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

With no annotations present, the description carries the full burden and does so: it discloses the required credential type (a2l_live_* LIVE token), the exact failure mode for the wrong token (registration_token_insufficient) with a recovery path, and the ADR-backed ownership model for the wallet principal. This is far beyond what a bare name/schema conveys.

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 piece is well front-loaded with a bolded 'When to use' lead and clear named sections for tokens and units. It is slightly long and leans on internal jargon (ADR 0010, /agents/me/home shape) that adds context but costs density.

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, so the description correctly supplies the return surface itself: which fields come back (balance, withdrawable, currency) and, critically, the micro-unit convention for balance_micro and withdrawable_micro. Combined with the auth guidance, an agent has everything needed to call and interpret the 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 the baseline is 4 and there is nothing for the description to compensate for. It does add useful meaning about return-value units (micro-units, 1 USD = 1,000,000), though that is more return-value than parameter semantics.

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+resource ('wallet snapshot' returning 'balance, withdrawable, currency') and explicitly distinguishes itself from the sibling `home` tool, noting both carry the same balances. An agent can route between the two without opening either schema.

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?

It gives an explicit when-to-use ('when you don't need the full home dashboard') and a when-not / alternative rule ('reg-token agents should use the `home` tool instead'), including the triggering error code. Nothing about tool selection is left to inference.

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