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

Disclosure is genuinely rich: 401 on bad/replayed proof, the side effect that a citizen-secret open "seals any leftover plaintext bags in place" while other proofs "change nothing," and the three auth mechanisms. However, that documented sealing side effect modifies state while the annotations declare readOnlyHint=true, so the prose conflicts with the structured safety signal.

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?

Front-loaded with the action and result, then proof mechanics and edge cases. It is dense and slightly overstuffed with auth detail, but nearly every clause (401, sealing, proofs) earns its place.

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?

Despite a high-complexity auth surface, it covers the primary action, the accepted proof forms, error behavior, side effects, and the count alternative. An output schema exists, so return values need not be re-explained; nothing material is missing for correct invocation.

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 already 100%, so the schema carries parameter meaning (baseline 3). The description adds real value by explaining how the four proof parameters compose (header Bearer vs. leave_token fallback vs. nonce + controller_public_key + controller_signature), which the schema does not spell out.

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?

Specific verb + resource: "Opens your own locker and returns your bags." It scopes the operation to "the locker of the identity you prove," which cleanly separates it from the other locker_* siblings, and names locker_desk as the non-proof alternative.

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?

It gives a clear when-to-use condition and routes count-only callers to locker_desk ("For counts without proof use locker_desk"). It does not explicitly contrast with locker_write, locker_seal, or locker_purge, but the read/open framing plus the named alternative makes selection unambiguous.

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