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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context: the exact rules checked, the input format (one card per line, examples, side deck marker), and the fact that it also prices the deck. It does not describe the output structure, but given the annotations, this is a moderate addition.

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 a single, well-structured sentence that front-loads the purpose and then provides concrete input examples. Every word adds value—there is no fluff or repetition, and it is appropriately sized for the tool's complexity.

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 description explains the input and the rules checked, but it does not describe the return value. Since there is no output schema, the agent is left guessing what the tool returns (e.g., a validation report, a price, a boolean). This is a notable gap for a tool that checks multiple rules and computes a price; the description should at least hint at the response structure.

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 50%: source has a description, but decklist has none. The description compensates by detailing the decklist format ('One card per line, e.g. ...' and 'a Side Deck line starts the sideboard'), which adds meaning beyond the schema. It also confirms the source semantics by referencing the user's Deckodex preference, already in the schema, so the added value is primarily for decklist.

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 clearly states the tool's purpose: 'Check a decklist against the deck rules... and price it.' It enumerates specific rules (50-card main deck, max 4 copies, max 2 colors, banlist, sideboard) and distinctively positions it as a validation-and-pricing tool, clearly different from siblings like save_deck or price_list.

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 gives clear context on what the tool does and the input format, implying it should be used when a user wants to validate and price a decklist. However, it does not explicitly state when not to use it or mention alternatives (e.g., 'use save_deck after validation' or 'use price_list for single cards'), so it lacks explicit exclusion guidance.

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