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

Annotations already declare readOnly/non-destructive/idempotent, so the description adds the higher-value context: it is free, it returns an UNSIGNED tx, nothing happens until the user signs and broadcasts, and the service never holds keys or funds. That is a meaningful disclosure beyond the annotations, though it omits whether the vault must already have weights set to be rebalanceable.

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?

Three short sentences, front-loaded with the value proposition ('Free') followed by the action, then the safety/return detail. Every sentence carries distinct information with no padding.

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?

An output schema exists, so the return payload needn't be fully explained, yet the description still summarizes it and covers cost, custody, and the signing requirement. For a one-parameter prepare-style tool, an agent has everything needed to call and interpret it.

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 is a single parameter with 100% schema description coverage, so the schema already documents 'vault' fully. The description adds no syntax, format, or constraint information beyond it, which is the expected baseline.

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 (rebalance) and resource (vault) plus the exact outcome: 'Brings your vault back to its target weights.' It distinguishes itself from siblings like stocks_set_weights (which changes targets) by describing a return-to-target action, and it names stocks_vault as the check source.

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?

Gives explicit context for when to call it — after checking stocks_vault: rebalanceNeeded — which is a concrete prerequisite. It does not, however, state when NOT to use it (e.g., to change target weights use stocks_set_weights), so routing guidance is clear but not fully closed.

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