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

No annotations are provided, so the description bears the full burden of behavioral disclosure. It states it is a calendar and indicates it finds the cheapest week, but it does not disclose output format, data source, whether it requires both departure and arrival, or any limitations. This is insufficient for a tool with zero annotation support.

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 extremely concise—two short sentences that are front-loaded with the core value proposition. Every word earns its place, making it highly 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?

Despite having 6 parameters and no output schema or annotations, the description does not explain what the calendar output looks like, how weeks are displayed, or any required fields. It is too sparse to be fully usable without additional context or examples.

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 covers 100% of parameters with descriptions, including types and defaults, so the baseline is 3. The description itself adds no parameter-specific meaning, but the schema already documents each parameter sufficiently.

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 'Weekly price calendar for a route. Find the cheapest week to fly' clearly identifies the tool's purpose: providing a weekly price overview to help find the cheapest travel week. It names a specific resource (price calendar) and action (find), but it does not explicitly differentiate itself from sibling tools like 'cheapest_flights' or 'route_compare'.

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 comparing prices across weeks but provides no explicit guidance on when to use this tool versus alternatives, no prerequisites, and no exclusions. It offers enough context to infer a 'when to use' but lacks direct comparison with sibling tools.

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