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

With no annotations, the description carries the full burden. It discloses the read-only nature ('Get free time slots'), that it considers existing reservations, and that no API key is required. It does not detail rate limits or pagination, but the provided traits are sufficient for a simple lookup tool.

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?

Two sentences, no fluff. The first sentence immediately states the core purpose, and the second adds a qualification and a bonus fact. Every word earns its place.

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 (3 parameters, no output schema), the description covers the key aspects: what it returns, how to use resource_id, and that no auth is needed. It lacks explicit output format details, but for an availability check, the purpose is clear enough.

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 coverage is 100%, so the schema already documents each parameter's meaning. The description adds minimal extra parameter context (e.g., 'Resource UUID (from list_resources)') but mostly repeats what is in 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 clearly states the purpose: 'Get free time slots for a resource on a given date.' It uses a specific verb ('Get') and resource ('free time slots'), and distinguishes from siblings like create_reservation and cancel_reservation. The mention of 'No API key required' adds useful context.

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 implies usage for checking availability before creating a reservation, but does not explicitly state when to use vs. alternatives, nor does it exclude any cases. The context is clear enough, but lacks explicit guidance like 'Use this before create_reservation'.

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