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

Annotations already carry readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds value beyond annotations by disclosing the composition of the returned data — meta share, results, most-played cards with average copies, and decklists — which warns the agent about the scope of the payload. Minor gaps: 'latest' and 'results' are not precisely bounded, but with rich annotations the bar is lower.

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 sentence of about 30 words carries the full purpose, scoping condition, output contents, and an alternative-tool pointer. The primary function is front-loaded ('One archetype in a format') and the sibling reference is placed at the end. Every clause earns its place with no filler.

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?

With no output schema, the description carries the return-contract burden, and it discharges it well by enumerating the four data groups an agent can expect. Parameters are fully covered by the schema and safety by annotations. The only real gap is ambiguity about how many 'latest top tournament decklists' are returned and what 'results' encompasses, which is minor for a read-only informational tool.

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%, with both 'format' and 'archetype' clearly documented in the input schema, including the format-code default behavior and the archetype reference back to get_meta. The description adds no parameter-level detail beyond what the schema already provides, so the baseline of 3 applies.

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 a specific resource ('One archetype in a format') and enumerates exactly what is returned: meta share, results, most-played cards with average copies, and latest top tournament decklists. It also distinguishes itself from get_meta_deck by pointing out the scope difference, so an agent can tell it apart from siblings without inspecting schemas.

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 explicit routing guidance for the closest sibling ('use get_meta_deck for a full list'), and the framing 'One archetype in a format' implies the selection condition: use this when you want a single archetype's detailed breakdown. It lacks a full when/when-not matrix across all siblings, but the key alternative is named with a condition, which is more than most tools provide.

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