Month summary

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 genuine value by enumerating the derived metrics returned (rating change per time control, how wins/losses ended, best win, worst loss), which functions as an output contract in the absence of an output schema. No auth or rate-limit notes, but none are critical here.

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 deliverable, then the default, then the usage cue; no filler sentences. The long enumeration of returned fields is dense but earns its place because no output schema exists.

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 correctly compensates by listing what comes back, and it covers defaulting behavior for year/month. It leaves one gap: username is listed as optional by the schema, yet the description never explains what happens if it is omitted.

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%, so year, month, rated_only, time_class and username are all documented in the schema itself. The description only echoes the current-month default, adding nothing beyond what the schema already states. 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?

The description states a concrete deliverable — a per-calendar-month performance summary — and enumerates its contents (record, rating change per time control, accuracy, streaks, openings). It is clearly differentiated from get_profile and get_ratings by the monthly aggregation, though it never names a sibling to contrast against.

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?

"Use this for questions like 'how did I do this month?'" gives an explicit trigger context, and "Defaults to the current month" clarifies the defaulting behavior. It stops short of stating when to prefer recent_games or get_ratings instead, so no exclusion guidance is present.

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