e

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

No annotations are provided, so the description carries full behavioral disclosure burden. It states this is a 'Get' operation (implying read-only) and specifies the exact value returned (e ≈ 2.71828). However, it doesn't mention precision, format, or any computational characteristics. For a zero-parameter tool with no annotations, this is adequate but minimal behavioral context.

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 yet complete: one sentence stating the tool's purpose and return value, followed by parenthetical domain/category tags. Every element earns its place—no wasted words, perfectly front-loaded with the core functionality. This is model efficiency for a simple tool.

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?

For a zero-parameter tool with no output schema and no annotations, the description provides sufficient context: it states what constant is returned and its approximate value. However, it doesn't specify the return format (e.g., numeric precision, data type) or any error conditions. Given the tool's simplicity, this is reasonably complete but could slightly enhance clarity about output characteristics.

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 parameters with 100% coverage (empty object). The description appropriately doesn't discuss parameters since none exist. It focuses instead on what the tool returns. With zero parameters, the baseline is 4, and the description correctly avoids unnecessary parameter discussion.

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 explicitly states the tool's purpose: 'Get Euler's number e ≈ 2.71828.' It specifies the exact mathematical constant returned, distinguishes it from siblings by focusing on this specific fundamental constant, and provides domain/category context. This is a clear, specific verb+resource statement with no ambiguity.

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 context through the domain/category tags ('Domain: arithmetic, Category: general'), suggesting this is a general-purpose mathematical constant tool. However, it doesn't explicitly state when to use this versus alternatives (like compute_e_limit or compute_e_series from the sibling list), nor does it provide exclusion criteria. The guidance is clear but lacks sibling differentiation.

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