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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, not open world), and the description adds substantial unannotated behavior: the tie-breaking chain (bosses killed, then earliest latest kill, then name), what counts as a kill (2 matching installs, timed at earliest report, or an officer board post which carries no time), how the boss list is derived, and explicit reporting of missing data. This is far beyond what the annotations convey.

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?

Front-loaded with the ranking rule, then the kill definition, then the excluded interpretations, then routing to alternatives — a sensible order. It is dense but nearly every sentence carries a rule; the parenthetical qualification about officer-published kills having no time is slightly heavy for the space it takes.

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 read-only ranked listing with a full input schema, output schema, and complete annotations, the description supplies the ranking logic, kill derivation, tie handling and data source. Nothing needed to call it correctly or interpret the ordering 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?

Schema description coverage is 100%, including the exact semantics of instanceMapId (map id from a search_knowledge hit of kind instance, omit for newest raid with a kill), realm and faction scoping, and limit bounds. The description adds only indirect meaning, explaining that the boss list is scoped to the given instance, but does not clarify parameters beyond the schema, so the baseline 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?

States a specific verb (ranks) and resource (every guild with an agreed kill in one instance) plus the exact ordering criteria. It immediately separates itself from siblings by naming guild_board and guild_search as different tools, so an agent can pick this one without reading the other 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?

Explicitly says 'Use it to compare guilds' progress in one raid or dungeon' and then routes the agent elsewhere: guild_board for one guild's own board, guild_search to find a guild. It also rules out a plausible wrong expectation ('no score, no rating and no total across instances'), which is a when-not-to-use signal.

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