Current price

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

Annotations already cover the safety profile (readOnly, idempotent, openWorld), so the bar is lower, and the description clears it by disclosing plan gating for graded values, free-plan availability, and a unit cost. That is real non-obvious context an agent needs before calling. It stops short of describing freshness/latency or what happens when a card has no price.

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?

Three short sentences, front-loaded with what the tool returns. Each sentence carries information, though 'Available on the free plan' and 'Cost: 1 unit' are adjacent gating facts that could be tightened into one clause.

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?

There is no output schema, so the description properly names the return components (price, market, confidence rating), and it covers the free/Pro split that governs which inputs are legal. Coverage is solid for a 3-param read tool; it lacks only edge-case behavior (no price found, currency conversion semantics).

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 grade, card_id, and currency, including the RAW default and the Pro requirement. The description's 'Raw (ungraded) by default' restates schema content rather than adding new meaning. Baseline 3 is correct when the schema does the heavy lifting.

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+resource ('Current price for a card') and names what comes back (market of origin, confidence rating). It is distinguishable in spirit from siblings like flipzi_get_sold_comps and flipzi_get_history, but it never names an alternative, so it lands just short of 5.

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 by the resource name. The description instead spends its words on plan gating ('graded values need the Pro plan', 'Available on the free plan') and cost, which help selection but are not when-to-use-vs-alternative guidance. No sibling or exclusion is mentioned.

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