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

Beyond the annotations, the description adds useful behavioral context: the created subscription is not active, and activation requires payment and operator approval. It does not contradict the annotations' readOnlyHint=false, idempotentHint=true, or destructiveHint=false.

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 with no filler. The most important fact—stopped state—appears early, and the activation prerequisite is stated succinctly.

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 tool with a nested policy object, four parameters, no output schema, and no parameter-level guidance, this description is too thin. It communicates the lifecycle state well but leaves policy semantics, return value, and behavior on repeated registration completely unexplained. The schema and annotations alone do not make the tool safely invokable.

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 0%, so the description needed to compensate for parameter meaning. It identifies 'Base Sepolia' and 'validated policy,' but offers no substantive explanation of the walletAddress, label, or the policy's many nested fields. The parameter names in the schema still do most of the semantic work.

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 clearly specifies the action ('Registers'), the resource (a Base Sepolia monitor subscription), and the resulting state ('stopped state'). It also distinguishes itself from sibling tools like stop_monitor_subscription by making clear that this is the initial registration, not an activation or state change.

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 clear context: this tool only registers in stopped state, and payment plus operator approval are still needed before activation. It does not explicitly name alternatives or edge cases, so it stops short of a full 5, but the usage context is unambiguous.

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