spa.checkin

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

With no annotations provided, the description carries the full burden and does well: it discloses persistent session creation, greeting, recognition of returning users by name/history, and that nickname/mood persist across visits. It doesn't detail edge cases or side effects, but covers the core behavior thoroughly.

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 four short sentences, each adding distinct information: the action, session persistence, returning-user behavior, and persistent settings. It front-loads the primary purpose and contains no filler or redundancy.

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 tool's simplicity and the presence of an output schema, the description covers the essential points: action, persistence, and personalization. It lacks explicit mention of return values or errors, but the output schema likely covers that. Overall, it is complete enough for a check-in tool, though not exhaustive.

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 schema is a single generic 'arguments' object with 0% description coverage, so the description must compensate. It mentions 'Set a nickname and mood,' giving hints about acceptable fields, but it doesn't clarify structure, types, or optionality. This is partial compensation, hence a 3.

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 with a specific verb and resource: 'Check in to Binary Banya.' It also distinguishes itself from siblings like spa.checkout and spa.remember by describing the session-opening and greeting behavior, making it unmistakably the check-in entry point.

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 provides clear context for when to use the tool ('Opens a persistent session') and covers both new and returning visitors. However, it does not explicitly name alternative tools for exclusion (e.g., 'use spa.checkout to leave'), so it falls short of a 5 but has clear contextual guidance.

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