vaults

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

The 'Changes nothing' statement corroborates the readOnlyHint=true annotation and reinforces that this is a safe read. It goes further by disclosing the informational payload (open/locked state, read-only flag, auto-lock behavior), which helps the agent decide whether the call answers its question. It stops short of covering pagination or performance, so not a full 5.

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 tight sentences, front-loaded with the purpose, followed by the call-first guidance and the not-this routing. Every 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?

For a zero-parameter, read-only listing tool with an output schema already defined, the description supplies everything needed: what it returns, when to call it, and which sibling handles the mutating counterparts. Nothing an agent needs to call it correctly 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 tool takes zero parameters, so the baseline is 4. There is nothing for the description to clarify beyond what the empty schema already conveys.

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 vaults this app may use) and enumerates the returned attributes: open/locked, read-only, and auto-lock timing. It is immediately distinguishable from sibling tools like unlock, lock, and list_folder.

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?

Explicitly instructs 'Call it first, to learn the vault names the other tools take,' which tells the agent exactly when to invoke it. It also names the alternatives (unlock to open, lock to close) and the condition under which each applies.

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