Unlock the vault

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

Annotations only declare readOnlyHint=true, so the description carries the real behavioral burden and does so well: it discloses where the auth prompt appears (Mac Touch ID prompt or local browser page), that the unlock is temporary, that the agent should never request the passphrase, and the 2-minute wait window. This is exactly the extra context annotations cannot provide.

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 core action, followed by the authentication mechanism and the waiting constraint. No filler; every sentence carries distinct information.

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?

With no output schema, the description adequately covers the action, the auth flow, the security constraint, and the timeout. It does not say what the agent should do if authentication fails or times out, a minor gap for a single-optional-parameter 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?

Schema description coverage is 100% and the single 'method' parameter already documents its enum and the meaning of 'auto'. The description alludes to Touch ID and passphrase flows but adds no syntax or selection guidance beyond the schema, so the baseline 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 ('Unlocks hidden chats') plus a temporal scope ('for a few minutes'), which cleanly separates it from siblings like lock_vault, list_hidden, and applock_status. An agent can identify the operation without opening the schema.

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 clear procedural context: the user authenticates on their own device and the agent must never ask for the passphrase in chat. It does not explicitly state when to prefer this over checking applock_status first or how it relates to lock_vault, so it stops short of full when/when-not guidance.

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