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

Annotations already declare readOnlyHint=true, destructiveHint=false, and idempotentHint=true, covering safety. The description adds context about the return payload (metadata + nested accounts) and the id caveat, but does not disclose any side effects or additional behavioral traits. This is adequate but not rich, hence a 3.

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 compact and well-structured with Args and Returns sections. It leads with the purpose, then clarifies the parameter, then lists the return structure. Every sentence earns its place with no repetition or fluff.

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 simple read-only tool with a single parameter, the description is complete: it specifies the purpose, the exact id to use, and the shape of the response. Annotations cover safety, and sibling tools are distinguishable. Nothing essential is missing.

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 schema provides no description for item_id (0% coverage), but the description fully compensates by explaining that item_id is the PlaidItem.id, not the upstream ID. This is essential information for correct invocation and goes beyond what the schema alone could convey.

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 clear verb and resource: 'Get details for a single Plaid item, including the accounts it owns.' It distinguishes itself from list_plaid_items by specifying 'single' item, and clarifies that item_id is the internal PlaidItem.id, not upstream. This leaves no ambiguity about what the tool does.

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?

The description implies its usage context: use for a single item's detailed view; use list_plaid_items when enumerating items. It also notes the id distinction, which prevents misuse. However, it does not explicitly name sibling alternatives or state when not to use it, so it falls short of a 5.

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