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

Annotations already declare readOnlyHint, destructiveHint, idempotentHint, and openWorldHint, covering the most critical behavioral aspects. The description adds no additional behavioral context (e.g., rate limits, authentication, error handling). While adequate with annotations, it misses an opportunity to disclose nuances like potential 404 errors for nonexistent users.

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 description is concise (single sentence) and front-loaded with the core action ('Get a Lichess user's profile'). It efficiently lists key output fields without unnecessary verbosity. Minor improvement could be separating output details for readability.

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?

Given the presence of an output schema, the description does not need to detail return format. It covers the main purpose and enumerates major data categories (ratings, games, bio, etc.). For a simple read operation with no complex side effects, this is sufficiently complete.

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 input schema (100% coverage) fully describes the 'username' parameter, including constraints and an example. The description does not add any new semantic information about the parameter; it only expands on the output. Thus, it meets the baseline but provides no extra value.

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 clearly states the tool's function as retrieving a Lichess user's profile and enumerates the included data fields (ratings, games, online status, etc.). However, it does not differentiate from sibling Lichess tools like 'lichess.players.top' or 'lichess.puzzle.daily', leaving some ambiguity about when to use this versus those alternatives.

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?

No guidance is provided on when to use this tool versus other Lichess tools or alternatives. The description lacks any context about prerequisites, typical use cases, or conditions that would help an agent decide between this and sibling tools.

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