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

Beyond the readOnlyHint/openWorldHint annotations, it discloses the authentication requirement (agent key) and the graceful failure behavior ('Without one, says how to get it'), which is exactly what an agent needs to handle an auth error. It also reveals that the response carries plan metadata (wallets allowed/used, expiry), adding real context the annotations do not cover.

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?

A single dense sentence with no filler, and the core content (what you get back) is front-loaded before the auth note. The nested clauses make it slightly run-on, but every clause carries information.

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?

With no output schema and no input parameters, the description carries the burden of explaining return content, and it does so by enumerating labels, chains, last-checked times, and plan usage. Authentication and failure modes are also covered, leaving no practical gap for an agent calling this tool.

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?

The tool takes zero parameters, so there is no parameter meaning to convey; the baseline for a parameterless tool applies. The description wastes no space describing inputs and correctly focuses on outputs and preconditions instead.

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 names the specific resource (the user's watched wallets) and itemizes the content returned: private labels, chains, last-checked timestamps, plus plan limits. It is distinguishable from watched_events by focusing on wallet records rather than events, though the retrieval verb itself is only implied.

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?

Usage is implied by the title's '(paid)' marker and the 'Needs your agent key' prerequisite, which tells an agent when the call will succeed. No alternative tool is named and no when-not-to-use condition is stated, so an agent must infer that watched_events is the place to go for event data.

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