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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower. The description adds real value beyond them: the required auth scope 'decks:read' and the fact that the payload spans commanders, sideboard and notes, telling the agent this is a full-fidelity single-deck read. It does not mention truncation or pagination for large decks.

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?

Two sentences, no filler, with the returned content front-loaded and the permission requirement last. Nothing could be removed without losing information.

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?

For a single-parameter read-only tool with no output schema, the description supplies the important return-shape summary (cards, commanders, sideboard, notes) plus the auth requirement. That is enough for an agent to call it correctly and anticipate the response.

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 coverage is 100% and the single deck_id parameter is already documented with format uuid and provenance ('from list_my_decks'). The description adds no further meaning about the identifier, so this is the baseline case where the schema does all the work.

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 names the resource (one of the user's decks) and enumerates the returned content: cards, commanders, sideboard, notes. It implies retrieval rather than a mutation, and the singular 'one of the user's decks' implicitly contrasts with the plural list tool. It stops short of naming a sibling or using an explicit verb, so it is clear but not maximally distinguishing.

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 prerequisite 'Needs decks:read' is a genuine usage condition, and the schema says the id comes 'from list_my_decks', which hints at the list→get workflow. However, there is no explicit when-to-use versus analyze_my_deck or analyze_my_deck-style siblings; guidance is implied rather than stated.

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