Lichess player profile and ratings

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and non-destructive, so the safety profile is fully covered by structured data. The description's addition is mostly return-content scope (which speed ratings, provisional flags, W/L/D totals), and since an output schema exists that content is largely redundant. It does not mention auth or rate limits.

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?

One front-loaded sentence with zero filler: verb and resource come first, and the parenthetical field list earns its place by defining scope rather than padding. Nothing to cut without losing information.

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 single-parameter read-only lookup with a full output schema and complete annotations, the definition is essentially complete. The only minor gap is that most of its text describes return values that the output schema already documents, and no auth/rate-limit context is offered.

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?

The single parameter has 100% schema description coverage, including a pattern and a concrete example ('thibault') and the case-insensitivity note, so the schema carries the full burden. The description adds nothing about the username argument beyond implying profile lookup, which is the baseline-3 case for fully documented params.

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?

Specific verb ('look up') plus specific resource ('Lichess player'), and it enumerates the exact data scope (per-speed ratings, game counts, provisional flags, W/L/D totals, profile info). That scope makes it clearly distinguishable from siblings like get_game, recent_games, and opening_stats, which operate on games/openings rather than a player profile.

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 implied by the verb and resource — an agent can infer this is the profile-lookup tool — but there is no explicit when-to-use statement and no reference to alternatives such as recent_games when the agent actually wants game history. No exclusions or prerequisites are stated anywhere.

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