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

Annotations already declare read-only, idempotent, non-destructive behavior, so the redundant 'Read-only' adds little. However, the description usefully discloses the non-obvious reasons a token may be excluded (sharp price move, split/multiplier change, paused or blocked token) and the freshness signal (Chainlink price age), which is real behavioral context beyond the structured fields.

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?

A single front-loaded sentence naming the resource, followed by an enumeration of returned fields and a short read-only note. The nested parenthetical about non-lendable reasons is dense but each clause carries information; nothing is padded.

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 compensates by enumerating the returned fields (price, age, lendability, reason, LTV). Combined with annotations covering the safety profile, an agent has everything needed to call and interpret this 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?

With one parameter at 100% schema description coverage, the schema already documents the symbol filter ('One ticker, e.g. SPY. Omit for all.'). The description adds no format, matching, or error semantics for the parameter, so the baseline of 3 applies.

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 and resource ('List the Robinhood stock tokens the Priors stock vault accepts as collateral'), plus the scope of returned data (price, age, lend status, LTV). It does not differentiate itself from the sibling stock_position, which an agent could plausibly confuse with a collateral-token listing.

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?

Implied usage is clear: check which tokens are lendable right now. But there is no explicit when-to-use guidance, no statement of when to use the optional symbol filter versus omitting it, and no routing to or away from siblings like stock_position.

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