Authenticate a player (client API)

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

Annotations indicate readOnlyHint=false and openWorldHint=true. The description adds the key behavioral detail that 'the session token is held in memory for subsequent calls.' No contradictions. It could mention account creation side effect, but that's covered by schema.

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 three sentences, front-loading the purpose and prerequisite. Every sentence contributes value without redundancy. Extremely efficient.

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 6 parameters and no output schema, the description covers the core workflow but omits return value details and error conditions. It adequately explains the prerequisite and token handling, but more context on expected outputs would improve completeness.

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 parameters are well-documented. The description only summarizes 'Supports device, custom, or email auth' and mentions token behavior, adding no additional meaning beyond the schema. Baseline 3 is appropriate.

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 'Establish a player session for the client API (:7350)', which is a specific verb+resource combination. The tool's purpose is clearly differentiated from sibling tools that handle admin actions (ban, get, etc.) or other operations.

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?

The description explicitly says 'Required before calling other client/player endpoints', providing clear when-to-use guidance. It mentions supported auth methods but does not give exclusions or alternatives. Siblings don't overlap, so ambiguity is low.

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