Unlock vault

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

With no annotations, the description carries the full burden. It discloses important behavioral traits: the master password is retrieved from the OS keychain, never passed as an argument, and never reaches the model. It also states a prerequisite ordering. This adds valuable context beyond the schema, though it does not mention potential side effects or error states.

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 two sentences long, front-loaded with the core action, and every sentence earns its place. It efficiently covers purpose, security handling, and usage requirement without any unnecessary words.

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 one-parameter, no-output tool, the description is complete. It explains what the tool does, the security model for the password, and the required call order. The agent has enough context to select and invoke the tool correctly. No output schema is needed for a void operation.

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?

Schema coverage is 100% with the single parameter 'vault' described as 'Registered vault name'. The description adds little beyond that, only implying that the vault must be registered. It does not provide examples or clarify how to obtain the vault name, but the schema already handles the semantics adequately.

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 clearly states the tool's function: 'Unlocks a registered vault.' The verb 'unlocks' and the resource 'vault' are specific, and it distinguishes itself from siblings like lock_vault and list_vaults.

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 provides explicit usage guidance: 'Must be called before listing or reading entries.' This tells the agent when to use the tool. It does not explicitly mention exclusions or alternatives (e.g., when vault is already unlocked), but the requirement is clear and actionable.

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