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

Annotations only indicate non-read-only, open-world, non-idempotent behavior. The description adds valuable behavioral context: checks run from probes in several countries, downtime semantics, and the duplicate-risk warning. It does not mention response details, but the output schema likely covers those and no annotation contradiction exists.

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?

Four short, information-dense sentences, each earning its place. It tackles purpose, alternative selection, probe geography, and duplicate-avoidance without verbosity.

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?

Combined with a fully self-describing schema and output schema, the description gives a complete picture for a create tool: what it creates, when to use it, how to avoid duplicates, and the geographical context. It just misses a brief note on what the successful response contains, but that is largely available through the schema structure.

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?

Schema description coverage is 100%, so the baseline is 3. The tool-level description does not add parameter-specific semantics beyond what the schema already provides. The url field description itself adds the bare-hostname exclusion, but that is not part of the main tool description.

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 uses a specific verb and resource: 'Watch a web page or endpoint over HTTP/HTTPS' and defines what counts as downtime ('unexpected status code, a timeout or a connection failure'). It also clearly distinguishes itself from create_api_monitor, its closest sibling.

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 gives explicit usage boundaries: 'This is the right type for anything a browser would open' and directs to create_api_monitor when the response body matters. It also tells the agent to call list_monitors first to avoid duplicates, a clear when-to-use prerequisite.

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