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

With readOnlyHint and destructiveHint already covering the safety profile, the description adds useful behavioral detail: it specifies that only active keys are listed, lists the returned metadata fields, and states the authentication requirement. It does not, however, describe pagination or ordering behavior, so it stops short of exhaustive transparency.

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?

Three sentences are front-loaded with purpose, then return fields, then auth requirement. Every sentence earns its place and there is no redundant or vague filler.

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 simple read-only list operation with no parameters and no output schema, the description covers purpose, return values, filtering to active keys, and authentication. Nothing an agent needs in order to call it correctly 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 tool takes zero parameters, so there are no parameter semantics to clarify. The baseline for a zero-parameter tool is 4, and the description does not need to and does not introduce parameter details.

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: 'List all active API keys for the authenticated operator.' It scopes the operation to active keys and the authenticated operator, which distinguishes it from sibling tools like provision_api_key and revoke_api_key without needing to name them.

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?

Usage is implied by the tool name and the description's scope, but no explicit when-to-use guidance or alternatives are named. The only usage-adjacent detail is the authentication requirement, which is a prerequisite rather than a decision rule.

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