is_fibonacci_number

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It states the tool checks Fibonacci membership but doesn't describe what happens with invalid inputs (e.g., negative numbers), performance characteristics, error handling, or the return format (e.g., boolean, string). For a tool with no annotation coverage, this leaves significant gaps in understanding its behavior.

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 and front-loaded: a single sentence that directly states the tool's purpose, followed by domain/category context. Every word earns its place with zero redundancy or fluff, making it easy to parse quickly.

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 (one parameter, no output schema, no annotations), the description is incomplete. It lacks details on return values (e.g., boolean result), error conditions, and usage context. While minimalism can be appropriate, for a tool with no structured metadata, the description should provide more operational context to be fully helpful.

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 has 0% description coverage, documenting only that 'n' is an integer. The description adds no parameter-specific information beyond implying 'n' is the number to check. It doesn't clarify valid ranges (e.g., non-negative?), units, or examples. With low schema coverage, the description compensates minimally, meeting the baseline for adequate but incomplete parameter semantics.

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 purpose: 'Check if a number is a Fibonacci number.' It specifies the verb ('Check') and resource ('a number'), and the domain/category context helps clarify it's about mathematical sequences. However, it doesn't explicitly differentiate from sibling tools like 'fibonacci' or 'fibonacci_sequence', which might generate or list Fibonacci numbers rather than test membership.

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 no guidance on when to use this tool versus alternatives. While the domain/category hints at mathematical contexts, there's no mention of when to choose this over sibling tools like 'fibonacci' (which might generate Fibonacci numbers) or 'is_triangular_number' (a similar membership test for different sequences). No prerequisites, limitations, or typical use cases are specified.

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