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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so safety is covered. The description adds genuine behavioral context beyond annotations: it is 'built from recent tournament results' and it 'Defaults to the latest format', which discloses the default-value behavior an agent needs to know. No contradiction with annotations.

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 with zero waste. The core purpose and output fields are front-loaded in the first sentence, and the default behavior is in the second. Every word earns its place.

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?

Complete for a simple read-only list tool: one optional parameter, rich annotations covering safety/idempotency, and the description enumerates the return contents (archetype, tier, meta share, deck count, top-8 count) so no output schema is needed. Nothing an agent needs to call it correctly is missing.

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?

With 100% schema description coverage, baseline is 3. The single 'format' parameter is well documented in the schema ('Format code like GD05; omit for the latest'). The description's 'Defaults to the latest format' largely echoes the schema, adding only marginal value. It does not add format-code syntax details beyond the schema.

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 specific verb+resource: 'The tournament meta for a format', enumerates exact output fields (tier, meta share, deck count, top-8 count) and the data source (recent tournament results). This clearly distinguishes it from siblings like get_archetype (a single archetype), get_meta_deck (a specific deck), and get_card (a card lookup).

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 usage context — it is the overall meta snapshot — but never explicitly names alternatives or says 'use this for the whole meta, not a single archetype/deck'. The sibling distinction is inferable from the sibling names (get_archetype, get_meta_deck) but no explicit when-to-use or when-not-to guidance is given.

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