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

Goes well beyond the readOnly/idempotent/openWorld annotations by disclosing exactly what is NOT mutated (history, monitor state, status page, notifications), the evaluation semantics that mirror the worker (only 2xx is ok, redirect = failure, 10s timeout, 2xx without keyword text = failure), the failure payload shape (reason, message in PT-BR, location for redirects), and a hard rate limit of 10 tests/minute with the rate_limited error and wait time in the message.

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?

Front-loaded with the core behavior and consequences before the routing advice, and every sentence carries information. It is on the long side and re-explains keyword/2xx failure rules that the schema already states, which is the only mild redundancy.

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 stateless test tool with no output schema, the description still covers the return shape (reason/message, location on redirect) and the rate-limit error, so an agent knows what success and failure look like plus the downstream state implications.

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 coverage is 100%, so the baseline is 3; the description earns extra by clarifying precedence and semantics beyond the schema: passing `id` exercises the monitor's URL and keyword together, `url` is for ad-hoc public https addresses, and the keyword argument overrides the monitor's keyword only for this single test.

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 opening sentence states a precise verb+resource+scope: run an HTTP check once, now, return the result and persist nothing. It explicitly distinguishes itself from siblings by naming criar_monitor for ongoing monitoring and listar_checks for history, so an agent can route correctly without opening any schema.

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?

Gives concrete when-to-use triggers ('depois de um deploy ou de uma correção', 'antes de decidir monitorar') and explicit alternatives with the condition that selects them ('Pra começar a vigiar, use criar_monitor; pro histórico, listar_checks'). Also states the selection rule between the two entry parameters.

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