meta_snapshot

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds useful behavioral context about what the payload contains (legality under today's list, average points for Genesys, common blockers), but says nothing about data freshness/lag, rate limits, or error behavior.

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, front-loaded with the resource and its scope, with the format clarification placed last. The long field enumeration is dense but each item maps to real payload content, so little is wasted.

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 does the right work by enumerating the returned aggregates, which is enough for an agent to know what it gets back. Gaps remain around the meaning of 'top'/'days' and any freshness or pagination caveats.

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 carry the load. It fully disambiguates the required 'format' enum (Genesys = Genesys events; Advanced = TCG lists outside Genesys and OCG), but 'top' (default 15) and 'days' (default 60) are never explained — only implicitly hinted at by 'Recent tournament tops'.

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 concrete resource and enumerates its scope precisely: recent tournament tops, deck-type shares, top-8s/wins, legality counts, most_common_blockers, and most-played cards. An agent can tell this is a meta-aggregate snapshot rather than a card- or deck-level tool. However, it never explicitly contrasts itself with the closest sibling (meta_inclusion), so it stops short of a 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?

There is no statement of when to reach for this tool versus meta_inclusion, archetype, or search_cards — usage is only inferable from the returned-field list. The only routing-style help given is defining the format enum values, which is parameter semantics rather than usage guidance.

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