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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false. The description adds useful behavioral context beyond annotations: it states what the tool returns, that it returns registered:false when no webhook exists, and that prior wallet verification is required this session. 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?

The description is a single dense, well-structured sentence. It front-loads the [READ] marker and core resource, then packs the field list, absence behavior, and prerequisite without any filler.

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 parameterless tool with no output schema, the description fully covers what the agent needs to know: what is read, which fields are returned, what happens when no webhook is registered, and the session requirement. Nothing critical is missing for correct invocation.

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 has zero parameters, so there are no parameter meanings for the description to clarify. The description still adds value by listing the exact fields returned, giving the agent a clear picture of the tool's behavior despite the empty input schema.

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 begins with [READ] and states the exact action: reading the wallet's registered inbox webhook. It enumerates the returned fields (url, verified state, hmac_secret, failure count, timestamps), making the tool's purpose precise and easily distinguishable from register/delete webhook siblings.

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 clearly scopes the tool to reading the current wallet's webhook and gives the prerequisite 'Requires agent_verify_wallet this session,' which tells the agent when it is callable. It does not explicitly name alternative tools such as register_webhook or delete_webhook, but the read-only framing and registered-webhook scope make the selection context unambiguous.

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