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

Annotations declare non-destructive, idempotent writes, and the description adds substantial context beyond them: the unverified-account capability ceiling (manual runs capped at 3/day), the dedup rule that matches the idempotentHint, and pointers to setup.manualRuns / setup.nextStep / setup.afterProof in the response. This tells an agent exactly what state it will leave the account in.

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-loads the action and the return shape in the first sentence, then layers prerequisites and dedup behavior. The dense parenthetical-and-semicolon style packs a lot of value per sentence, though it reads as one heavy block rather than clearly separated points.

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?

There is no output schema, yet the description names three specific response fields (setup.manualRuns, setup.nextStep, setup.afterProof) so an agent knows what it gets back. Combined with the dedup rule, verification paths, and a docs link, nothing essential for correct invocation 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?

Schema description coverage is 100%, so url, name and platform are already documented, and the description adds only indirect reinforcement by explaining why platform matters (WordPress plugin vs. domain-only verification). Baseline 3 is appropriate since the schema carries parameter meaning.

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?

Opens with a specific verb+resource ("Start monitoring a website") and immediately clarifies that it returns the site plus its setup state. It also implicitly separates itself from siblings by naming trigger_scan as the tool that consumes the pre-verification state and by describing the domain-verification path that verify_site relates to.

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 clear situational context: what works before ownership is proven (3 manual public-monitor runs/day via trigger_scan), what requires proof, and what happens if the same domain already exists (returns existing site instead of a duplicate). It stops short of explicitly stating when not to use this versus start_monitoring_for_goals, but the operating conditions are concrete.

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