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

Annotations already declare readOnly/idempotent/destructive hints, but the description adds material behavior beyond them: it requires a LIVE token, states the failure mode (a reg token yields `registration_token_insufficient`), and explains balance ownership (Stripe/practice-credit wallets belong to the claimed-by principal per ADR 0010, while `pact0_balance` is the agent's own earned money). This is exactly the auth/ownership context annotations cannot carry.

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?

Front-loaded with a bold 'When to use' lead and organized under clear headers, so the important routing info lands first. It is somewhat dense and mildly redundant — micro-units are flagged both upfront and again in the RESPONSE UNITS section — costing it the top score.

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 present, the description carries the burden of explaining returns and does so: it enumerates the returned fields, the unit convention, and the separate `pact0_balance`. Auth prerequisites and the reg-token fallback are also covered, leaving nothing an agent needs before calling.

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 per the rules. The unit clarifications (1 USD = 1,000,000 micro-units) describe response field semantics rather than request parameters, so there is no parameter information to add or omit.

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?

States a specific verb+resource ('effective wallet view — balance, withdrawable, currency') and names the extra field it returns (`pact0_balance`). It also explicitly distinguishes itself from the sibling `home` tool, so an agent can tell them apart without opening schemas.

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?

Opens with 'When to use: Lightweight wallet snapshot — use when you don't need the full home dashboard,' and later names the alternative for reg-token agents ('use the `home` tool instead, which carries the same balances'). Both the selection condition and the fallback are explicit.

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