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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, and the description reinforces this by stating 'This tool is read-only.' It adds value beyond the annotations by revealing that the tool 'reports live versus held primitives explicitly,' which is useful behavioral context about what the returned capability inventory will contain.

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 a single informative sentence followed by a short clarifying sentence. It is compact and front-loads the tool's core purpose before listing capability categories, though the long enumeration makes it slightly dense.

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 parameterless, read-only capability-discovery tool, the description covers the essential behavior and the kind of information returned. There is no output schema, but the description's mention of 'live versus held primitives' gives the agent a clear expectation, and no critical input or side-effect information is missing.

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 zero parameters and schema description coverage is effectively 100%, so there are no parameter semantics for the description to clarify. With no parameters, the baseline is 4, and the description appropriately focuses on the tool's subject matter rather than input handling.

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 states a specific verb and resource: 'Describe Evercraft Web capabilities for AI agents.' It then enumerates the concrete capability areas (URL fetch/extraction, web search, browser automation, etc.), which makes the tool's purpose unmistakable and naturally distinguishes it from the sibling tools fetch_url and route_web_request.

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 this tool is for discovering what Evercraft Web can do, but it does not explicitly say when to use it instead of fetch_url or route_web_request. There are no stated exclusions or alternative-selection conditions, so the agent must infer the usage from the tool's purpose.

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