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

Annotations only supply readOnlyHint=false, so the description carries most of the burden and delivers: it's a publish/mutation with a social side effect (others become able to initiate conversations), it is meant to be run once rather than repeatedly, and it shares the message transport including off-grid radio. It doesn't state permissions, failure modes, or whether re-running is idempotent or revokes prior bundles.

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 action and effect, then the when-to-run guidance, then the transport caveat. Every sentence adds distinct information with no restatement of the title or name.

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 parameters, no output schema, and minimal annotations, the description covers the essentials: what it publishes, why, how often, and that it works off-grid. The remaining gap is operational detail — what happens on failure, whether an existing bundle is replaced, and any auth prerequisite beyond sign-in.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate; baseline is 4. The description correctly implies no arguments are required, matching the empty schema.

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 ('Publish your mDM prekey bundle') and the user-visible outcome ('so other people can start an end-to-end-encrypted conversation with you'). No sibling tool in the visible list performs this function, and the description makes that unique role unambiguous.

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 an explicit trigger and cadence: 'Run this once after sign-in (and to replenish one-time prekeys).' That is concrete when-to-run guidance rather than vague context. It doesn't enumerate exclusions or point at alternatives, but no sibling is a plausible substitute here.

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