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

Annotations already declare the mutation/idempotency/open-world safety profile, so the bar is lower. The description adds genuinely useful security context: it transmits only client-encrypted keys, never messages, plaintext, or private keys, to registered devices only. It still omits auth requirements or any failure/rate-limit behavior, keeping it from 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?

Two tight sentences, front-loaded with the core action and followed by the key negative guarantees. Every clause earns its place with no filler.

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 no explanation, and the privacy scope is well covered. However, for a 4-parameter required payload with 0% schema description coverage, the description leaves an agent without enough to populate the inputs confidently, which is a clear completeness gap.

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% and all four required parameters (contextId, chatId, sourceDeviceId, updates) are undocumented. The description characterizes the payload abstractly ('client-encrypted message keys') but says nothing about the meaning, format, or constraints of contextId, sourceDeviceId, messageId, or encryptionNonce, so it barely compensates.

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 (share/sync) and resource (client-encrypted message keys) scoped to the account's own registered devices. It also carves out what it is not (not a message send), which helps separate it from the many send_message/panel_send_message siblings. It stops short of naming a specific alternative, so a 4 rather than a 5.

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?

There is a scoping constraint ('only with this account's registered devices'), which implies the device-key-sync scenario, but no explicit when-to-use, prerequisites, or routing to/from the numerous sibling panel_* tools. An agent gets no guidance on when this is the right call versus e.g. panel_register_device or panel_send_message.

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