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

Annotations cover read-only, idempotent, non-destructive. The description adds meaningful behavioral context beyond annotations: that this reads another user's rows only through family shares resolved by family/permissions.py (SEC-C1 validated), not raw queries, and that results include Plaid sync staleness. It does not mention pagination or limits.

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 front-loaded with the core purpose, then adds scope and return details in a structured way. It is concise but the middle sentence is slightly dense; overall it earns its place.

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 read tool, the description covers what it returns (balance, type, who shared, days_since_sync) and the security model. With annotations handling safety and no output schema, this is nearly complete; minor gaps are pagination and limits.

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?

There are 0 parameters, so the baseline is 4; the schema has no parameters to document, and the description does not need to add any.

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: lists accounts shared with you by family members, view-only. It is clearly distinguished from the sibling list_accounts (your own accounts) by the 'shared with you' scope, and from update_family_shares by being read-only.

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?

Provides clear context for when to use it (questions about a family member's finances, e.g. an elder parent's checking account). It implies the read-only share scope but does not explicitly name the alternative (list_accounts) or state exclusions.

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