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

The readOnlyHint annotation already declares this as safe, and the description adds concrete behavioral details about the response fields and optional tag filtering. It does not disclose pagination or rate limits, but for a simple list operation this is acceptable.

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 two sentences, front-loaded with the core action and resource. Every word contributes meaning; no fluff.

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 list tool with one optional parameter and readOnlyHint annotation, the description adequately covers the response contents and filtering behavior. It lacks details on ordering or size limits, but these are not critical for this simple tool.

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 schema fully covers the 'tag' parameter with a clear description, achieving 100% coverage. The description merely restates that filtering by tag is optional, adding no semantic value beyond the schema.

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 begins with 'List all monitors on the account,' a specific verb+resource that clearly identifies the tool's function. It enumerates the return fields (up/down status, kind, target, interval, last check), distinguishing it from sibling tools like get_monitor which targets a single monitor.

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 states the tool lists all monitors and optionally filters by tag, providing clear context for when to use it. However, it does not explicitly reference alternatives or exclusions, such as 'for a single monitor use get_monitor.'

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