: purpose, inputs, return fields, usage conditions, and relationship to siblings. It lacks specifics on API path (except the tip) and error handling, but these are not critical for selection.

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 has no property descriptions (0% coverage), so the description must explain parameters. It does: 'Pass a card_name (resolved to the best match) or a TCGplayer product_id.' It clarifies the either/or relationship but does not discuss what happens if both are omitted, despite the schema defaults indicating optionality.

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 the exact purpose: 'The FREE 30-day read on ONE card: point forecast, bands, VaR, and the Safe-Hold / Momentum letter grades, in one call.' It also differentiates from siblings like simulate_price by noting escalation for other horizons.

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?

Explicit guidance is provided: 'Use this FIRST for "is this card a safe hold?", "30-day outlook?", "how risky is X?".' It also names the alternative: 'For other horizons, the full percentile curve, or Monte Carlo paths, escalate to simulate_price (paid).'

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