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

Annotations already cover readOnlyHint=false and idempotentHint=false. The description adds useful behavioral context beyond annotations: consumes check quota, stores a receipt, and may deliver a configured webhook. It also reiterates the non-idempotent nature. No contradiction with annotations.

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, zero waste. The main purpose is front-loaded, side effects follow, and the clarifying 'not an idempotent read' is a useful closing distinction. Every sentence earns its place.

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 2-parameter tool with no output schema, the description covers the action, side effects, and a hint about the receipt content. It doesn't detail the receipt format or error cases, but for a trigger-like tool this is adequate. A little more detail on the receipt would push it to 5.

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% – both api_key and monitor_id have adequate descriptions. The tool description adds no parameter-specific meaning beyond the schema, so baseline 3 is appropriate. It mentions the output receipt but not 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 ('Run a monitor now') and resource ('monitor'), and clarifies the output ('source- and hash-bound change receipt'). It explicitly disambiguates from a read by saying 'Not an idempotent read', which distinguishes it from sibling list_changes. This is clear and specific.

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 implies when to use it (to trigger an immediate check) and warns about quota consumption, which helps decide. However, it does not explicitly name alternatives or state when not to use it (e.g., 'if you only need past changes, use list_changes'). The exclusion is implicit via 'not an idempotent read', but not fully explicit.

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