unlock_inbox

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

Annotations already declare the mutation profile (readOnlyHint=false, idempotentHint=true, destructiveHint=false), so the bar is lower. The description adds real value beyond them: the PIN never appears in tool arguments, drafts, logs, or stored state, which tells the agent the secret is handled server-side. It does not describe what unlocking changes about the inbox state or any auth prerequisite, keeping it short of a 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, zero waste. The core action is front-loaded, followed by the security invariant and the safety guardrail, in order of importance.

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?

An output schema exists, so return values need not be explained, and annotations carry the safety profile; the description covers the security and retry constraints that matter for this mutation. The only gap is that the required 'account' parameter's role is left to the schema, which has no descriptions.

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 0% for the two parameters. The description usefully clarifies that the PIN comes from an environment variable rather than a tool argument, which explains the intent of pin_env_var, but it never explains the required 'account' parameter or the default value semantics. It partially compensates for the coverage gap.

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 (unlock), a specific resource (the owner's encrypted inbox), and the mechanism (a server environment variable holding the PIN). This is clearly distinguishable from siblings like get_inbox or get_account_safety.

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 scopes to a single attempt ('once'), names the alternative for status checks (get_account_safety for remaining attempts and reset time), and states an exclusion ('never loop on a rejected PIN or challenge'). When-to-use, when-not-to-use, and the alternative are all present.

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