ygo_get_monthly_meta

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

With no annotations, the description carries the full burden of disclosure, and it does substantial work: it names the upstream endpoint, states that the figures are live, and describes the freshness evidence returned. It does not say what happens for the unsupported formats (error vs. empty result), nor whether responses are cached or how forceRefresh interacts with that cache.

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 front-loaded 'USE THIS for...' directive is good structure, but the closing instruction is stated twice in near-identical form ('Do not quote a tier list from memory. Do not answer from memory; call this tool first.'), which is wasted space in an otherwise short description.

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 an optional-parameter read tool with no output schema and no annotations, the description is mostly sufficient: it explains provenance, coverage limits, and the shape of the returned data. Residual gaps are refresh/caching behavior and disambiguation from the daily and comparison meta siblings.

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%, so all four parameters are already documented and the baseline of 3 applies. The description adds only the format caveat (TCG/OCG live, others not); it does not clarify the tension in the schema where month claims to default to the current month but declares a fixed default of 11.

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 uses a specific verb and resource ('Live tier list straight from the YugiohMeta API (/api/v1/deck-types/rankings)') and enumerates what the result contains (share %, total tops, player counts, live staples, freshness evidence). The coverage boundary ('AE/Genesys/Master Duel have no live source') further sharpens what this tool is for. However, it does not distinguish itself from close siblings such as ygo_get_daily_meta or ygo_compare_monthly_meta, so an agent cannot tell which to use from this text alone.

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?

Usage is stated forcefully: use this for any 'what is the meta / tier list / share %' question, and do not answer from memory. A negative case is also given for formats with no live source. What is missing is explicit routing to the alternative tools when the user wants a month-over-month comparison or a daily snapshot.

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