compare_cards

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

With no annotations provided, the description carries the full disclosure burden. It explains the output is a field-by-field comparison with 'machine-readable differences,' which is behaviorally informative. However, it doesn't disclose the exact fields compared, what 'machine-readable differences' means in practice, or any limits/edge cases beyond the 10-card cap. The output schema exists but the description doesn't elaborate on behavioral traits like error handling or partial comparisons.

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?

A single, functional sentence with the core purpose and a limit ('up to 10 cards'). It's efficient with no fluff. Front-loading is good — the verb 'Return' is first. It could arguably add a sentence on usage, but as written it is compact and queued on value.

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 is moderately complex (3 params, comparison logic, toggles) but the output schema exists and provides return structure expectations. The description covers the essential purpose and scale limit but stays thin on behavioral nuance like what happens with identical cards, missing fields, or invalid IDs. Given the output schema provides return-type clarity, a score of 3 is reasonable — adequate but not rich.

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 0%, so the description must compensate, but it adds nothing about the individual parameters. card_ids is self-explanatory from the schema, and include_rules/include_prices defaults are visible in the schema. However, the description does not explain what 'rules' and 'prices' specifically refer to in the comparison context, nor note that these booleans toggle comparison sections. With 3 parameters and 0% coverage, the description falls short of compensating but the schema itself is reasonably clear.

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 a clear verb+resource: 'Return a field-by-field comparison and machine-readable differences for up to 10 cards.' It clearly identifies the resource (cards) and the operation (comparison). It distinguishes itself from sibling tools like compare_card_prices and compare_printings which target specific aspects, whereas this one is a general field-by-field comparison.

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?

The description implies a use case (comparing multiple cards) but provides no explicit when-to-use vs alternatives guidance. It does not clarify when one should use this over compare_card_prices (price comparison), compare_printings (printing variants), or get_card (individual card details). The 'up to 10 cards' constraint offers some boundary context but no exclusions or alternative tool references.

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